Commits
Bjorn Emonts authored and Ville Suoranta committed 604187d2d8a Merge
19 19 | |
20 20 | |
21 21 | |
22 22 | |
23 23 | |
24 24 | <param type="any" name="vis" kind="ms" mustexist="true"> |
25 25 | <shortdescription>Name of input visibility file(s)</shortdescription> |
26 26 | <description>Name(s) of input visibility file(s) |
27 27 | default: none; |
28 28 | example: vis='ngc5921.ms' |
29 - | vis=['ngc5921a.ms','ngc5921b.ms']; multiple MSes |
29 + | vis=['ngc5921a.ms','ngc5921b.ms']; multiple MSs |
30 30 | </description> |
31 31 | |
32 32 | <type mustexist="true">path</type><type mustexist="true">pathVec</type> |
33 33 | <value type="string"/> |
34 34 | </param> |
35 35 | |
36 36 | |
37 37 | <param type="bool" name="selectdata" visibility="hidden"> |
38 38 | <shortdescription>Enable data selection parameters</shortdescription> |
39 39 | <description>Enable data selection parameters. |
40 40 | </description> |
41 41 | <value type="bool">True</value> |
42 42 | </param> |
43 43 | |
44 44 | <param type="any" name="field" subparam="true"> |
45 45 | <shortdescription>field(s) to select</shortdescription> |
46 46 | <description> Select fields to image or mosaic. Use field id(s) or name(s). |
47 47 | ['go listobs' to obtain the list id's or names] |
48 - | default: ''= all fields |
48 + | default: ''= all fields. |
49 49 | If field string is a non-negative integer, it is assumed to |
50 - | be a field index otherwise, it is assumed to be a |
51 - | field name |
52 - | field='0~2'; field ids 0,1,2 |
53 - | field='0,4,5~7'; field ids 0,4,5,6,7 |
54 - | field='3C286,3C295'; field named 3C286 and 3C295 |
55 - | field = '3,4C\*'; field id 3, all names starting with 4C |
50 + | be a field index, otherwise it is assumed to be a |
51 + | field name. |
52 + | field='0~2'; field ids 0,1,2. |
53 + | field='0,4,5~7'; field ids 0,4,5,6,7. |
54 + | field='3C286,3C295'; field names 3C286 and 3C295. |
55 + | field = '3,4C\*'; field id 3, all names starting with 4C. |
56 56 | For multiple MS input, a list of field strings can be used: |
57 57 | field = ['0~2','0~4']; field ids 0-2 for the first MS and 0-4 |
58 - | for the second |
59 - | field = '0~2'; field ids 0-2 for all input MSes |
58 + | for the second. |
59 + | field = '0~2'; field ids 0-2 for all input MSs. |
60 60 | |
61 61 | </description> |
62 62 | <type>string</type><type>stringVec</type> |
63 63 | <value type="string"/> |
64 64 | </param> |
65 65 | |
66 66 | <param type="any" name="spw" subparam="true"> |
67 67 | <shortdescription>spw(s)/channels to select</shortdescription> |
68 - | <description> Select spectral window/channels |
69 - | NOTE: channels de-selected here will contain all zeros if |
70 - | selected by the parameter mode subparameters. |
71 - | default: ''=all spectral windows and channels |
72 - | spw='0~2,4'; spectral windows 0,1,2,4 (all channels) |
73 - | spw='0:5~61'; spw 0, channels 5 to 61 |
74 - | spw='<2'; spectral windows less than 2 (i.e. 0,1) |
75 - | spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, |
68 + | <description> Select spectral window/channels. |
69 + | NOTE: channels not selected here will contain all zeros if |
70 + | selected by other subparameters. |
71 + | default: ''=all spectral windows and channels. |
72 + | spw='0~2,4'; spectral windows 0,1,2,4 (all channels). |
73 + | spw='0:5~61'; spw 0, channels 5 to 61. |
74 + | spw='<2'; spectral windows less than 2 (i.e. 0,1). |
75 + | spw='0,10,3:3~45'; spw 0,10 all channels, and spw 3 |
76 76 | channels 3 to 45. |
77 77 | spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each. |
78 78 | For multiple MS input, a list of spw strings can be used: |
79 - | spw=['0','0~3']; spw ids 0 for the first MS and 0-3 for the second |
80 - | spw='0~3' spw ids 0-3 for all input MS |
81 - | spw='3:10~20;50~60' for multiple channel ranges within spw id 3 |
82 - | spw='3:10~20;50~60,4:0~30' for different channel ranges for spw ids 3 and 4 |
79 + | spw=['0','0~3']; spw ids 0 for the first MS and 0-3 for the second. |
80 + | spw='0~3' spw ids 0-3 for all input MS. |
81 + | spw='3:10~20;50~60' for multiple channel ranges within spw id 3. |
82 + | spw='3:10~20;50~60,4:0~30' for different channel ranges for spw ids 3 and 4. |
83 83 | spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10, |
84 - | spw 1, channels 20-30, and spw 2, channels, 1,2 and 3 |
85 - | spw='1~4;6:15~48' for channels 15 through 48 for spw ids 1,2,3,4 and 6 |
84 + | spw 1, channels 20-30, and spw 2, channels, 1,2 and 3. |
85 + | spw='1~4;6:15~48' for channels 15 through 48 for spw ids 1,2,3,4 and 6. |
86 86 | |
87 87 | </description> |
88 88 | <type>string</type><type>stringVec</type> |
89 89 | <value type="string"/> |
90 90 | </param> |
91 91 | |
92 92 | <param type="any" name="timerange" subparam="true"> |
93 93 | <shortdescription>Range of time to select from data</shortdescription> |
94 94 | <description>Range of time to select from data |
95 95 | |
96 96 | default: '' (all); examples, |
97 97 | timerange = 'YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss' |
98 98 | Note: if YYYY/MM/DD is missing date defaults to first |
99 - | day in data set |
100 - | timerange='09:14:0~09:54:0' picks 40 min on first day |
99 + | day in data set. |
100 + | timerange='09:14:0~09:54:0' picks 40 min on first day. |
101 101 | timerange='25:00:00~27:30:00' picks 1 hr to 3 hr |
102 - | 30min on NEXT day |
102 + | 30min on NEXT day. |
103 103 | timerange='09:44:00' pick data within one integration |
104 - | of time |
105 - | timerange='> 10:24:00' data after this time |
104 + | of time. |
105 + | timerange='> 10:24:00' data after this time. |
106 106 | For multiple MS input, a list of timerange strings can be |
107 107 | used: |
108 - | timerange=['09:14:0~09:54:0','> 10:24:00'] |
108 + | timerange=['09:14:0~09:54:0','> 10:24:00']. |
109 109 | timerange='09:14:0~09:54:0''; apply the same timerange for |
110 - | all input MSes |
110 + | all input MSs. |
111 111 | |
112 112 | </description> |
113 113 | <type>string</type><type>stringVec</type> |
114 114 | <value type="string"/> |
115 115 | </param> |
116 116 | |
117 117 | <param type="any" name="uvrange" subparam="true"> |
118 118 | <shortdescription>Select data within uvrange</shortdescription> |
119 119 | <description>Select data within uvrange (default unit is meters) |
120 120 | default: '' (all); example: |
121 - | uvrange='0~1000klambda'; uvrange from 0-1000 kilo-lambda |
122 - | uvrange='> 4klambda';uvranges greater than 4 kilo lambda |
121 + | uvrange='0~1000klambda'; uvrange from 0-1000 kilo-lambda. |
122 + | uvrange='> 4klambda';uvranges greater than 4 kilo lambda. |
123 123 | For multiple MS input, a list of uvrange strings can be |
124 124 | used: |
125 - | uvrange=['0~1000klambda','100~1000klamda'] |
125 + | uvrange=['0~1000klambda','100~1000klamda']. |
126 126 | uvrange='0~1000klambda'; apply 0-1000 kilo-lambda for all |
127 - | input MSes |
127 + | input MSs. |
128 + | uvrange='0~1000'; apply 0-1000 meter for all input MSs. |
128 129 | </description> |
129 130 | <type>string</type><type>stringVec</type> |
130 131 | <value type="string"/> |
131 132 | </param> |
132 133 | |
133 134 | <param type="any" name="antenna" subparam="true"> |
134 135 | <shortdescription>Select data based on antenna/baseline</shortdescription> |
135 136 | <description>Select data based on antenna/baseline |
136 137 | |
137 138 | default: '' (all) |
138 139 | If antenna string is a non-negative integer, it is |
139 140 | assumed to be an antenna index, otherwise, it is |
140 141 | considered an antenna name. |
141 142 | antenna='5\&6'; baseline between antenna index 5 and |
142 143 | index 6. |
143 144 | antenna='VA05\&VA06'; baseline between VLA antenna 5 |
144 145 | and 6. |
145 - | antenna='5\&6;7\&8'; baselines 5-6 and 7-8 |
146 - | antenna='5'; all baselines with antenna index 5 |
146 + | antenna='5\&6;7\&8'; baselines 5-6 and 7-8. |
147 + | antenna='5'; all baselines with antenna index 5. |
147 148 | antenna='05'; all baselines with antenna number 05 |
148 - | (VLA old name) |
149 + | (VLA old name). |
149 150 | antenna='5,6,9'; all baselines with antennas 5,6,9 |
150 - | index number |
151 + | index number. |
151 152 | For multiple MS input, a list of antenna strings can be |
152 153 | used: |
153 154 | antenna=['5','5\&6']; |
154 - | antenna='5'; antenna index 5 for all input MSes |
155 - | antenna='!DV14'; use all antennas except DV14 |
155 + | antenna='5'; antenna index 5 for all input MSs. |
156 + | antenna='!DV14'; use all antennas except DV14. |
156 157 | |
157 158 | </description> |
158 159 | <type>string</type><type>stringVec</type> |
159 160 | <value type="string"/> |
160 161 | </param> |
161 162 | |
162 163 | <param type="any" name="scan" subparam="true"> |
163 164 | <shortdescription>Scan number range</shortdescription> |
164 165 | <description>Scan number range |
165 166 | |
166 - | default: '' (all) |
167 - | example: scan='1~5' |
167 + | default: '' (all). |
168 + | example: scan='1~5'. |
168 169 | For multiple MS input, a list of scan strings can be used: |
169 - | scan=['0~100','10~200'] |
170 - | scan='0~100; scan ids 0-100 for all input MSes |
170 + | scan=['0~100','10~200']. |
171 + | scan='0~100; scan ids 0-100 for all input MSs. |
171 172 | |
172 173 | </description> |
173 174 | <type>string</type><type>stringVec</type> |
174 175 | <value type="string"/> |
175 176 | </param> |
176 177 | |
177 178 | <param type="any" name="observation" subparam="true"> |
178 179 | <shortdescription>Observation ID range</shortdescription> |
179 180 | <description>Observation ID range |
180 - | default: '' (all) |
181 - | example: observation='1~5' |
181 + | default: '' (all). |
182 + | example: observation='1~5'. |
182 183 | </description> |
183 184 | <type>string</type><type>int</type> |
184 185 | <value type="string"/> |
185 186 | </param> |
186 187 | |
187 188 | <param type="any" name="intent" subparam="true"> |
188 189 | <shortdescription>Scan Intent(s)</shortdescription> |
189 190 | <description>Scan Intent(s) |
190 191 | |
191 - | default: '' (all) |
192 - | example: intent='TARGET_SOURCE' |
193 - | example: intent='TARGET_SOURCE1,TARGET_SOURCE2' |
194 - | example: intent='TARGET_POINTING\*' |
192 + | default: '' (all). |
193 + | example: intent='TARGET_SOURCE'. |
194 + | example: intent='TARGET_SOURCE1,TARGET_SOURCE2'. |
195 + | example: intent='TARGET_POINTING\*'. |
195 196 | </description> |
196 197 | <type>string</type><type>stringVec</type> |
197 198 | <value type="string"/> |
198 199 | </param> |
199 200 | |
200 201 | <param type="string" name="datacolumn"> |
201 202 | <shortdescription>Data column to image(data,corrected)</shortdescription> |
202 203 | <description>Data column to image (data or observed, corrected) |
203 204 | default:'corrected' |
204 205 | ( If 'corrected' does not exist, it will use 'data' instead ) |
213 214 | |
214 215 | |
215 216 | <param type="any" name="imagename" required="true"> |
216 217 | <shortdescription>Pre-name of output images</shortdescription> |
217 218 | <description>Pre-name of output images |
218 219 | |
219 220 | example : imagename='try' |
220 221 | |
221 222 | Output images will be (a subset of) : |
222 223 | |
223 - | try.psf - Point spread function |
224 - | try.residual - Residual image |
225 - | try.image - Restored image |
226 - | try.model - Model image (contains only flux components) |
227 - | try.sumwt - Single pixel image containing sum-of-weights. |
228 - | (for natural weighting, sensitivity=1/sqrt(sumwt)) |
229 - | try.pb - Primary beam model (values depend on the gridder used) |
224 + | try.psf - Point Spread Function (PSF). |
225 + | try.residual - Residual image. |
226 + | try.image - Restored image. |
227 + | try.model - Model image (contains only flux components). |
228 + | try.sumwt - Single pixel image containing sum-of-weights. |
229 + | (for natural weighting, sensitivity=1/sqrt(sumwt)). |
230 + | try.pb - Primary Beam (PB) model (values depend on the gridder used). |
230 231 | |
231 232 | Widefield projection algorithms (gridder=mosaic,awproject) will |
232 233 | compute the following images too. |
233 234 | try.weight - FT of gridded weights or the |
234 - | un-normalized sum of PB-square (for all pointings) |
235 - | Here, PB = sqrt(weight) normalized to a maximum of 1.0 |
235 + | un-normalized sum of PB-square (for all pointings). |
236 + | Here, PB = sqrt(weight) normalized to a maximum of 1.0. |
236 237 | |
237 238 | For multi-term wideband imaging, all relevant images above will |
238 239 | have additional .tt0,.tt1, etc suffixes to indicate Taylor terms, |
239 240 | plus the following extra output images. |
240 - | try.alpha - spectral index |
241 - | try.alpha.error - estimate of error on spectral index |
242 - | try.beta - spectral curvature (if nterms \> 2) |
241 + | try.alpha - spectral index. |
242 + | try.alpha.error - estimate of error on spectral index. |
243 + | try.beta - spectral curvature (if nterms \> 2). |
243 244 | |
244 245 | Tip : Include a directory name in 'imagename' for all |
245 246 | output images to be sent there instead of the |
246 - | current working directory : imagename='mydir/try' |
247 + | current working directory : imagename='mydir/try'. |
247 248 | |
248 249 | Tip : Restarting an imaging run without changing 'imagename' |
249 250 | implies continuation from the existing model image on disk. |
250 251 | - If 'startmodel' was initially specified it needs to be set to "" |
251 252 | for the restart run (or tclean will exit with an error message). |
252 253 | - By default, the residual image and psf will be recomputed |
253 254 | but if no changes were made to relevant parameters between |
254 255 | the runs, set calcres=False, calcpsf=False to resume directly from |
255 256 | the minor cycle without the (unnecessary) first major cycle. |
256 257 | To automatically change 'imagename' with a numerical |
263 264 | </description> |
264 265 | <type>int</type><type>string</type><type>stringVec</type> |
265 266 | <value type="string"/> |
266 267 | </param> |
267 268 | |
268 269 | <param type="any" name="imsize"> |
269 270 | <shortdescription>Number of pixels</shortdescription> |
270 271 | <description>Number of pixels |
271 272 | example: |
272 273 | |
273 - | imsize = [350,250] |
274 - | imsize = 500 is equivalent to [500,500] |
274 + | imsize = [350,250]. |
275 + | imsize = 500 is equivalent to [500,500]. |
275 276 | |
276 277 | To take proper advantage of internal optimized FFT routines, the |
277 278 | number of pixels must be even and factorizable by 2,3,5 only. |
