Recent changes to Usage

Usage modified by André Offringa

André Offringa — Fri, 31 Jan 2020 13:53:50 -0000

--- v22
+++ v23
@@ -40,3 +40,5 @@
 * A larger `mgain` value is used because the MWA synthesized beam is well behaved.
 * A larger image is made because GLEAM includes lower frequencies, at which the primary beam is larger.
 * For GLEAM, the W-snapshot algorithm is used by executing the `chgcentre` command prior to imaging, as described on the [W-snapshot page](WSnapshotAlgorithm).
+
+**Next chapter: [basic cleaning](BasicCleaning)**

Usage modified by André Offringa

André Offringa — Fri, 01 Dec 2017 11:16:02 -0000

--- v21
+++ v22
@@ -30,7 +30,7 @@

     :::bash
     wsclean -name ${obsname} -size 4000 4000 -niter 40000 -threshold 0.3 -pol xx,yy \
-      -weight briggs -1.0 -scale 0.0125 -absmem 128 -joinpolarizations \
+      -weight briggs -1.0 -scale 0.0125 -absmem 128 -join-polarizations \
       -j 12 -mgain 0.95 1068210256.ms

 A little explanation of this command:

Usage modified by André Offringa

André Offringa — Fri, 01 Dec 2017 11:15:19 -0000

--- v20
+++ v21
@@ -17,7 +17,7 @@
 For fast imaging with somewhat less accuracy, you can perform a Högbom clean and disable padding:

     :::bash
-    # Same, but now only Högbom cleaning
+    # Similar to above statement, but now only Högbom cleaning and no padding
     wsclean -size 3072 3072 -scale 0.7amin -niter 10000 \
       -auto-threshold 3 -padding 1 obs.ms

Usage modified by André Offringa

André Offringa — Fri, 01 Dec 2017 11:13:08 -0000

--- v19
+++ v20
@@ -14,11 +14,12 @@

 This performs a Cotton-Schwab clean. The Cotton-Schwab algorithm is enabled with the "`-mgain 0.8`" parameter, which means that the peak flux is reduced by 80% until a new major iteration is started. Multiple measurement sets can be specified on the command line to image the integration of those observations.

-For fast imaging with somewhat less accuracy, you can perform a Högbom clean:
+For fast imaging with somewhat less accuracy, you can perform a Högbom clean and disable padding:

     :::bash
     # Same, but now only Högbom cleaning
-    wsclean -size 3072 3072 -scale 0.7amin -niter 10000 -auto-threshold 3 obs.ms
+    wsclean -size 3072 3072 -scale 0.7amin -niter 10000 \
+      -auto-threshold 3 -padding 1 obs.ms

 Because the '`mgain`' parameter was left out, WSClean will not iteratively go back to the visibilities. This also implies that the MODEL_DATA column will not be filled (see [self-calibration with WSClean](WSCleanAndSelfcal) for more info).

Usage modified by André Offringa

André Offringa — Sat, 21 Jan 2017 09:58:44 -0000

--- v18
+++ v19
@@ -8,7 +8,7 @@

     :::bash
     # Make a Stokes I image of size 3072x3072 with 0.7' pixels, do 10000 iterations,
-    # use CS cleaning and stop at 1 Jy.
+    # use CS cleaning and stop when the peak flux has reached 3σ level.
     wsclean -size 3072 3072 -scale 0.7amin -niter 10000 \
       -mgain 0.8 -auto-threshold 3 obs.ms

Usage modified by André Offringa

André Offringa — Sat, 21 Jan 2017 09:57:40 -0000

--- v17
+++ v18
@@ -10,7 +10,7