278 279 | To find the nearest optimal imsize to that desired by the user, please use the following tool method: |
279 280 | |
280 281 | from casatools import synthesisutils |
281 282 | su = synthesisutils() |
282 283 | su.getOptimumSize(345) |
283 284 | Output : 360 |
284 285 | </description> |
285 286 | <type>int</type><type>intVec</type> |
286 287 | <value type="intVec"><value>100</value></value> |
287 288 | </param> |
288 289 | |
289 290 | <param type="any" name="cell"> |
290 291 | <shortdescription>Cell size</shortdescription> |
291 292 | <description>Cell size |
292 293 | example: cell=['0.5arcsec,'0.5arcsec'] or |
293 - | cell=['1arcmin', '1arcmin'] |
294 - | cell = '1arcsec' is equivalent to ['1arcsec','1arcsec'] |
294 + | cell=['1arcmin', '1arcmin']. |
295 + | cell = '1arcsec' is equivalent to ['1arcsec','1arcsec']. |
295 296 | </description> |
296 297 | <type>int</type><type>double</type><type>intVec</type><type>doubleVec</type><type>string</type><type>stringVec</type> |
297 298 | <value type="stringVec">"1arcsec"</value> |
298 299 | </param> |
299 300 | |
300 301 | <param type="any" name="phasecenter"> |
301 302 | <shortdescription>Phase center of the image</shortdescription> |
302 303 | <description>Phase center of the image (string or field id); if the phasecenter is the name known major solar system object ('MERCURY', 'VENUS', 'MARS', 'JUPITER', 'SATURN', 'URANUS', 'NEPTUNE', 'PLUTO', 'SUN', 'MOON') or is an ephemerides table then that source is tracked and the background sources get smeared. There is a special case, when phasecenter='TRACKFIELD', which will use the ephemerides or polynomial phasecenter in the FIELD table of the MS's as the source center to track. |
303 304 | |
304 305 | Note : If unspecified, tclean will use the phase-center from the first data field of the MS (or list of MSs) selected for imaging. |
305 306 | |
306 - | example: phasecenter=6 |
307 - | phasecenter='J2000 19h30m00 -40d00m00' |
308 - | phasecenter='J2000 292.5deg -40.0deg' |
309 - | phasecenter='J2000 5.105rad -0.698rad' |
310 - | phasecenter='ICRS 13:05:27.2780 -049.28.04.458' |
311 - | phasecenter='myComet_ephem.tab' |
312 - | phasecenter='MOON' |
313 - | phasecenter='TRACKFIELD' |
307 + | example: phasecenter='6'. |
308 + | phasecenter='J2000 19h30m00 -40d00m00'. |
309 + | phasecenter='J2000 292.5deg -40.0deg'. |
310 + | phasecenter='J2000 5.105rad -0.698rad'. |
311 + | phasecenter='ICRS 13:05:27.2780 -049.28.04.458'. |
312 + | phasecenter='myComet_ephem.tab'. |
313 + | phasecenter='MOON'. |
314 + | phasecenter='TRACKFIELD'. |
314 315 | </description> |
315 316 | <type>int</type><type>string</type> |
316 317 | <value type="string"/> |
317 318 | </param> |
318 319 | |
319 320 | |
320 321 | <param type="string" name="stokes"> |
321 322 | <shortdescription>Stokes Planes to make</shortdescription> |
322 323 | <description>Stokes Planes to make |
323 324 | default='I'; example: stokes='IQUV'; |
324 325 | Options: 'I','Q','U','V','IV','QU','IQ','UV','IQUV','RR','LL','XX','YY','RRLL','XXYY','pseudoI' |
325 326 | |
326 327 | Note : Due to current internal code constraints, if any correlation pair |
327 328 | is flagged, by default, no data for that row in the MS will be used. |
328 329 | So, in an MS with XX,YY, if only YY is flagged, neither a |
329 330 | Stokes I image nor an XX image can be made from those data points. |
330 331 | In such a situation, please split out only the unflagged correlation into |
331 - | a separate MS. |
332 + | a separate MS, or use the option 'pseudoI'. |
332 333 | |
333 334 | Note : The 'pseudoI' option is a partial solution, allowing Stokes I imaging |
334 335 | when either of the parallel-hand correlations are unflagged. |
335 336 | |
336 337 | The remaining constraints shall be removed (where logical) in a future release. |
337 338 | |
338 339 | </description> |
339 340 | <value type="string">I</value> |
340 341 | <allowed kind="enum"> |
341 342 | <value>I</value> |
353 354 | <value>YY</value> |
354 355 | <value>RRLL</value> |
355 356 | <value>XXYY</value> |
356 357 | <value>pseudoI</value> |
357 358 | </allowed> |
358 359 | </param> |
359 360 | |
360 361 | <param type="string" name="projection"> |
361 362 | <shortdescription>Coordinate projection </shortdescription> |
362 363 | <description>Coordinate projection |
363 - | Examples : SIN, NCP |
364 + | Examples : SIN, NCP. |
364 365 | A list of supported (but untested) projections can be found here : |
365 366 | http://casa.nrao.edu/active/docs/doxygen/html/classcasa_1_1Projection.html#a3d5f9ec787e4eabdce57ab5edaf7c0cd |
366 367 | |
367 368 | |
368 369 | |
369 370 | </description> |
370 371 | <value type="string">SIN</value> |
371 372 | </param> |
372 373 | |
373 374 | <param type="any" name="startmodel"> |
374 375 | <shortdescription>Name of starting model image</shortdescription> |
375 376 | <description>Name of starting model image |
376 377 | |
377 378 | The contents of the supplied starting model image will be |
378 379 | copied to the imagename.model before the run begins. |
379 380 | |
380 - | example : startmodel = 'singledish.im' |
381 + | example : startmodel = 'singledish.im'. |
381 382 | |
382 383 | For deconvolver='mtmfs', one image per Taylor term must be provided. |
383 - | example : startmodel = ['try.model.tt0', 'try.model.tt1'] |
384 + | example : startmodel = ['try.model.tt0', 'try.model.tt1']. |
384 385 | startmodel = ['try.model.tt0'] will use a starting model only |
385 386 | for the zeroth order term. |
386 387 | startmodel = ['','try.model.tt1'] will use a starting model only |
387 388 | for the first order term. |
388 389 | |
389 390 | This starting model can be of a different image shape and size from |
390 391 | what is currently being imaged. If so, an image regrid is first triggered |
391 392 | to resample the input image onto the target coordinate system. |
392 393 | |
393 - | A common usage is to set this parameter equal to a single dish image |
394 + | A common usage is to set this parameter equal to a single dish image. |
394 395 | |
395 396 | Negative components in the model image will be included as is. |
396 397 | |
397 - | [ Note : If an error occurs during image resampling/regridding, |
398 + | Note : If an error occurs during image resampling/regridding, |
398 399 | please try using task imregrid to resample the starting model |
399 400 | image onto a CASA image with the target shape and |
400 - | coordinate system before supplying it via startmodel ] |
401 + | coordinate system before supplying it via startmodel. |
401 402 | |
402 403 | </description> |
403 404 | <value type="string"/> |
404 405 | </param> |
405 406 | |
406 407 | |
407 408 | |
408 409 | |
409 410 | |
410 411 | |
411 412 | |
412 413 | <param type="string" name="specmode" required="true"> |
413 414 | <shortdescription>Spectral definition mode (mfs,cube,cubedata, cubesource,mvc)</shortdescription> |
414 415 | <description>Spectral definition mode (mfs,cube,cubedata, cubesource, mvc) |
415 416 | |
416 417 | specmode='mfs' : Continuum imaging with only one output image channel. |
417 418 | (mode='cont' can also be used here) |
418 419 | |
419 - | specmode='cube' : Spectral line imaging with one or more channels |
420 + | specmode='cube' : Spectral line imaging with one or more channels. |
420 421 | Parameters start, width,and nchan define the spectral |
421 422 | coordinate system and can be specified either in terms |
422 423 | of channel numbers, frequency or velocity in whatever |
423 424 | spectral frame is specified in 'outframe'. |
424 425 | All internal and output images are made with outframe as the |
425 426 | base spectral frame. However imaging code internally uses the fixed |
426 427 | spectral frame, LSRK for automatic internal software |
427 - | Doppler tracking so that a spectral line observed over an |
428 + | Doppler correction, so that a spectral line observed over an |
428 429 | extended time range will line up appropriately. |
429 430 | Therefore the output images have additional spectral frame conversion |
430 431 | layer in LSRK on the top the base frame. |
431 432 | |
432 - | |
433 - | (Note : Even if the input parameters are specified in a frame |
434 - | other than LSRK, the viewer still displays spectral |
435 - | axis in LSRK by default because of the conversion frame |
436 - | layer mentioned above. The viewer can be used to relabel |
437 - | the spectral axis in any desired frame - via the spectral |
438 - | reference option under axis label properties in the |
439 - | data display options window.) |
440 - | |
441 - | |
442 433 | |
443 434 | |
444 435 | |
445 - | specmode='cubedata' : Spectral line imaging with one or more channels |
446 - | There is no internal software Doppler tracking so |
436 + | specmode='cubedata' : Spectral line imaging with one or more channels. |
437 + | There is no internal software Doppler correction, so |
447 438 | a spectral line observed over an extended time range |
448 439 | may be smeared out in frequency. There is strictly |
449 440 | no valid spectral frame with which to associate with the |
450 441 | output images, thus the image spectral frame will |
451 442 | be labelled "Undefined". |
452 443 | |
453 444 | |
454 445 | specmode='cubesource': Spectral line imaging while |
455 446 | tracking moving source (near field or solar system |
456 447 | objects). The velocity of the source is accounted |
457 448 | and the frequency reported is in the source frame. |
458 449 | As there is no "SOURCE" frame defined in CASA, |
459 450 | the frame in the image will be labelled "REST" (but do note the |
460 451 | velocity of a given line reported may be different from the rest frame |
461 452 | velocity if the emission region is moving w.r.t the systemic |
462 - | velocity frame of the source) |
453 + | velocity frame of the source). |
463 454 | |
464 455 | specmode='mvc' : Multiterm continuum imaging with cube major cycles. |
465 456 | This mode requires deconvolver='mtmfs' with nterms>1 |
466 457 | and user-set choices of 'reffreq' and 'nchan'. |
467 458 | |
468 459 | The output images and minor cycle are similar to specmode='mfs' |
469 460 | with deconvolver='mtmfs', but the major cycles are done in |
470 461 | cube mode (and require a setting of 'reffreq' and 'nchan'). |
471 462 | By default, frequency-dependent primary beam correction is |
472 463 | applied to each channel, before being combined across frequency |
512 503 | <value>cont</value> |
513 504 | <value>cube</value> |
514 505 | <value>cubedata</value> |
515 506 | <value>cubesource</value> |
516 507 | <value>mvc</value> |
517 508 | </allowed> |
518 509 | </param> |
519 510 | |
520 511 | <param type="any" name="reffreq" subparam="true"> |
521 512 | <shortdescription>Reference frequency</shortdescription> |
522 - | <description>Reference frequency of the output image coordinate system |
513 + | <description>Reference frequency of the output image coordinate system. |
523 514 | |
524 515 | Example : reffreq='1.5GHz' as a string with units. |
525 516 | |
526 517 | By default, it is calculated as the middle of the selected frequency range. |
527 518 | |
528 519 | For deconvolver='mtmfs' the Taylor expansion is also done about |
529 520 | this specified reference frequency. |
530 521 | |
531 522 | </description> |
532 523 | <value type="string"/> |
533 524 | </param> |
534 525 | |
535 526 | <param type="int" name="nchan" subparam="true"> |
536 527 | <shortdescription>Number of channels in the output image</shortdescription> |
537 - | <description>Number of channels in the output image |
528 + | <description>Number of channels in the output image. |
538 529 | For default (=-1), the number of channels will be automatically determined |
539 530 | based on data selected by 'spw' with 'start' and 'width'. |
540 531 | It is often easiest to leave nchan at the default value. |
541 532 | example: nchan=100 |
542 533 | |
543 534 | </description> |
544 535 | <value type="int">-1</value> |
545 536 | </param> |
546 537 | |
547 538 | <param type="any" name="start" subparam="true"> |
555 546 | Since the integer number in 'start' represents the data channel number, |
556 547 | when the channel number is used along with the spectral window id selection |
557 548 | in 'spw', 'start' specified as an integer should be carefully set otherwise |
558 549 | it may result in the blank image channels if the 'start' channel (i.e. absolute |
559 550 | channel number) is outside of the channel range specified in 'spw'. |
560 551 | In such a case, 'start' can be left as a default (='') to ensure |
561 552 | matching with the data spectral channel selection. |
562 553 | For specmode='cube', when velocity or frequency is used it is |
563 554 | interpreted with the frame defined in outframe. [The parameters of |
564 555 | the desired output cube can be estimated by using the 'transform' |
565 - | functionality of 'plotms'] |
566 - | examples: start='5.0km/s'; 1st channel, 5.0km/s in outframe |
567 - | start='22.3GHz'; 1st channel, 22.3GHz in outframe |
556 + | functionality of 'plotms']. |
557 + | examples: start='5.0km/s'; 1st channel, 5.0km/s in outframe. |
558 + | start='22.3GHz'; 1st channel, 22.3GHz in outframe. |
568 559 | </description> |
569 560 | <value type="string"/> |
570 561 | </param> |
571 562 | |
572 563 | <param type="any" name="width" subparam="true"> |
573 564 | <shortdescription>Channel width (e.g. width=2,width=\'0.1MHz\',width=\'10km/s\')</shortdescription> |
574 565 | <description>Channel width (e.g. width=2,width=\'0.1MHz\',width=\'10km/s\') of output cube images |
575 566 | specified by data channel number (integer), velocity (string with a unit), or |
576 567 | or frequency (string with a unit). |
577 - | Default:''; data channel width |
568 + | Default:''; data channel width. |
578 569 | The sign of width defines the direction of the channels to be incremented. |
579 570 | For width specified in velocity or frequency with '-' in front gives image channels in |
580 571 | decreasing velocity or frequency, respectively. |
581 572 | For specmode='cube', when velocity or frequency is used it is interpreted with |
582 573 | the reference frame defined in outframe. |
583 - | examples: width='2.0km/s'; results in channels with increasing velocity |
584 - | width='-2.0km/s'; results in channels with decreasing velocity |
585 - | width='40kHz'; results in channels with increasing frequency |
574 + | examples: width='2.0km/s'; results in channels with increasing velocity. |
575 + | width='-2.0km/s'; results in channels with decreasing velocity. |
576 + | width='40kHz'; results in channels with increasing frequency. |
586 577 | width=-2; results in channels averaged of 2 data channels incremented from |
587 - | high to low channel numbers |
578 + | high to low channel numbers. |
588 579 | |
589 580 | </description> |
590 581 | <value type="string"/> |
591 582 | </param> |
592 583 | |
593 584 | <param type="string" name="outframe" subparam="true"> |
594 585 | <shortdescription>Spectral reference frame in which to interpret \'start\' and \'width\'</shortdescription> |
595 586 | <description>Spectral reference frame in which to interpret \'start\' and \'width\' |
596 587 | Options: '','LSRK','LSRD','BARY','GEO','TOPO','GALACTO','LGROUP','CMB' |
597 - | example: outframe='bary' for Barycentric frame |
598 - | |
599 - | REST -- Rest frequency |
600 - | LSRD -- Local Standard of Rest (J2000) |
601 - | -- as the dynamical definition (IAU, [9,12,7] km/s in galactic coordinates) |
602 - | LSRK -- LSR as a kinematical (radio) definition |
603 - | -- 20.0 km/s in direction ra,dec = [270,+30] deg (B1900.0) |
604 - | BARY -- Barycentric (J2000) |
605 - | GEO --- Geocentric |
606 - | TOPO -- Topocentric |
588 + | example: outframe='bary' for Barycentric frame. |
589 + | |
590 + | REST -- Rest frequency. |
591 + | LSRD -- Local Standard of Rest (J2000). |
592 + | -- as the dynamical definition (IAU, [9,12,7] km/s in galactic coordinates). |
593 + | LSRK -- LSR as a kinematical (radio) definition. |
594 + | -- 20.0 km/s in direction ra,dec = [270,+30] deg (B1900.0). |
595 + | BARY -- Barycentric (J2000). |
596 + | GEO --- Geocentric. |
597 + | TOPO -- Topocentric. |
607 598 | GALACTO -- Galacto centric (with rotation of 220 km/s in direction l,b = [90,0] deg. |
608 - | LGROUP -- Local group velocity -- 308km/s towards l,b = [105,-7] deg (F. Ghigo) |
609 - | CMB -- CMB velocity -- 369.5km/s towards l,b = [264.4, 48.4] deg (F. Ghigo) |
610 - | DEFAULT = LSRK |
599 + | LGROUP -- Local group velocity -- 308km/s towards l,b = [105,-7] deg (F. Ghigo). |
600 + | CMB -- CMB velocity -- 369.5km/s towards l,b = [264.4, 48.4] deg (F. Ghigo). |
601 + | DEFAULT = LSRK. |
611 602 | |
612 603 | </description> |
613 604 | <value type="string">LSRK</value> |
614 605 | </param> |
615 606 | |
616 607 | <param type="string" name="veltype" subparam="true"> |
617 608 | <shortdescription>Velocity type (radio, z, ratio, beta, gamma, optical)</shortdescription> |
618 609 | <description>Velocity type (radio, z, ratio, beta, gamma, optical) |
619 - | For start and/or width specified in velocity, specifies the velocity definition |
610 + | For 'start' and/or 'width' specified in velocity, specifies the velocity definition |
620 611 | Options: 'radio','optical','z','beta','gamma','optical' |
621 612 | NOTE: the viewer always defaults to displaying the 'radio' frame, |
622 613 | but that can be changed in the position tracking pull down. |
623 614 | |
624 615 | The different types (with F = f/f0, the frequency ratio), are: |
625 616 | |
626 - | Z = (-1 + 1/F) |
627 - | RATIO = (F) \* |
628 - | RADIO = (1 - F) |
629 - | OPTICAL == Z |
630 - | BETA = ((1 - F2)/(1 + F2)) |
631 - | GAMMA = ((1 + F2)/2F) \* |
632 - | RELATIVISTIC == BETA (== v/c) |
633 - | DEFAULT == RADIO |
617 + | Z = (-1 + 1/F). |
618 + | RATIO = (F) \*. |
619 + | RADIO = (1 - F). |
620 + | OPTICAL == Z. |
621 + | BETA = ((1 - F^2)/(1 + F^2)). |
622 + | GAMMA = ((1 + F^2)/2F) \*. |
623 + | RELATIVISTIC == BETA (== v/c). |
624 + | DEFAULT == RADIO. |
634 625 | Note that the ones with an '\*' have no real interpretation |
635 626 | (although the calculation will proceed) if given as a velocity. |
636 627 | |
637 628 | </description> |
638 629 | <value type="string">radio</value> |
639 630 | </param> |
640 631 | |
641 632 | <param type="any" name="restfreq" subparam="true"> |
642 633 | <shortdescription>List of rest frequencies</shortdescription> |
643 634 | <description>List of rest frequencies or a rest frequency in a string. |
644 635 | Specify rest frequency to use for output image. |
645 - | \*Currently it uses the first rest frequency in the list for translation of |
636 + | |
637 + | Currently it uses the first rest frequency in the list for translation of |
646 638 | velocities. The list will be stored in the output images. |
647 639 | Default: []; look for the rest frequency stored in the MS, if not available, |
648 - | use center frequency of the selected channels |
649 - | examples: restfreq=['1.42GHz'] |
650 - | restfreq='1.42GHz' |
640 + | use center frequency of the selected channels. |
641 + | examples: restfreq=['1.42GHz']. |
642 + | restfreq='1.42GHz'. |
651 643 | |
652 644 | </description> |
653 645 | <value type="stringVec"/> |
654 646 | </param> |
655 647 | |
656 648 | |
657 649 | |
658 650 | <param type="string" name="interpolation" subparam="true"> |
659 651 | <shortdescription>Spectral interpolation (nearest,linear,cubic)</shortdescription> |
660 652 | <description>Spectral interpolation (nearest,linear,cubic) |
742 734 | <description>Gridding options (standard, wproject, widefield, mosaic, awproject) |
743 735 | |
744 736 | The following options choose different gridding convolution |
745 737 | functions for the process of convolutional resampling of the measured |
746 738 | visibilities onto a regular uv-grid prior to an inverse FFT. |
747 739 | Model prediction (degridding) also uses these same functions. |
748 740 | Several wide-field effects can be accounted for via careful choices of |
749 741 | convolution functions. Gridding (degridding) runtime will rise in |
750 742 | proportion to the support size of these convolution functions (in uv-pixels). |
751 743 | |
752 - | standard : Prolate Spheroid with 7x7 uv pixel support size |
744 + | standard : Prolate Spheroid with 7x7 uv pixel support size. |
753 745 | |
754 746 | [ This mode can also be invoked using 'ft' or 'gridft' ] |
755 747 | |
756 748 | wproject : W-Projection algorithm to correct for the widefield |
757 749 | non-coplanar baseline effect. [Cornwell et.al 2008] |
758 750 | |
759 751 | wprojplanes is the number of distinct w-values at |
760 752 | which to compute and use different gridding convolution |
761 753 | functions (see help for wprojplanes). |
762 754 | Convolution function support size can range |
766 758 | |
767 759 | widefield : Facetted imaging with or without W-Projection per facet. |
768 760 | |
769 761 | A set of facets x facets subregions of the specified image |
770 762 | are gridded separately using their respective phase centers |
771 763 | (to minimize max W). Deconvolution is done on the joint |
772 764 | full size image, using a PSF from the first subregion. |
773 765 | |
774 766 | wprojplanes=1 : standard prolate spheroid gridder per facet. |
775 767 | wprojplanes > 1 : W-Projection gridder per facet. |
776 - | nfacets=1, wprojplanes > 1 : Pure W-Projection and no facetting |
777 - | nfacets=1, wprojplanes=1 : Same as standard,ft,gridft |
768 + | nfacets=1, wprojplanes > 1 : Pure W-Projection and no facetting. |
769 + | nfacets=1, wprojplanes=1 : Same as standard,ft,gridft. |
778 770 | |
779 771 | A combination of facetting and W-Projection is relevant only for |
780 772 | very large fields of view. (In our current version of tclean, this |
781 773 | combination runs only with parallel=False. |
782 774 | |
783 775 | mosaic : A-Projection with azimuthally symmetric beams without |
784 776 | sidelobes, beam rotation or squint correction. |
785 777 | Gridding convolution functions per visibility are computed |
786 778 | from FTs of PB models per antenna. |
787 779 | This gridder can be run on single fields as well as mosaics. |
788 780 | |
789 - | VLA : PB polynomial fit model (Napier and Rots, 1982) |
790 - | EVLA : PB polynomial fit model (Perley, 2015) |
781 + | VLA : PB polynomial fit model (Napier and Rots, 1982). |
782 + | EVLA : PB polynomial fit model (Perley, 2015). |
791 783 | ALMA : Airy disks for a 10.7m dish (for 12m dishes) and |
792 784 | 6.25m dish (for 7m dishes) each with 0.75m |
793 785 | blockages (Hunter/Brogan 2011). Joint mosaic |
794 786 | imaging supports heterogeneous arrays for ALMA. |
795 787 | |
796 788 | Typical gridding convolution function support sizes are |
797 789 | between 7 and 50 depending on the desired |
798 790 | accuracy (given by the uv cell size or image field of view). |
799 791 | |
800 792 | [ This mode can also be invoked using 'mosaicft' or 'ftmosaic' ] |
805 797 | [Bhatnagar et.al, 2008] |
806 798 | |
807 799 | Gridding convolution functions are computed from |
808 800 | aperture illumination models per antenna and optionally |
809 801 | combined with W-Projection kernels and a prolate spheroid. |
810 802 | This gridder can be run on single fields as well as mosaics. |
811 803 | |
812 804 | VLA : Uses ray traced model (VLA and EVLA) including feed |
813 805 | leg and subreflector shadows, off-axis feed location |
814 806 | (for beam squint and other polarization effects), and |
815 - | a Gaussian fit for the feed beams (Ref: Brisken 2009) |
807 + | a Gaussian fit for the feed beams (Brisken 2009) |
816 808 | ALMA : Similar ray-traced model as above (but the correctness |
817 809 | of its polarization properties remains un-verified). |
818 810 | |
819 811 | Typical gridding convolution function support sizes are |
820 812 | between 7 and 50 depending on the desired |
821 813 | accuracy (given by the uv cell size or image field of view). |
822 814 | When combined with W-Projection they can be significantly larger. |
823 815 | |
824 816 | [ This mode can also be invoked using 'awprojectft' ] |
825 817 | |
826 - | imagemosaic : (untested implementation) |
818 + | imagemosaic : (untested implementation). |
827 819 | Grid and iFT each pointing separately and combine the |
828 820 | images as a linear mosaic (weighted by a PB model) in |
829 821 | the image domain before a joint minor cycle. |
830 822 | |
831 - | VLA/ALMA PB models are same as for gridder='mosaicft' |
823 + | VLA/ALMA PB models are same as for gridder='mosaicft'. |
832 824 | |
833 825 | ------ Notes on PB models : |
834 826 | |
835 827 | (1) Several different sources of PB models are used in the modes |
836 828 | listed above. This is partly for reasons of algorithmic flexibility |
837 829 | and partly due to the current lack of a common beam model |
838 830 | repository or consensus on what beam models are most appropriate. |
839 831 | |
840 832 | (2) For ALMA and gridder='mosaic', ray-traced (TICRA) beams |
841 833 | are also available via the vpmanager tool. |
857 849 | (which needs a 1/0 mask). There are two options for making a pb based |
858 850 | deconvolution mask. |
859 851 | -- Run tclean with niter=0 to produce the .pb, construct a 1/0 image |
860 852 | with the desired threshold (using ia.open('newmask.im'); |
861 853 | ia.calc('iif("xxx.pb">0.3,1.0,0.0)');ia.close() for example), |
862 854 | and supply it via the 'mask' parameter in a subsequent run |
863 855 | (with calcres=F and calcpsf=F to restart directly from the minor cycle). |
864 856 | -- Run tclean with usemask='pb' for it to automatically construct |
865 857 | a 1/0 mask from the internal T/F mask from .pb at a fixed 0.2 threshold. |
866 858 | |
867 - | ----- Making PBs for gridders other than mosaic,awproject |
859 + | ----- Making PBs for gridders other than mosaic,awproject. |
868 860 | |
869 861 | After the PSF generation, a PB is constructed using the same |
870 862 | models used in gridder='mosaic' but just evaluated in the image |
871 863 | domain without consideration to weights. |
872 864 | |
873 865 | </description> |
874 866 | <value type="string">standard</value> |
875 867 | <allowed kind="enum"> |
876 868 | <value>standard</value> |
877 869 | <value>ft</value> |
911 903 | optional direction. You may need to use |
912 904 | this if for example the mosaic does not |
913 905 | have any pointing in the center of the |
914 906 | image. Another reason; as the psf is |
915 907 | approximate for a mosaic, this may help |
916 908 | to deconvolve a non central bright source |
917 909 | well and quickly. |
918 910 | |
919 911 | example: |
920 912 | |
921 - | psfphasecenter=6 #center psf on field 6 |
922 - | psfphasecenter='J2000 19h30m00 -40d00m00' |
923 - | psfphasecenter='J2000 292.5deg -40.0deg' |
924 - | psfphasecenter='J2000 5.105rad -0.698rad' |
925 - | psfphasecenter='ICRS 13:05:27.2780 -049.28.04.458' |
913 + | psfphasecenter='6' #center psf on field 6. |
914 + | psfphasecenter='J2000 19h30m00 -40d00m00'. |
915 + | psfphasecenter='J2000 292.5deg -40.0deg'. |
916 + | psfphasecenter='J2000 5.105rad -0.698rad'. |
917 + | psfphasecenter='ICRS 13:05:27.2780 -049.28.04.458'. |
926 918 | </description> |
927 919 | <type>int</type><type>string</type> |
928 920 | <value type="string"/> |
929 921 | </param> |
930 922 | |
931 923 | <param type="int" name="wprojplanes" subparam="true"> |
932 924 | <shortdescription>Number of distinct w-values for convolution functions</shortdescription> |
933 925 | <description>Number of distinct w-values at which to compute and use different |
934 926 | gridding convolution functions for W-Projection |
935 927 | |
956 948 | in which the number of planes is automatically computed. |
957 949 | |
958 950 | </description> |
959 951 | <value type="int">1</value> |
960 952 | </param> |
961 953 | |
962 954 | <param type="string" name="vptable" subparam="true"> |
963 955 | <shortdescription>Name of Voltage Pattern table</shortdescription> |
964 956 | <description> VP table saved via the vpmanager |
965 957 | |
966 - | vptable="" : Choose default beams for different telescopes |
967 - | ALMA : Airy disks |
958 + | vptable="" : Choose default beams for different telescopes. |
959 + | ALMA : Airy disks. |
968 960 | EVLA : old VLA models. |
969 961 | |
970 962 | Other primary beam models can be chosen via the vpmanager tool. |
971 963 | |
972 - | Step 1 : Set up the vpmanager tool and save its state in a table |
964 + | Step 1 : Set up the vpmanager tool and save its state in a table. |
973 965 | |
974 966 | vp.setpbpoly(telescope='EVLA', coeff=[1.0, -1.529e-3, 8.69e-7, -1.88e-10]) |
975 967 | vp.saveastable('myvp.tab') |
976 968 | |
977 969 | Step 2 : Supply the name of that table in tclean. |
978 970 | |
979 971 | tclean(....., vptable='myvp.tab',....) |
980 972 | |
981 973 | Please see the documentation for the vpmanager for more details on how to |
982 974 | choose different beam models. Work is in progress to update the defaults |
991 983 | <value type="string"/> |
992 984 | </param> |
993 985 | <param type="bool" name="mosweight" subparam="true"> |
994 986 | <shortdescription>Indepently weight each field in a mosaic</shortdescription> |
995 987 | <description>When doing Brigg's style weighting (including uniform) to perform the weight density calculation for each field indepedently if True. If False the weight density is calculated from the average uv distribution of all the fields. |
996 988 | </description> |
997 989 | <value type="bool">True</value> |
998 990 | </param> |
999 991 | <param type="bool" name="aterm" subparam="true"> |
1000 992 | <shortdescription>Use aperture illumination functions during gridding</shortdescription> |
1001 - | <description>Use aperture illumination functions during gridding |
993 + | <description>Use aperture illumination functions during gridding. |
1002 994 | |
1003 995 | This parameter turns on the A-term of the AW-Projection gridder. |
1004 996 | Gridding convolution functions are constructed from aperture illumination |
1005 997 | function models of each antenna. |
1006 998 | |
1007 999 | </description> |
1008 1000 | <value type="bool">True</value> |
1009 1001 | </param> |
1010 1002 | |
1011 1003 | <param type="bool" name="psterm" subparam="true"> |
1012 1004 | <shortdescription>Use prolate spheroidal during gridding</shortdescription> |
1013 1005 | <description>Include the Prolate Spheroidal (PS) funtion as the anti-aliasing |
1014 1006 | operator in the gridding convolution functions used for gridding. |
1015 1007 | |
1016 1008 | Setting this parameter to true is necessary when aterm is set to |
1017 1009 | false. It can be set to false when aterm is set to true, though |
1018 1010 | with this setting effects of aliasing may be there in the image, |
1019 1011 | particularly near the edges. |
1020 1012 | |
1021 1013 | When set to true, the .pb images will contain the fourier transform |
1022 - | of the of the PS funtion. The table below enumarates the functional |
1023 - | effects of the psterm, aterm and wprojplanes settings. PB referes to |
1024 - | the Primary Beam and FT() refers to the Fourier transform operation. |
1025 - | |
1026 - | Operation aterm psterm wprojplanes Contents of the .pb image |
1027 - | ---------------------------------------------------------------------- |
1028 - | AW-Projection True True >1 FT(PS) x PB |
1029 - | False PB |
1030 - | |
1031 - | A-Projection True True 1 FT(PS) x PB |
1032 - | False PB |
1014 + | of the of the PS funtion. |
1033 1015 | |
1034 - | W-Projection False True >1 FT(PS) |
1016 + | For more information on the functional |
1017 + | effects of the psterm, aterm and wprojplanes settings, see the |
1018 + | 'Wide-field Imaging' pages in CASA Docs (https://casadocs.readthedocs.io). |
1035 1019 | |
1036 - | Standard False True 1 FT(PS) |
1037 1020 | |
1038 1021 | </description> |
1039 1022 | <value type="bool">False</value> |
1040 1023 | </param> |
1041 1024 | |
1042 1025 | <param type="bool" name="wbawp" subparam="true"> |
1043 1026 | <shortdescription>Use wideband A-terms</shortdescription> |
1044 - | <description>Use frequency dependent A-terms |
1027 + | <description>Use frequency dependent A-terms. |
1045 1028 | Scale aperture illumination functions appropriately with frequency |
1046 1029 | when gridding and combining data from multiple channels. |
1047 1030 | </description> |
1048 1031 | <value type="bool">True</value> |
1049 1032 | </param> |
1050 1033 | |
1051 1034 | <param type="bool" name="conjbeams" subparam="true"> |
1052 1035 | <shortdescription>Use conjugate frequency for wideband A-terms</shortdescription> |
1053 - | <description>Use conjugate frequency for wideband A-terms |
1036 + | <description>Use conjugate frequency for wideband A-terms. |
1054 1037 | |
1055 1038 | While gridding data from one frequency channel, choose a convolution |
1056 1039 | function from a 'conjugate' frequency such that the resulting baseline |
1057 1040 | primary beam is approximately constant across frequency. For a system in |
1058 1041 | which the primary beam scales with frequency, this step will eliminate |
1059 1042 | instrumental spectral structure from the measured data and leave only the |
1060 1043 | sky spectrum for the minor cycle to model and reconstruct [Bhatnagar et al., ApJ, 2013]. |
1061 1044 | |
1062 1045 | As a rough guideline for when this is relevant, a source at the half power |
1063 1046 | point of the PB at the center frequency will see an artificial spectral |
1064 1047 | index of -1.4 due to the frequency dependence of the PB [Sault and Wieringa, 1994]. |
1065 1048 | If left uncorrected during gridding, this spectral structure must be modeled |
1066 1049 | in the minor cycle (using the mtmfs algorithm) to avoid dynamic range limits |
1067 1050 | (of a few hundred for a 2:1 bandwidth). |
1068 - | This works for specmode='mfs' and its value is ignored for cubes |
1051 + | This works for specmode='mfs' and its value is ignored for cubes. |
1069 1052 | |
1070 1053 | </description> |
1071 1054 | <value type="bool">False</value> |
1072 1055 | </param> |
1073 1056 | |
1074 1057 | <param type="string" name="cfcache" subparam="true"> |
1075 1058 | <shortdescription>Convolution function cache directory name</shortdescription> |
1076 - | <description>Convolution function cache directory name |
1059 + | <description>Convolution function cache directory name. |
1077 1060 | |
1078 1061 | Name of a directory in which to store gridding convolution functions. |
1079 1062 | This cache is filled at the beginning of an imaging run. This step can be time |
1080 1063 | consuming but the cache can be reused across multiple imaging runs that |
1081 1064 | use the same image parameters (cell size, image size , spectral data |
1082 1065 | selections, wprojplanes, wbawp, psterm, aterm). The effect of the wbawp, |
1083 1066 | psterm and aterm settings is frozen-in in the cfcache. Using an existing cfcache |
1084 1067 | made with a different setting of these parameters will not reflect the current |
1085 1068 | settings. |
1086 1069 | |
1098 1081 | |
1099 1082 | <param type="bool" name="usepointing" subparam="true"> |
1100 1083 | <shortdescription>The parameter makes the gridder utilize the pointing table phase directions while computing the residual image.</shortdescription> |
1101 1084 | <description>The usepointing flag informs the gridder that it should utilize the pointing table |
1102 1085 | to use the correct direction in which the antenna is pointing with respect to the pointing phasecenter. </description> |
1103 1086 | <value type="bool">False</value> |
1104 1087 | </param> |
1105 1088 | |
1106 1089 | <param type="double" name="computepastep" subparam="true"> |
1107 1090 | <shortdescription>Parallactic angle interval after the AIFs are recomputed (deg)</shortdescription> |
1108 - | <description>Parallactic angle interval after the AIFs are recomputed (deg) |
1091 + | <description>Parallactic angle interval after the AIFs are recomputed (deg). |
1109 1092 | |
1110 1093 | This parameter controls the accuracy of the aperture illumination function |
1111 1094 | used with AProjection for alt-az mount dishes where the AIF rotates on the |
1112 1095 | sky as the synthesis image is built up. Once the PA in the data changes by |
1113 1096 | the given interval, AIFs are re-computed at the new PA. |
1114 1097 | |
1115 1098 | A value of 360.0 deg (the default) implies no re-computation due to PA rotation. |
1116 1099 | AIFs are computed for the PA value of the first valid data received and used for |
1117 1100 | all of the data. |
1118 1101 | |
1200 1183 | |
1201 1184 | </description> |
1202 1185 | <type>intVec</type><type>doubleVec</type> |
1203 1186 | <value type="doubleVec"/> |
1204 1187 | </param> |
1205 1188 | |
1206 1189 | |
1207 1190 | |
1208 1191 | <param type="double" name="pblimit" subparam="true"> |
1209 1192 | <shortdescription>PB gain level at which to cut off normalizations </shortdescription> |
1210 - | <description>PB gain level at which to cut off normalizations |
1193 + | <description>PB gain level at which to cut off normalizations. |
1211 1194 | |
1212 1195 | Divisions by .pb during normalizations have a cut off at a .pb gain |
1213 1196 | level given by pblimit. Outside this limit, image values are set to zero. |
1214 1197 | Additionally, by default, an internal T/F mask is applied to the .pb, .image and |
1215 1198 | .residual images to mask out (T) all invalid pixels outside the pblimit area. |
1216 1199 | |
1217 1200 | Note : This internal T/F mask cannot be used as a deconvolution mask. |
1218 1201 | To do so, please follow the steps listed above in the Notes for the |
1219 1202 | 'gridder' parameter. |
1220 1203 | |
1232 1215 | ia.open('test.image'); |
1233 1216 | ia.maskhandler(op='set', name=''); |
1234 1217 | ia.done() |
1235 1218 | |
1236 1219 | </description> |
1237 1220 | <value type="double">0.2</value> |
1238 1221 | </param> |
1239 1222 | |
1240 1223 | <param type="string" name="normtype" subparam="true"> |
1241 1224 | <shortdescription>Normalization type (flatnoise, flatsky,pbsquare)</shortdescription> |
1242 - | <description>Normalization type (flatnoise, flatsky, pbsquare) |
1225 + | <description>Normalization type (flatnoise, flatsky, pbsquare). |
1243 1226 | |
1244 1227 | Gridded (and FT'd) images represent the PB-weighted sky image. |
1245 1228 | Qualitatively it can be approximated as two instances of the PB |
1246 1229 | applied to the sky image (one naturally present in the data |
1247 1230 | and one introduced during gridding via the convolution functions). |
1248 1231 | |
1249 1232 | xxx.weight : Weight image approximately equal to sum ( square ( pb ) ) |
1250 1233 | xxx.pb : Primary beam calculated as sqrt ( xxx.weight ) |
1251 1234 | |
1252 1235 | normtype='flatnoise' : Divide the raw image by sqrt(.weight) so that |
1270 1253 | |
1271 1254 | |
1272 1255 | |
1273 1256 | |
1274 1257 | |
1275 1258 | |
1276 1259 | <param type="string" name="deconvolver"> |
1277 1260 | <shortdescription>Minor cycle algorithm (hogbom,clark,multiscale,mtmfs,mem,clarkstokes,asp)</shortdescription> |
1278 1261 | <description>Name of minor cycle algorithm (hogbom,clark,multiscale,mtmfs,mem,clarkstokes,asp) |
1279 1262 | |
1280 - | Each of the following algorithms operate on residual images and psfs |
1263 + | Each of the following algorithms operate on residual images and PSFs |
1281 1264 | from the gridder and produce output model and restored images. |
1282 1265 | Minor cycles stop and a major cycle is triggered when cyclethreshold |
1283 1266 | or cycleniter are reached. For all methods, components are picked from |
1284 1267 | the entire extent of the image or (if specified) within a mask. |
1285 1268 | |
1286 - | hogbom : An adapted version of Hogbom Clean [Hogbom, 1974] |
1287 - | - Find the location of the peak residual |
1288 - | - Add this delta function component to the model image |
1269 + | hogbom : An adapted version of Hogbom Clean [Hogbom, 1974]. |
1270 + | - Find the location of the peak residual. |
1271 + | - Add this delta function component to the model image. |
1289 1272 | - Subtract a scaled and shifted PSF of the same size as the image |
1290 1273 | from regions of the residual image where the two overlap. |
1291 - | - Repeat |
1274 + | - Repeat. |
1292 1275 | |
1293 - | clark : An adapted version of Clark Clean [Clark, 1980] |
1294 - | - Find the location of max(I^2+Q^2+U^2+V^2) |
1295 - | - Add delta functions to each stokes plane of the model image |
1276 + | clark : An adapted version of Clark Clean [Clark, 1980]. |
1277 + | - Find the location of max(I^2+Q^2+U^2+V^2). |
1278 + | - Add delta functions to each stokes plane of the model image. |
1296 1279 | - Subtract a scaled and shifted PSF within a small patch size |
1297 1280 | from regions of the residual image where the two overlap. |
1298 1281 | - After several iterations trigger a Clark major cycle to subtract |
1299 1282 | components from the visibility domain, but without de-gridding. |
1300 - | - Repeat |
1283 + | - Repeat. |
1301 1284 | |
1302 1285 | ( Note : 'clark' maps to imagermode='' in the old clean task. |
1303 1286 | 'clark_exp' is another implementation that maps to |
1304 1287 | imagermode='mosaic' or 'csclean' in the old clean task |
1305 1288 | but the behavior is not identical. For now, please |
1306 1289 | use deconvolver='hogbom' if you encounter problems. ) |
1307 1290 | |
1308 - | clarkstokes : Clark Clean operating separately per Stokes plane |
1291 + | clarkstokes : Clark Clean operating separately per Stokes plane. |
1309 1292 | |
1310 1293 | (Note : 'clarkstokes_exp' is an alternate version. See above.) |
1311 1294 | |
1312 - | multiscale : MultiScale Clean [Cornwell, 2008] |
1313 - | - Smooth the residual image to multiple scale sizes |
1314 - | - Find the location and scale at which the peak occurs |
1315 - | - Add this multiscale component to the model image |
1295 + | multiscale : MultiScale Clean [Cornwell, 2008]. |
1296 + | - Smooth the residual image to multiple scale sizes. |
1297 + | - Find the location and scale at which the peak occurs. |
1298 + | - Add this multiscale component to the model image. |
1316 1299 | - Subtract a scaled,smoothed,shifted PSF (within a small |
1317 - | patch size per scale) from all residual images |
1318 - | - Repeat from step 2 |
1300 + | patch size per scale) from all residual images. |
1301 + | - Repeat from step 2. |
1319 1302 | |
1320 - | mtmfs : Multi-term (Multi Scale) Multi-Frequency Synthesis [Rau and Cornwell, 2011] |
1321 - | - Smooth each Taylor residual image to multiple scale sizes |
1303 + | mtmfs : Multi-term (Multi Scale) Multi-Frequency Synthesis [Rau and Cornwell, 2011]. |
1304 + | - Smooth each Taylor residual image to multiple scale sizes. |
1322 1305 | - Solve a NTxNT system of equations per scale size to compute |
1323 - | Taylor coefficients for components at all locations |
1306 + | Taylor coefficients for components at all locations. |
1324 1307 | - Compute gradient chi-square and pick the Taylor coefficients |
1325 1308 | and scale size at the location with maximum reduction in |
1326 - | chi-square |
1309 + | chi-square. |
1327 1310 | - Add multi-scale components to each Taylor-coefficient |
1328 - | model image |
1311 + | model image. |
1329 1312 | - Subtract scaled,smoothed,shifted PSF (within a small patch size |
1330 - | per scale) from all smoothed Taylor residual images |
1331 - | - Repeat from step 2 |
1313 + | per scale) from all smoothed Taylor residual images. |
1314 + | - Repeat from step 2. |
1332 1315 | |
1333 1316 | |
1334 - | mem : Maximum Entropy Method [Cornwell and Evans, 1985] |
1317 + | mem : Maximum Entropy Method [Cornwell and Evans, 1985]. |
1335 1318 | - Iteratively solve for values at all individual pixels via the |
1336 1319 | MEM method. It minimizes an objective function of |
1337 1320 | chi-square plus entropy (here, a measure of difference |
1338 1321 | between the current model and a flat prior model). |
1339 1322 | |
1340 1323 | (Note : This MEM implementation is not very robust. |
1341 1324 | Improvements will be made in the future.) |
1342 1325 | |
1343 - | asp : Adaptive Scale Pixel algorithm [Bhatnagar and Cornwell, 2004] |
1344 - | - Define a set of initial scales defined as 0, W, 2W 4W and 8W |
1345 - | where W is a 2D Gaussian fitting width to the PSF |
1346 - | - Smooth the residual image by a Gaussian beam at initial scales |
1347 - | - Search for the global peak (F) among these smoothed residual images |
1348 - | - form an active Aspen set: amplitude(F), amplitude location(x,y) |
1326 + | asp : Adaptive Scale Pixel algorithm [Bhatnagar and Cornwell, 2004]. |
1327 + | - Define a set of initial scales defined as 0, W, 2W 4W and 8W. |
1328 + | where W is a 2D Gaussian fitting width to the PSF. |
1329 + | - Smooth the residual image by a Gaussian beam at initial scales. |
1330 + | - Search for the global peak (F) among these smoothed residual images. |
1331 + | - form an active Aspen set: amplitude(F), amplitude location(x,y). |
1349 1332 | - Optimize the Aspen set by minimizing the objective function RI-Aspen*PSF, |
1350 1333 | where RI is the residual image and * is the convulition operation. |
1351 - | - Compute the model image and update the residual image |
1352 - | - Repeat from step 2 |
1334 + | - Compute the model image and update the residual image. |
1335 + | - Repeat from step 2. |
1353 1336 | |
1354 1337 | (Note : This is an experimental version of the ASP algorithm.) |
1355 1338 | |
1356 1339 | |
1357 1340 | |
1358 1341 | |
1359 1342 | </description> |
1360 1343 | <value type="string">hogbom</value> |
1361 1344 | <allowed kind="enum"> |
1362 1345 | <value>hogbom</value> |
1374 1357 | |
1375 1358 | <param type="any" name="scales" subparam="true"> |
1376 1359 | <shortdescription>List of scale sizes (in pixels) for multi-scale algorithms</shortdescription> |
1377 1360 | <description>List of scale sizes (in pixels) for multi-scale and mtmfs algorithms. |
1378 1361 | --> scales=[0,6,20] |
1379 1362 | This set of scale sizes should represent the sizes |
1380 1363 | (diameters in units of number of pixels) |
1381 1364 | of dominant features in the image being reconstructed. |
1382 1365 | |
1383 1366 | The smallest scale size is recommended to be 0 (point source), |
1384 - | the second the size of the synthesized beam and the third 3-5 |
1367 + | the second being the size of the synthesized beam and the third being 3-5 |
1385 1368 | times the synthesized beam, etc. For example, if the synthesized |
1386 1369 | beam is 10" FWHM and cell=2",try scales = [0,5,15]. |
1387 1370 | |
1388 1371 | For numerical stability, the largest scale must be |
1389 1372 | smaller than the image (or mask) size and smaller than or |
1390 1373 | comparable to the scale corresponding to the lowest measured |
1391 1374 | spatial frequency (as a scale size much larger than what the |
1392 1375 | instrument is sensitive to is unconstrained by the data making |
1393 - | it harder to recovery from errors during the minor cycle). |
1376 + | it harder to recover from errors during the minor cycle). |
1394 1377 | </description> |
1395 1378 | <type>intVec</type><type>doubleVec</type> |
1396 1379 | <value type="intVec"/> |
1397 1380 | </param> |
1398 1381 | |
1399 1382 | <param type="int" name="nterms" subparam="true"> |
1400 1383 | <shortdescription>Number of Taylor coefficients in the spectral model</shortdescription> |
1401 - | <description>Number of Taylor coefficients in the spectral model |
1384 + | <description>Number of Taylor coefficients in the spectral model. |
1402 1385 | |
1403 - | - nterms=1 : Assume flat spectrum source |
1404 - | - nterms=2 : Spectrum is a straight line with a slope |
1405 - | - nterms=N : A polynomial of order N-1 |
1386 + | - nterms=1 : Assume flat spectrum source. |
1387 + | - nterms=2 : Spectrum is a straight line with a slope. |
1388 + | - nterms=N : A polynomial of order N-1. |
1406 1389 | |
1407 1390 | From a Taylor expansion of the expression of a power law, the |
1408 - | spectral index is derived as alpha = taylorcoeff_1 / taylorcoeff_0 |
1391 + | spectral index is derived as alpha = taylorcoeff_1 / taylorcoeff_0. |
1409 1392 | |
1410 1393 | Spectral curvature is similarly derived when possible. |
1411 1394 | |
1412 1395 | The optimal number of Taylor terms depends on the available |
1413 1396 | signal to noise ratio, bandwidth ratio, and spectral shape of the |
1414 1397 | source as seen by the telescope (sky spectrum x PB spectrum). |
1415 1398 | |
1416 1399 | nterms=2 is a good starting point for wideband EVLA imaging |
1417 1400 | and the lower frequency bands of ALMA (when fractional bandwidth |
1418 1401 | is greater than 10%) and if there is at least one bright source for |
1431 1414 | - These alpha, alpha.error and beta images contain |
1432 1415 | internal T/F masks based on a threshold computed |
1433 1416 | as peakresidual/10. Additional masking based on |
1434 1417 | .alpha/.alpha.error may be desirable. |
1435 1418 | - .alpha.error is a purely empirical estimate derived |
1436 1419 | from the propagation of error during the division of |
1437 1420 | two noisy numbers (alpha = xx.tt1/xx.tt0) where the |
1438 1421 | 'error' on tt1 and tt0 are simply the values picked from |
1439 1422 | the corresponding residual images. The absolute value |
1440 1423 | of the error is not always accurate and it is best to interpret |
1441 - | the errors across the image only in a relative sense.) |
1424 + | the errors across the image only in a relative sense. |
1442 1425 | |
1443 1426 | |
1444 1427 | </description> |
1445 1428 | <value type="int">2</value> |
1446 1429 | </param> |
1447 1430 | |
1448 1431 | <param type="double" name="smallscalebias" subparam="true"> |
1449 1432 | <shortdescription>Biases the scale selection when using multi-scale or mtmfs deconvolvers </shortdescription> |
1450 1433 | <description>A numerical control to bias the scales when using multi-scale or mtmfs algorithms. |
1451 1434 | The peak from each scale's smoothed residual is |
1456 1439 | A score of 0.0 gives all scales equal weight (default). |
1457 1440 | A score larger than 0.0 will bias the solution towards smaller scales. |
1458 1441 | A score smaller than 0.0 will bias the solution towards larger scales. |
1459 1442 | The effect of smallscalebias is more pronounced when using multi-scale relative to mtmfs. |
1460 1443 | </description> |
1461 1444 | <value type="double">0.0</value> |
1462 1445 | </param> |
1463 1446 | |
1464 1447 | <param type="double" name="fusedthreshold" subparam="true"> |
1465 1448 | <shortdescription>Threshold for triggering Hogbom Clean </shortdescription> |
1466 - | <description> Threshold for triggering Hogbom Clean (number in units of Jy) |
1449 + | <description> Threshold for triggering Hogbom Clean (number in units of Jy). |
1467 1450 | |
1468 - | fusedthreshold = 0.0001 : 0.1 mJy |
1451 + | fusedthreshold = 0.0001 : 0.1 mJy. |
1469 1452 | |
1470 1453 | This is a subparameter of the Asp Clean deconvolver. When peak residual |
1471 1454 | is lower than the threshold, Asp Clean is "switched to Hogbom Clean" (i.e. only use the 0 scale for cleaning) for |
1472 1455 | the following number of iterations until it switches back to Asp Clean. |
1473 1456 | |
1474 1457 | NumberIterationsInHogbom = 50 + 2 * (exp(0.05 * NthHogbom) - 1) |
1475 1458 | |
1476 1459 | , where NthHogbom is the number of times Hogbom Clean has been triggered. |
1477 1460 | |
1478 1461 | When the Asp Clean detects it is approaching convergence, it uses only the 0 scale for the following number of iterations for better computational efficiency. |
1523 1506 | |
1524 1507 | </description> |
1525 1508 | <value type="bool">True</value> |
1526 1509 | </param> |
1527 1510 | |
1528 1511 | |
1529 1512 | <param type="any" name="restoringbeam" subparam="true"> |
1530 1513 | <shortdescription>Restoring beam shape to use. Default is the PSF main lobe</shortdescription> |
1531 1514 | <description> Restoring beam shape/size to use. |
1532 1515 | |
1533 - | - restoringbeam='' or [''] |
1516 + | - restoringbeam='' or ['']. |
1534 1517 | A Gaussian fitted to the PSF main lobe (separately per image plane). |
1535 1518 | |
1536 - | - restoringbeam='10.0arcsec' |
1537 - | Use a circular Gaussian of this width for all planes |
1519 + | - restoringbeam='10.0arcsec'. |
1520 + | Use a circular Gaussian of this width for all planes. |
1538 1521 | |
1539 - | - restoringbeam=['8.0arcsec','10.0arcsec','45deg'] |
1540 - | Use this elliptical Gaussian for all planes |
1522 + | - restoringbeam=['8.0arcsec','10.0arcsec','45deg']. |
1523 + | Use this elliptical Gaussian for all planes. |
1541 1524 | |
1542 - | - restoringbeam='common' |
1525 + | - restoringbeam='common'. |
1543 1526 | Automatically estimate a common beam shape/size appropriate for |
1544 - | all planes. |
1527 + | all planes. This option can be used when the beam shape is different as a function of frequency, and will smooth all planes to a single beam, defined by the largest beam in the cube. |
1545 1528 | |
1546 1529 | Note : For any restoring beam different from the native resolution |
1547 1530 | the model image is convolved with the beam and added to |
1548 1531 | residuals that have been convolved to the same target resolution. |
1549 1532 | |
1550 1533 | </description> |
1551 1534 | <type>string</type><type>stringVec</type> |
1552 1535 | <value type="stringVec"/> |
1553 1536 | </param> |
1554 1537 | |
1555 1538 | <param type="bool" name="pbcor" subparam="true"> |
1556 1539 | <shortdescription>Apply PB correction on the output restored image</shortdescription> |
1557 - | <description> Apply PB correction on the output restored image |
1540 + | <description> Apply PB correction on the output restored image. |
1558 1541 | |
1559 1542 | A new image with extension .image.pbcor will be created from |
1560 1543 | the evaluation of .image / .pb for all pixels above the specified pblimit. |
1561 1544 | |
1562 1545 | Note : Stand-alone PB-correction can be triggered by re-running |
1563 1546 | tclean with the appropriate imagename and with |
1564 1547 | niter=0, calcpsf=False, calcres=False, pbcor=True, vptable='vp.tab' |
1565 - | ( where vp.tab is the name of the vpmanager file. |
1566 - | See the inline help for the 'vptable' parameter ) |
1548 + | ( where vp.tab is the name of the vpmanager file; |
1549 + | see the inline help for the 'vptable' parameter ). Alternatively, task impbcor can be used for primary beam correction using the .image and .pb files. |
1567 1550 | |
1568 1551 | Note : For deconvolver='mtmfs', pbcor will divide each Taylor term image by the .tt0 average PB. |
1569 1552 | For all gridders, this calculation is accurate for small fractional bandwidths. |
1570 1553 | |
1571 1554 | For large fractional bandwidths, please use one of the following options. |
1572 1555 | |
1573 1556 | (a) For single pointings, run the tclean task with specmode='mfs', deconvolver='mtmfs', |
1574 1557 | and gridder='standard' with pbcor=True or False. |
1575 1558 | If a PB-corrected spectral index is required, |
1576 1559 | please use the widebandpbcor task to apply multi-tern PB-correction. |
1597 1580 | </description> |
1598 1581 | <value type="bool">False</value> |
1599 1582 | </param> |
1600 1583 | |
1601 1584 | |
1602 1585 | |
1603 1586 | |
1604 1587 | |
1605 1588 | <param type="string" name="outlierfile"> |
1606 1589 | <shortdescription>Name of outlier-field image definitions</shortdescription> |
1607 - | <description>Name of outlier-field image definitions |
1590 + | <description>Name of outlier-field image definitions. |
1608 1591 | |
1609 1592 | A text file containing sets of parameter=value pairs, |
1610 1593 | one set per outlier field. |
1611 1594 | |
1612 1595 | Example : outlierfile='outs.txt' |
1613 1596 | |
1614 1597 | Contents of outs.txt : |
1615 1598 | |
1616 1599 | imagename=tst1 |
1617 1600 | nchan=1 |
1627 1610 | phasecenter=J2000 19:58:40.895 +40.56.00.000 |
1628 1611 | mask=circle[[60pix,60pix],20pix] |
1629 1612 | |
1630 1613 | The following parameters are currently allowed to be different between |
1631 1614 | the main field and the outlier fields (i.e. they will be recognized if found |
1632 1615 | in the outlier text file). If a parameter is not listed, the value is picked from |
1633 1616 | what is defined in the main task input. |
1634 1617 | |
1635 1618 | imagename, imsize, cell, phasecenter, startmodel, mask |
1636 1619 | specmode, nchan, start, width, nterms, reffreq, |
1637 - | gridder, deconvolver, wprojplanes |
1620 + | gridder, deconvolver, wprojplanes. |
1638 1621 | |
1639 1622 | Note : 'specmode' is an option, so combinations of mfs and cube |
1640 1623 | for different image fields, for example, are supported. |
1641 1624 | 'deconvolver' and 'gridder' are also options that allow different |
1642 1625 | imaging or deconvolution algorithm per image field. |
1643 1626 | |
1644 1627 | For example, multiscale with wprojection and 16 w-term planes |
1645 1628 | on the main field and mtmfs with nterms=3 and wprojection |
1646 1629 | with 64 planes on a bright outlier source for which the frequency |
1647 1630 | dependence of the primary beam produces a strong effect that |
1648 1631 | must be modeled. The traditional alternative to this approach is |
1649 1632 | to first image the outlier, subtract it out of the data (uvsub) and |
1650 1633 | then image the main field. |
1651 1634 | |
1652 - | Note : If you encounter a use-case where some other parameter needs |
1653 - | to be allowed in the outlier file (and it is logical to do so), please |
1654 - | send us feedback. The above is an initial list. |
1655 1635 | |
1656 1636 | </description> |
1657 1637 | <value type="string"/> |
1658 1638 | </param> |
1659 1639 | |
1660 1640 | |
1661 1641 | |
1662 1642 | |
1663 1643 | |
1664 1644 | |
1665 1645 | <param type="string" name="weighting"> |
1666 1646 | <shortdescription>Weighting scheme (natural,uniform,briggs, superuniform, radial, briggsabs[experimental], briggsbwtaper[experimental])</shortdescription> |
1667 - | <description>Weighting scheme (natural,uniform,briggs,superuniform,radial, briggsabs, briggsbwtaper) |
1647 + | <description>Weighting scheme (natural,uniform,briggs,superuniform,radial, briggsabs, briggsbwtaper). |
1668 1648 | |
1669 1649 | During gridding of the dirty or residual image, each visibility value is |
1670 1650 | multiplied by a weight before it is accumulated on the uv-grid. |
1671 1651 | The PSF's uv-grid is generated by gridding only the weights (weightgrid). |
1672 1652 | |
1673 1653 | weighting='natural' : Gridding weights are identical to the data weights |
1674 1654 | from the MS. For visibilities with similar data weights, |
1675 1655 | the weightgrid will follow the sample density |
1676 1656 | pattern on the uv-plane. This weighting scheme |
1677 1657 | provides the maximum imaging sensitivity at the |
1678 - | expense of a possibly fat PSF with high sidelobes. |
1658 + | expense of a PSF with possibly wider main lobes and high sidelobes. |
1679 1659 | It is most appropriate for detection experiments |
1680 1660 | where sensitivity is most important. |
1681 1661 | |
1682 1662 | weighting='uniform' : Gridding weights per visibility data point are the |
1683 1663 | original data weights divided by the total weight of |
1684 1664 | all data points that map to the same uv grid cell : |
1685 1665 | ' data_weight / total_wt_per_cell '. |
1686 1666 | |
1687 1667 | The weightgrid is as close to flat as possible resulting |
1688 1668 | in a PSF with a narrow main lobe and suppressed |
1770 1750 | |
1771 1751 | <param type="any" name="noise" subparam="true"><shortdescription>noise parameter for briggs abs mode weighting</shortdescription><description>noise parameter for briggs abs mode weighting</description> |
1772 1752 | |
1773 1753 | <any type="variant"/> |
1774 1754 | <value type="string">1.0Jy</value> |
1775 1755 | </param> |
1776 1756 | |
1777 1757 | <param type="int" name="npixels" subparam="true"> |
1778 1758 | <shortdescription>Number of pixels to determine uv-cell size </shortdescription> |
1779 1759 | <description>Number of pixels to determine uv-cell size for super-uniform weighting |
1780 - | (0 defaults to -/+ 3 pixels) |
1760 + | (0 defaults to -/+ 3 pixels). |
1781 1761 | |
1782 1762 | npixels -- uv-box used for weight calculation |
1783 1763 | a box going from -npixel/2 to +npixel/2 on each side |
1784 1764 | around a point is used to calculate weight density. |
1785 1765 | |
1786 1766 | npixels=2 goes from -1 to +1 and covers 3 pixels on a side. |
1787 1767 | |
1788 1768 | npixels=0 implies a single pixel, which does not make sense for |
1789 1769 | superuniform weighting. Therefore, for 'superuniform' |
1790 1770 | weighting, if npixels=0 it will be forced to 6 (or a box |
1791 1771 | of -3pixels to +3pixels) to cover 7 pixels on a side. |
1792 1772 | |
1793 1773 | </description> |
1794 1774 | <value type="int">0</value> |
1795 1775 | </param> |
1796 1776 | |
1797 1777 | |
1798 1778 | |
1799 1779 | <param type="stringVec" name="uvtaper" subparam="true"> |
1800 1780 | <shortdescription>uv-taper on outer baselines in uv-plane</shortdescription> |
1801 - | <description>uv-taper on outer baselines in uv-plane |
1781 + | <description>uv-taper on outer baselines in uv-plane. |
1802 1782 | |
1803 1783 | Apply a Gaussian taper in addition to the weighting scheme specified |
1804 1784 | via the 'weighting' parameter. Higher spatial frequencies are weighted |
1805 1785 | down relative to lower spatial frequencies to suppress artifacts |
1806 1786 | arising from poorly sampled areas of the uv-plane. It is equivalent to |
1807 1787 | smoothing the PSF obtained by other weighting schemes and can be |
1808 1788 | specified either as the HWHM of a Gaussian in uv-space (eg. units of lambda) |
1809 1789 | or as the FWHM of a Gaussian in the image domain (eg. angular units like arcsec). |
1810 1790 | |
1811 - | uvtaper = [bmaj, bmin, bpa] |
1791 + | uvtaper = [bmaj, bmin, bpa]. |
1812 1792 | |
1813 - | Note : FWHM_uv_lambda = (4 log2) / ( pi * FWHM_lm_radians ) |
1793 + | Note : FWHM_uv_lambda = (4 log2) / ( pi * FWHM_lm_radians ). |
1814 1794 | |
1815 - | A FWHM_lm of 100.000 arcsec maps to a HWHM_uv of 910.18 lambda |
1816 - | A FWHM_lm of 1 arcsec maps to a HWHM_uv of 91 klambda |
1795 + | A FWHM_lm of 100.000 arcsec maps to a HWHM_uv of 910.18 lambda. |
1796 + | A FWHM_lm of 1 arcsec maps to a HWHM_uv of 91 klambda. |
1817 1797 | |
1818 - | default: uvtaper=[]; no Gaussian taper applied |
1819 - | example: uvtaper=['5klambda'] circular taper of HWHM=5 kilo-lambda |
1820 - | uvtaper=['5klambda','3klambda','45.0deg'] uv-domain HWHM |
1821 - | uvtaper=['50arcsec','30arcsec','30.0deg'] : image domain FWHM |
1822 - | uvtaper=['10arcsec'] : image domain FWHM |
1823 - | uvtaper=['300.0'] default units are lambda in aperture plane |
1798 + | default: uvtaper=[]; no Gaussian taper applied. |
1799 + | example: uvtaper=['5klambda'] circular taper of HWHM=5 kilo-lambda. |
1800 + | uvtaper=['5klambda','3klambda','45.0deg'] uv-domain HWHM. |
1801 + | uvtaper=['50arcsec','30arcsec','30.0deg'] : image domain FWHM. |
1802 + | uvtaper=['10arcsec'] : image domain FWHM. |
1803 + | uvtaper=['300.0'] default units are lambda in aperture plane. |
1824 1804 | |
1825 1805 | </description> |
1826 1806 | <value type="vector"> |
1827 1807 | <value/> |
1828 1808 | </value> |
1829 1809 | </param> |
1830 1810 | |
1831 1811 | |
1832 1812 | |
1833 1813 | |
1834 1814 | |
1835 1815 | |
1836 1816 | |
1837 1817 | |
1838 1818 | |
1839 1819 | <param type="int" name="niter"> |
1840 1820 | <shortdescription>Maximum number of iterations</shortdescription> |
1841 - | <description>Maximum number of iterations |
1821 + | <description>Maximum number of iterations. |
1842 1822 | |
1843 1823 | A stopping criterion based on total iteration count. |
1844 1824 | Currently the parameter type is defined as an integer therefore the integer value |
1845 1825 | larger than 2147483647 will not be set properly as it causes an overflow. |
1846 1826 | |
1847 1827 | Iterations are typically defined as the selecting one flux component |
1848 1828 | and partially subtracting it out from the residual image. |
1849 1829 | |
1850 - | niter=0 : Do only the initial major cycle (make dirty image, psf, pb, etc) |
1830 + | niter=0 : Do only the initial major cycle (make dirty image, psf, pb, etc). |
1851 1831 | |
1852 1832 | niter larger than zero : Run major and minor cycles. |
1853 1833 | |
1854 - | Note : Global stopping criteria vs major-cycle triggers |
1834 + | Note : Global stopping criteria vs major-cycle triggers. |
1855 1835 | |
1856 1836 | In addition to global stopping criteria, the following rules are |
1857 1837 | used to determine when to terminate a set of minor cycle iterations |
1858 - | and trigger major cycles [derived from Cotton-Schwab Clean, 1984] |
1838 + | and trigger major cycles [derived from Cotton-Schwab Clean, 1984]. |
1859 1839 | |
1860 1840 | 'cycleniter' : controls the maximum number of iterations per image |
1861 1841 | plane before triggering a major cycle. |
1862 1842 | 'cyclethreshold' : Automatically computed threshold related to the |
1863 1843 | max sidelobe level of the PSF and peak residual. |
1864 1844 | Divergence, detected as an increase of 10% in peak residual from the |
1865 - | minimum so far (during minor cycle iterations) |
1845 + | minimum so far (during minor cycle iterations). |
1866 1846 | |
1867 1847 | The first criterion to be satisfied takes precedence. |
1868 1848 | |
1869 1849 | Note : Iteration counts for cubes or multi-field images : |
1870 1850 | For images with multiple planes (or image fields) on which the |
1871 1851 | deconvolver operates in sequence, iterations are counted across |
1872 1852 | all planes (or image fields). The iteration count is compared with |
1873 1853 | 'niter' only after all channels/planes/fields have completed their |
1874 1854 | minor cycles and exited either due to 'cycleniter' or 'cyclethreshold'. |
1875 1855 | Therefore, the actual number of iterations reported in the logger |
1876 1856 | can sometimes be larger than the user specified value in 'niter'. |
1877 1857 | For example, with niter=100, cycleniter=20,nchan=10,threshold=0, |
1878 1858 | a total of 200 iterations will be done in the first set of minor cycles |
1879 1859 | before the total is compared with niter=100 and it exits. |
1880 1860 | |
1881 - | Note : Additional global stopping criteria include |
1882 - | - no change in peak residual across two major cycles |
1883 - | - a 50% or more increase in peak residual across one major cycle |
1861 + | Note : Additional global stopping criteria include: |
1862 + | - no change in peak residual across two major cycles. |
1863 + | - a 50% or more increase in peak residual across one major cycle. |
1884 1864 | |
1885 1865 | |
1886 1866 | </description> |
1887 1867 | <value type="int">0</value> |
1888 1868 | </param> |
1889 1869 | |
1890 1870 | <param type="double" name="gain" subparam="true"> |
1891 1871 | <shortdescription>Loop gain</shortdescription> |
1892 - | <description>Loop gain |
1872 + | <description>Loop gain. |
1893 1873 | |
1894 1874 | Fraction of the source flux to subtract out of the residual image |
1895 1875 | for the CLEAN algorithm and its variants. |
1896 1876 | |
1897 1877 | A low value (0.2 or less) is recommended when the sky brightness |
1898 1878 | distribution is not well represented by the basis functions used by |
1899 1879 | the chosen deconvolution algorithm. A higher value can be tried when |
1900 1880 | there is a good match between the true sky brightness structure and |
1901 1881 | the basis function shapes. For example, for extended emission, |
1902 1882 | multiscale clean with an appropriate set of scale sizes will tolerate |
1903 - | a higher loop gain than Clark clean (for example). |
1883 + | a higher loop gain than Clark clean. |
1904 1884 | |
1905 1885 | |
1906 1886 | |
1907 1887 | </description> |
1908 1888 | <value type="double">0.1</value> |
1909 1889 | </param> |
1910 1890 | |
1911 1891 | <param type="any" name="threshold" subparam="true"> |
1912 1892 | <shortdescription>Stopping threshold </shortdescription> |
1913 - | <description>Stopping threshold (number in units of Jy, or string) |
1893 + | <description>Stopping threshold (number in units of Jy, or string). |
1914 1894 | |
1915 1895 | A global stopping threshold that the peak residual (within clean mask) |
1916 1896 | across all image planes is compared to. |
1917 1897 | |
1918 1898 | threshold = 0.005 : 5mJy |
1919 1899 | threshold = '5.0mJy' |
1920 1900 | |
1921 1901 | Note : A 'cyclethreshold' is internally computed and used as a major cycle |
1922 - | trigger. It is related what fraction of the PSF can be reliably |
1902 + | trigger. It is related to what fraction of the PSF can be reliably |
1923 1903 | used during minor cycle updates of the residual image. By default |
1924 1904 | the minor cycle iterations terminate once the peak residual reaches |
1925 1905 | the first sidelobe level of the brightest source. |
1926 1906 | |
1927 1907 | 'cyclethreshold' is computed as follows using the settings in |
1928 1908 | parameters 'cyclefactor','minpsffraction','maxpsffraction','threshold' : |
1929 1909 | |
1930 1910 | psf_fraction = max_psf_sidelobe_level \* 'cyclefactor' |
1931 1911 | psf_fraction = max(psf_fraction, 'minpsffraction'); |
1932 1912 | psf_fraction = min(psf_fraction, 'maxpsffraction'); |
1933 1913 | cyclethreshold = peak_residual \* psf_fraction |
1934 1914 | cyclethreshold = max( cyclethreshold, 'threshold' ) |
1935 1915 | |
1936 1916 | If nsigma is set (>0.0), the N-sigma threshold is calculated (see |
1937 1917 | the description under nsigma), then cyclethreshold is further modified as, |
1938 1918 | |
1939 - | cyclethreshold = max( cyclethreshold, nsgima_threshold ) |
1919 + | cyclethreshold = max( cyclethreshold, nsgima_threshold ). |
1940 1920 | |
1941 1921 | |
1942 1922 | 'cyclethreshold' is made visible and editable only in the |
1943 1923 | interactive GUI when tclean is run with interactive=True. |
1944 1924 | </description> |
1945 1925 | |
1946 1926 | <value type="double">0.0</value> |
1947 1927 | </param> |
1948 1928 | |
1949 1929 | <param type="double" name="nsigma" subparam="true"> |
1950 1930 | <shortdescription>Multiplicative factor for rms-based threshold stopping</shortdescription> |
1951 - | <description>Multiplicative factor for rms-based threshold stopping |
1931 + | <description>Multiplicative factor for rms-based threshold stopping. |
1952 1932 | |
1953 1933 | N-sigma threshold is calculated as nsigma \* rms value per image plane determined |
1954 1934 | from a robust statistics. For nsigma > 0.0, in a minor cycle, a maximum of the two values, |
1955 1935 | the N-sigma threshold and cyclethreshold, is used to trigger a major cycle |
1956 1936 | (see also the descreption under 'threshold'). |
1957 1937 | Set nsigma=0.0 to preserve the previous tclean behavior without this feature. |
1958 1938 | The top level parameter, fastnoise is relevant for the rms noise calculation which is used |
1959 1939 | to determine the threshold. |
1960 1940 | |
1961 1941 | The parameter 'nsigma' may be an int, float, or a double. |
1962 1942 | |
1963 1943 | </description> |
1964 1944 | <value type="double">0.0</value> |
1965 1945 | </param> |
1966 1946 | |
1967 1947 | <param type="int" name="cycleniter" subparam="true"> |
1968 1948 | <shortdescription>Maximum number of minor-cycle iterations</shortdescription> |
1969 1949 | <description>Maximum number of minor-cycle iterations (per plane) before triggering |
1970 - | a major cycle |
1950 + | a major cycle. |
1971 1951 | |
1972 1952 | For example, for a single plane image, if niter=100 and cycleniter=20, |
1973 1953 | there will be 5 major cycles after the initial one (assuming there is no |
1974 1954 | threshold based stopping criterion). At each major cycle boundary, if |
1975 1955 | the number of iterations left over (to reach niter) is less than cycleniter, |
1976 1956 | it is set to the difference. |
1977 1957 | |
1978 1958 | Note : cycleniter applies per image plane, even if cycleniter x nplanes |
1979 1959 | gives a total number of iterations greater than 'niter'. This is to |
1980 1960 | preserve consistency across image planes within one set of minor |
1981 1961 | cycle iterations. |
1982 1962 | |
1983 1963 | </description> |
1984 1964 | <value type="int">-1</value> |
1985 1965 | </param> |
1986 1966 | |
1987 1967 | <param type="double" name="cyclefactor" subparam="true"> |
1988 1968 | <shortdescription>Scaling on PSF sidelobe level to compute the minor-cycle stopping threshold.</shortdescription> |
1989 1969 | <description>Scaling on PSF sidelobe level to compute the minor-cycle stopping threshold. |
1990 1970 | |
1991 1971 | Please refer to the Note under the documentation for 'threshold' that |
1992 - | discussed the calculation of 'cyclethreshold' |
1972 + | discussed the calculation of 'cyclethreshold'. |
1993 1973 | |
1994 1974 | cyclefactor=1.0 results in a cyclethreshold at the first sidelobe level of |
1995 1975 | the brightest source in the residual image before the minor cycle starts. |
1996 1976 | |
1997 1977 | cyclefactor=0.5 allows the minor cycle to go deeper. |
1998 1978 | cyclefactor=2.0 triggers a major cycle sooner. |
1999 1979 | |
2000 1980 | </description> |
2001 1981 | <value type="double">1.0</value> |
2002 1982 | </param> |
2003 1983 | |
2004 1984 | <param type="double" name="minpsffraction" subparam="true"> |
2005 1985 | <shortdescription>PSF fraction that marks the max depth of cleaning in the minor cycle</shortdescription> |
2006 - | <description>PSF fraction that marks the max depth of cleaning in the minor cycle |
1986 + | <description>PSF fraction that marks the max depth of cleaning in the minor cycle. |
2007 1987 | |
2008 1988 | Please refer to the Note under the documentation for 'threshold' that |
2009 - | discussed the calculation of 'cyclethreshold' |
1989 + | discussed the calculation of 'cyclethreshold'. |
2010 1990 | |
2011 1991 | For example, minpsffraction=0.5 will stop cleaning at half the height of |
2012 1992 | the peak residual and trigger a major cycle earlier. |
2013 1993 | |
2014 1994 | </description> |
2015 1995 | <value type="double">0.05</value> |
2016 1996 | </param> |
2017 1997 | |
2018 1998 | <param type="double" name="maxpsffraction" subparam="true"> |
2019 1999 | <shortdescription>PSF fraction that marks the minimum depth of cleaning in the minor cycle </shortdescription> |
2020 - | <description>PSF fraction that marks the minimum depth of cleaning in the minor cycle |
2000 + | <description>PSF fraction that marks the minimum depth of cleaning in the minor cycle. |
2021 2001 | |
2022 2002 | Please refer to the Note under the documentation for 'threshold' that |
2023 - | discussed the calculation of 'cyclethreshold' |
2003 + | discussed the calculation of 'cyclethreshold'. |
2024 2004 | |
2025 2005 | For example, maxpsffraction=0.8 will ensure that at least the top 20 |
2026 2006 | percent of the source will be subtracted out in the minor cycle even if |
2027 2007 | the first PSF sidelobe is at the 0.9 level (an extreme example), or if the |
2028 2008 | cyclefactor is set too high for anything to get cleaned. |
2029 2009 | |
2030 2010 | </description> |
2031 2011 | <value type="double">0.8</value> |
2032 2012 | </param> |
2033 2013 | |
2034 2014 | |
2035 2015 | <param type="bool" name="interactive" subparam="true"> |
2036 2016 | <shortdescription>Modify masks and parameters at runtime</shortdescription> |
2037 - | <description>Modify masks and parameters at runtime |
2017 + | <description>Modify masks and parameters at runtime. |
2038 2018 | |
2039 2019 | interactive=True will trigger an interactive GUI at every major cycle |
2040 2020 | boundary (after the major cycle and before the minor cycle). |
2041 2021 | |
2042 2022 | Options for runtime parameter modification are : |
2043 2023 | |
2044 2024 | Interactive clean mask : Draw a 1/0 mask (appears as a contour) by hand. |
2045 2025 | If a mask is supplied at the task interface or if |
2046 2026 | automasking is invoked, the current mask is |
2047 2027 | displayed in the GUI and is available for manual |
2048 2028 | editing. |
2049 2029 | |
2050 2030 | Note : If a mask contour is not visible, please |
2051 2031 | check the cursor display at the bottom of |
2052 2032 | GUI to see which parts of the mask image |
2053 2033 | have ones and zeros. If the entire mask=1 |
2054 2034 | no contours will be visible. |
2055 2035 | |
2056 2036 | |
2057 - | Operation buttons : -- Stop execution now (restore current model and exit) |
2037 + | Operation buttons : -- Stop execution now (restore current model and exit). |
2058 2038 | -- Continue on until global stopping criteria are reached |
2059 - | without stopping for any more interaction |
2039 + | without stopping for any more interaction. |
2060 2040 | -- Continue with minor cycles and return for interaction |
2061 2041 | after the next major cycle. |
2062 2042 | |
2063 - | Iteration control : -- max cycleniter : Trigger for the next major cycle |
2043 + | Iteration control : -- max cycleniter : Trigger for the next major cycle. |
2064 2044 | |
2065 2045 | The display begins with |
2066 2046 | [ min( cycleniter, niter - itercount ) ] |
2067 2047 | and can be edited by hand. |
2068 2048 | |
2069 2049 | -- iterations left : The display begins with [niter-itercount ] |
2070 2050 | and can be edited to increase or |
2071 2051 | decrease the total allowed niter. |
2072 2052 | |
2073 - | -- threshold : Edit global stopping threshold |
2053 + | -- threshold : Edit global stopping threshold. |
2074 2054 | |
2075 2055 | -- cyclethreshold : The display begins with the |
2076 2056 | automatically computed value |
2077 2057 | (see Note in help for 'threshold'), |
2078 2058 | and can be edited by hand. |
2079 2059 | |
2080 2060 | All edits will be reflected in the log messages that appear |
2081 2061 | once minor cycles begin. |
2082 2062 | |
2083 2063 | </description> |
2117 2097 | of the residual, and no minor cycles are executed. |
2118 2098 | Case 2; nmajor=1, calcres=False: The major cycle is done as part of the |
2119 2099 | major/minor cycle loop, and 1 minor cycle will be executed. |
2120 2100 | </description> |
2121 2101 | <value type="int">-1</value> |
2122 2102 | </param> |
2123 2103 | |
2124 2104 | |
2125 2105 | <param type="bool" name="fullsummary"> |
2126 2106 | <shortdescription>Return dictionary with complete convergence history</shortdescription> |
2127 - | <description>Return dictionary with complete convergence history |
2107 + | <description>Return dictionary with complete convergence history. |
2128 2108 | |
2129 2109 | fullsummary=True: A full version of the summary dictionary is returned. |
2130 2110 | Keys include 'iterDone','peakRes','modelFlux','cycleThresh' that record the |
2131 2111 | convergence state at the end of each set of minor cycle iterations |
2132 2112 | separately for each image plane (i.e. channel/stokes) being |
2133 2113 | deconvolved. Additional keys report the convergence state at the |
2134 2114 | start of minor cycle iterations, stopping criteria that triggered major |
2135 2115 | cycles, and a processor ID per channel, for parallel cube runs. |
2136 2116 | |
2137 2117 | fullsummary=False (default): A shorten version of the summary dictionary is returned |
2150 2130 | </description> |
2151 2131 | <value type='bool'>False</value> |
2152 2132 | </param> |
2153 2133 | |
2154 2134 | |
2155 2135 | |
2156 2136 | |
2157 2137 | <param type="string" name="usemask"> |
2158 2138 | <shortdescription>Type of mask(s) for deconvolution: user, pb, or auto-multithresh</shortdescription> |
2159 2139 | |
2160 - | <description>Type of mask(s) to be used for deconvolution |
2140 + | <description>Type of mask(s) to be used for deconvolution. |
2161 2141 | |
2162 - | user: (default) mask image(s) or user specified region file(s) or string CRTF expression(s) |
2163 - | subparameters: mask, pbmask |
2164 - | pb: primary beam mask |
2165 - | subparameter: pbmask |
2142 + | user: (default) mask image(s) or user specified region file(s) or string CRTF expression(s). |
2143 + | subparameters: mask, pbmask. |
2144 + | pb: primary beam mask. |
2145 + | subparameter: pbmask. |
2166 2146 | |
2167 - | Example: usemask="pb", pbmask=0.2 |
2147 + | Example: usemask="pb", pbmask=0.2. |
2168 2148 | Construct a mask at the 0.2 pb gain level. |
2169 2149 | (Currently, this option will work only with |
2170 2150 | gridders that produce .pb (i.e. mosaic and awproject) |
2171 - | or if an externally produced .pb image exists on disk) |
2151 + | or if an externally produced .pb image exists on disk). |
2172 2152 | |
2173 - | auto-multithresh : auto-masking by multiple thresholds for deconvolution |
2153 + | auto-multithresh : auto-masking by multiple thresholds for deconvolution. |
2174 2154 | subparameters : sidelobethreshold, noisethreshold, lownoisethreshold, negativethrehsold, smoothfactor, |
2175 - | minbeamfrac, cutthreshold, pbmask, growiterations, dogrowprune, minpercentchange, verbose |
2176 - | Additional top level parameter relevant to auto-multithresh: fastnoise |
2155 + | minbeamfrac, cutthreshold, pbmask, growiterations, dogrowprune, minpercentchange, verbose. |
2156 + | Additional top level parameter relevant to auto-multithresh: fastnoise. |
2177 2157 | |
2178 2158 | if pbmask is >0.0, the region outside the specified pb gain level is excluded from |
2179 2159 | image statistics in determination of the threshold. |
2180 2160 | |
2181 2161 | |
2182 2162 | |
2183 2163 | |
2184 2164 | Note: By default the intermediate mask generated by automask at each deconvolution cycle |
2185 2165 | is over-written in the next cycle but one can save them by setting |
2186 2166 | the environment variable, SAVE_ALL_AUTOMASKS="true". |
2193 2173 | <allowed kind="enum"> |
2194 2174 | <value>user</value> |
2195 2175 | <value>pb</value> |
2196 2176 | <value>auto-multithresh</value> |
2197 2177 | </allowed> |
2198 2178 | </param> |
2199 2179 | |
2200 2180 | |
2201 2181 | <param type="any" name="mask" subparam="true"> |
2202 2182 | <shortdescription>Mask (a list of image name(s) or region file(s) or region string(s) )</shortdescription> |
2203 - | <description>Mask (a list of image name(s) or region file(s) or region string(s) |
2183 + | <description>Mask (a list of image name(s) or region file(s) or region string(s). |
2204 2184 | |
2205 2185 | |
2206 2186 | The name of a CASA image or region file or region string that specifies |
2207 2187 | a 1/0 mask to be used for deconvolution. Only locations with value 1 will |
2208 2188 | be considered for the centers of flux components in the minor cycle. |
2209 2189 | If regions specified fall completely outside of the image, tclean will throw an error. |
2210 2190 | |
2211 2191 | Manual mask options/examples : |
2212 2192 | |
2213 2193 | mask='xxx.mask' : Use this CASA image named xxx.mask and containing |
2227 2207 | parameter. ] |
2228 2208 | |
2229 2209 | |
2230 2210 | mask='xxx.crtf' : A text file with region strings and the following on the first line |
2231 2211 | ( #CRTFv0 CASA Region Text Format version 0 ) |
2232 2212 | This is the format of a file created via the viewer's region |
2233 2213 | tool when saved in CASA region file format. |
2234 2214 | |
2235 2215 | mask='circle[[40pix,40pix],10pix]' : A CASA region string. |
2236 2216 | |
2237 - | mask=['xxx.mask','xxx.crtf', 'circle[[40pix,40pix],10pix]'] : a list of masks |
2217 + | mask=['xxx.mask','xxx.crtf', 'circle[[40pix,40pix],10pix]'] : a list of masks. |
2238 2218 | |
2239 2219 | |
2240 2220 | |
2241 2221 | |
2242 2222 | |
2243 2223 | Note : Mask images for deconvolution must contain 1 or 0 in each pixel. |
2244 2224 | Such a mask is different from an internal T/F mask that can be |
2245 2225 | held within each CASA image. These two types of masks are not |
2246 2226 | automatically interchangeable, so please use the makemask task |
2247 2227 | to copy between them if you need to construct a 1/0 based mask |
2253 2233 | </description> |
2254 2234 | |
2255 2235 | |
2256 2236 | <type>string</type><type>stringVec</type> |
2257 2237 | <value type="string"/> |
2258 2238 | </param> |
2259 2239 | |
2260 2240 | |
2261 2241 | <param type="double" name="pbmask" subparam="true"> |
2262 2242 | <shortdescription>primary beam mask</shortdescription> |
2263 - | <description>Sub-parameter for usemask: primary beam mask |
2243 + | <description>Sub-parameter for usemask: primary beam mask. |
2264 2244 | |
2265 - | Examples : pbmask=0.0 (default, no pb mask) |
2266 - | pbmask=0.2 (construct a mask at the 0.2 pb gain level) |
2245 + | Examples : pbmask=0.0 (default, no pb mask). |
2246 + | pbmask=0.2 (construct a mask at the 0.2 pb gain level). |
2267 2247 | |
2268 2248 | </description> |
2269 2249 | <value type="double">0.0</value> |
2270 2250 | </param> |
2271 2251 | |
2272 2252 | |
2273 2253 | |
2274 2254 | |
2275 2255 | <param type="double" name="sidelobethreshold" subparam="true"> |
2276 2256 | <shortdescription>sidelobethreshold \* the max sidelobe level \* peak residual</shortdescription> |
2277 2257 | <value type="double">3.0</value> |
2278 - | <description>Sub-parameter for "auto-multithresh": mask threshold based on sidelobe levels: sidelobethreshold \* max_sidelobe_level \* peak residual |
2258 + | <description>Sub-parameter for "auto-multithresh": mask threshold based on sidelobe levels: sidelobethreshold \* max_sidelobe_level \* peak residual. |
2279 2259 | |
2280 2260 | </description> |
2281 2261 | </param> |
2282 2262 | <param type="double" name="noisethreshold" subparam="true"> |
2283 2263 | <shortdescription>noisethreshold \* rms in residual image + location(median) </shortdescription> |
2284 2264 | <value type="double">5.0</value> |
2285 - | <description>Sub-parameter for "auto-multithresh": mask threshold based on the noise level: noisethreshold \* rms + location (=median) |
2265 + | <description>Sub-parameter for "auto-multithresh": mask threshold based on the noise level: noisethreshold \* rms + location (=median). |
2286 2266 | |
2287 - | The rms is calculated from MAD with rms = 1.4826\*MAD. |
2267 + | The rms is calculated from the median absolute deviation (MAD), with rms = 1.4826\*MAD. |
2288 2268 | </description> |
2289 2269 | </param> |
2290 2270 | <param type="double" name="lownoisethreshold" subparam="true"> |
2291 2271 | <shortdescription>lownoisethreshold \* rms in residual image + location(median) </shortdescription> |
2292 2272 | <value type="double">1.5</value> |
2293 - | <description>Sub-parameter for "auto-multithresh": mask threshold to grow previously masked regions via binary dilation: lownoisethreshold \* rms in residual image + location (=median) |
2273 + | <description>Sub-parameter for "auto-multithresh": mask threshold to grow previously masked regions via binary dilation: lownoisethreshold \* rms in residual image + location (=median). |
2294 2274 | |
2295 - | The rms is calculated from MAD with rms = 1.4826\*MAD. |
2275 + | The rms is calculated from the median absolute deviation (MAD), with rms = 1.4826\*MAD. |
2296 2276 | </description> |
2297 2277 | </param> |
2298 2278 | <param type="double" name="negativethreshold" subparam="true"> |
2299 2279 | <shortdescription>negativethreshold \* rms in residual image + location(median) </shortdescription> |
2300 2280 | <value type="double">0.0</value> |
2301 - | <description>Sub-parameter for "auto-multithresh": mask threshold for negative features: -1.0* negativethreshold \* rms + location(=median) |
2281 + | <description>Sub-parameter for "auto-multithresh": mask threshold for negative features: -1.0* negativethreshold \* rms + location(=median). |
2302 2282 | |
2303 - | The rms is calculated from MAD with rms = 1.4826\*MAD. |
2283 + | The rms is calculated from the median absolute deviation (MAD), with rms = 1.4826\*MAD. |
2304 2284 | </description> |
2305 2285 | </param> |
2306 2286 | <param type="double" name="smoothfactor" subparam="true"> |
2307 2287 | <shortdescription>smoothing factor in a unit of the beam</shortdescription> |
2308 2288 | <value type="double">1.0</value> |
2309 - | <description>Sub-parameter for "auto-multithresh": smoothing factor in a unit of the beam |
2289 + | <description>Sub-parameter for "auto-multithresh": smoothing factor in a unit of the beam. |
2310 2290 | </description> |
2311 2291 | </param> |
2312 2292 | <param type="double" name="minbeamfrac" subparam="true"> |
2313 2293 | <shortdescription>minimum beam fraction for pruning</shortdescription> |
2314 2294 | <value type="double">0.3</value> |
2315 2295 | <description>Sub-parameter for "auto-multithresh": minimum beam fraction in size to prune masks smaller than mimbeamfrac \* beam |
2316 2296 | <=0.0 : No pruning |
2317 2297 | </description> |
2318 2298 | </param> |
2319 2299 | <param type="double" name="cutthreshold" subparam="true"> |
2320 2300 | <shortdescription>threshold to cut the smoothed mask to create a final mask</shortdescription> |
2321 2301 | <value type="double">0.01</value> |
2322 - | <description>Sub-parameter for "auto-multithresh": threshold to cut the smoothed mask to create a final mask: cutthreshold \* peak of the smoothed mask |
2302 + | <description>Sub-parameter for "auto-multithresh": threshold to cut the smoothed mask to create a final mask: cutthreshold \* peak of the smoothed mask. |
2323 2303 | </description> |
2324 2304 | </param> |
2325 2305 | <param type="int" name="growiterations" subparam="true"> |
2326 2306 | <shortdescription>number of binary dilation iterations for growing the mask</shortdescription> |
2327 2307 | <value type="int">75</value> |
2328 - | <description>Sub-parameter for "auto-multithresh": Maximum number of iterations to perform using binary dilation for growing the mask |
2308 + | <description>Sub-parameter for "auto-multithresh": Maximum number of iterations to perform using binary dilation for growing the mask. |
2329 2309 | </description> |
2330 2310 | </param> |
2331 2311 | |
2332 2312 | <param type="bool" name="dogrowprune" subparam="true"> |
2333 2313 | <shortdescription>Do pruning on the grow mask</shortdescription> |
2334 2314 | <value type="bool">True</value> |
2335 - | <description>Experimental sub-parameter for "auto-multithresh": Do pruning on the grow mask |
2315 + | <description>Experimental sub-parameter for "auto-multithresh": Do pruning on the grow mask. |
2336 2316 | </description> |
2337 2317 | </param> |
2338 2318 | |
2339 2319 | <param type="double" name="minpercentchange" subparam="true"> |
2340 2320 | <shortdescription>minimum percentage change in mask size (per channel plane) to trigger updating of mask by automask </shortdescription> |
2341 2321 | <value type="double">-1.0</value> |
2342 2322 | <description>If the change in the mask size in a particular channel is less than minpercentchange, stop masking that channel in subsequent cycles. This check is only applied when noise based threshold is used and when the previous clean major cycle had a cyclethreshold value equal to the clean threshold. Values equal to -1.0 (or any value less than 0.0) will turn off this check (the default). Automask will still stop masking if the current channel mask is an empty mask and the noise threshold was used to determine the mask. |
2343 2323 | </description> |
2344 2324 | </param> |
2345 2325 | |
2346 2326 | <param type="bool" name="verbose" subparam="true"> |
2347 2327 | <shortdescription>True: print more automasking information in the logger</shortdescription> |
2348 2328 | <value type="bool">False</value> |
2349 2329 | <description> If it is set to True, the summary of automasking at the end of each automasking process |
2350 2330 | is printed in the logger. Following information per channel will be listed in the summary. |
2351 2331 | |
2352 - | chan: channel number |
2353 - | masking?: F - stop updating automask for the subsequent iteration cycles |
2354 - | RMS: robust rms noise |
2355 - | peak: peak in residual image |
2356 - | thresh_type: type of threshold used (noise or sidelobe) |
2357 - | thresh_value: the value of threshold used |
2358 - | N_reg: number of the automask regions |
2359 - | N_pruned: number of the automask regions removed by pruning |
2360 - | N_grow: number of the grow mask regions |
2361 - | N_grow_pruned: number of the grow mask regions removed by pruning |
2362 - | N_neg_pix: number of pixels for negative mask regions |
2363 - | |
2332 + | chan: channel number. |
2333 + | masking?: F - stop updating automask for the subsequent iteration cycles. |
2334 + | RMS: robust rms noise. |
2335 + | peak: peak in residual image. |
2336 + | thresh_type: type of threshold used (noise or sidelobe). |
2337 + | thresh_value: the value of threshold used. |
2338 + | N_reg: number of the automask regions. |
2339 + | N_pruned: number of the automask regions removed by pruning. |
2340 + | N_grow: number of the grow mask regions. |
2341 + | N_grow_pruned: number of the grow mask regions removed by pruning. |
2342 + | N_neg_pix: number of pixels for negative mask regions. |
2343 + | |
2364 2344 | Note that for a large cube, extra logging may slow down the process. |
2365 2345 | </description> |
2366 2346 | </param> |
2367 2347 | <param type="bool" name="fastnoise"> |
2368 2348 | <shortdescription>True: use the faster (old) noise calculation. False: use the new improved noise calculations</shortdescription> |
2369 2349 | <value type="bool">True</value> |
2370 2350 | <description> Only relevant when automask (user='multi-autothresh') and/or n-sigma stopping threshold (nsigma>0.0) are/is used. If it is set to True, a simpler but faster noise calucation is used. |
2371 2351 | In this case, the threshold values are determined based on classic statistics (using all |
2372 2352 | unmasked pixels for the calculations). |
2373 2353 | |
2374 2354 | If it is set to False, the new noise calculation |
2375 2355 | method is used based on pre-existing mask. |
2376 2356 | |
2377 - | Case 1: no exiting mask |
2378 - | Calculate image statistics using Chauvenet algorithm |
2357 + | Case 1: no exiting mask. |
2358 + | Calculate image statistics using Chauvenet algorithm. |
2379 2359 | |
2380 - | Case 2: there is an existing mask |
2360 + | Case 2: there is an existing mask. |
2381 2361 | Calculate image statistics by classical method on the region |
2382 2362 | outside the mask and inside the primary beam mask. |
2383 2363 | |
2384 - | In all cases above RMS noise is calculated from MAD. |
2364 + | In all cases above RMS noise is calculated from the median absolute deviation (MAD). |
2385 2365 | </description> |
2386 2366 | </param> |
2387 2367 | |
2388 2368 | |
2389 2369 | |
2390 2370 | |
2391 2371 | <param type="bool" name="restart"> |
2392 2372 | <shortdescription>True : Re-use existing images. False : Increment imagename</shortdescription> |
2393 2373 | <description> Restart using existing images (and start from an existing model image) |
2394 2374 | or automatically increment the image name and make a new image set. |
2395 2375 | |
2396 2376 | True : Re-use existing images. If imagename.model exists the subsequent |
2397 2377 | run will start from this model (i.e. predicting it using current gridder |
2398 2378 | settings and starting from the residual image). Care must be taken |
2399 2379 | when combining this option with startmodel. Currently, only one or |
2400 2380 | the other can be used. |
2401 2381 | |
2402 2382 | startmodel='', imagename.model exists : |
2403 - | - Start from imagename.model |
2383 + | - Start from imagename.model. |
2404 2384 | startmodel='xxx', imagename.model does not exist : |
2405 - | - Start from startmodel |
2385 + | - Start from startmodel. |
2406 2386 | startmodel='xxx', imagename.model exists : |
2407 2387 | - Exit with an error message requesting the user to pick |
2408 2388 | only one model. This situation can arise when doing one |
2409 2389 | run with startmodel='xxx' to produce an output |
2410 2390 | imagename.model that includes the content of startmodel, |
2411 2391 | and wanting to restart a second run to continue deconvolution. |
2412 2392 | Startmodel should be set to '' before continuing. |
2413 2393 | |
2414 2394 | If any change in the shape or coordinate system of the image is |
2415 2395 | desired during the restart, please change the image name and |
2439 2419 | 'outry' and 'outtry_2' have not been used. |
2440 2420 | |
2441 2421 | |
2442 2422 | </description> |
2443 2423 | <value type="bool">True</value> |
2444 2424 | </param> |
2445 2425 | |
2446 2426 | |
2447 2427 | <param type="string" name="savemodel"> |
2448 2428 | <shortdescription>Options to save model visibilities (none, virtual, modelcolumn)</shortdescription> |
2449 - | <description>Options to save model visibilities (none, virtual, modelcolumn) |
2429 + | <description>Options to save model visibilities (none, virtual, modelcolumn). |
2450 2430 | |
2451 2431 | Often, model visibilities must be created and saved in the MS |
2452 2432 | to be later used for self-calibration (or to just plot and view them). |
2453 2433 | |
2454 2434 | none : Do not save any model visibilities in the MS. The MS is opened |
2455 2435 | in readonly mode. |
2456 2436 | |
2457 2437 | Model visibilities can be predicted in a separate step by |
2458 2438 | restarting tclean with niter=0,savemodel=virtual or modelcolumn |
2459 2439 | and not changing any image names so that it finds the .model on |
2499 2479 | <value>virtual</value> |
2500 2480 | <value>modelcolumn</value> |
2501 2481 | </allowed> |
2502 2482 | </param> |
2503 2483 | |
2504 2484 | |
2505 2485 | |
2506 2486 | |
2507 2487 | <param type="bool" name="calcres"> |
2508 2488 | <shortdescription>Calculate initial residual image</shortdescription> |
2509 - | <description>Calculate initial residual image |
2489 + | <description>Calculate initial residual image. |
2510 2490 | |
2511 2491 | This parameter controls what the first major cycle does. |
2512 2492 | |
2513 2493 | calcres=False with niter greater than 0 will assume that |
2514 2494 | a .residual image already exists and that the minor cycle can |
2515 2495 | begin without recomputing it. |
2516 2496 | |
2517 2497 | calcres=False with niter=0 implies that only the PSF will be made |
2518 2498 | and no data will be gridded. |
2519 2499 | |
2570 2550 | </description> |
2571 2551 | <value type="double">0.35</value> |
2572 2552 | |
2573 2553 | </param> |
2574 2554 | |
2575 2555 | |
2576 2556 | |
2577 2557 | |
2578 2558 | <param type="bool" name="parallel"> |
2579 2559 | <shortdescription>Run major cycles in parallel</shortdescription> |
2580 - | <description>Run major cycles in parallel (this feature is experimental) |
2560 + | <description>Run major cycles in parallel. |
2581 2561 | |
2582 2562 | Parallel tclean will run only if casa has already been started using mpirun. |
2583 - | Please refer to HPC documentation for details on how to start this on your system. |
2563 + | Please refer to external resources on high performance computing for details on how to start this on your system. |
2584 2564 | |
2585 2565 | Example : mpirun -n 3 -xterm 0 `which casa` |
2586 2566 | |
2587 2567 | Continuum Imaging : |
2588 - | - Data are partitioned (in time) into NProc pieces |
2589 - | - Gridding/iFT is done separately per partition |
2590 - | - Images (and weights) are gathered and then normalized |
2591 - | - One non-parallel minor cycle is run |
2592 - | - Model image is scattered to all processes |
2593 - | - Major cycle is done in parallel per partition |
2568 + | - Data are partitioned (in time) into NProc pieces. |
2569 + | - Gridding/iFT is done separately per partition. |
2570 + | - Images (and weights) are gathered and then normalized. |
2571 + | - One non-parallel minor cycle is run. |
2572 + | - Model image is scattered to all processes. |
2573 + | - Major cycle is done in parallel per partition. |
2594 2574 | |
2595 2575 | Cube Imaging : |
2596 - | - Data and Image coordinates are partitioned (in freq) into NProc pieces |
2597 - | - Each partition is processed independently (major and minor cycles) |
2598 - | - All processes are synchronized at major cycle boundaries for convergence checks |
2599 - | - At the end, cubes from all partitions are concatenated along the spectral axis |
2576 + | - Data and Image coordinates are partitioned (in freq) into NProc pieces. |
2577 + | - Each partition is processed independently (major and minor cycles). |
2578 + | - All processes are synchronized at major cycle boundaries for convergence checks. |
2579 + | - At the end, cubes from all partitions are concatenated along the spectral axis. |
2600 2580 | |
2601 2581 | Note 1 : Iteration control for cube imaging is independent per partition. |
2602 2582 | - There is currently no communication between them to synchronize |
2603 2583 | information such as peak residual and cyclethreshold. Therefore, |
2604 2584 | different chunks may trigger major cycles at different levels. |
2605 2585 | (Proper synchronization of iteration control is work in progress.) |
2606 2586 | |
2607 2587 | </description> |
2608 2588 | <value type="bool">False</value> |
2609 2589 | </param> |
2888 2868 | |
2889 2869 | |
2890 2870 | </constraints> |
2891 2871 | |
2892 2872 | </input> |
2893 2873 | |
2894 2874 | <returns type="void"/> |
2895 2875 | |
2896 2876 | <example> |
2897 2877 | |
2898 - | Please refer to the CASAdocs pages for the task tclean for examples. |
2878 + | For more information, see the task pages of tclean in CASA Docs: |
2879 + | |
2880 + | https://casadocs.readthedocs.io |
2881 + | |
2899 2882 | |
2900 2883 | </example> |
2901 2884 | |
2902 2885 | </task> |
2903 2886 | |
2904 2887 | </casaxml> |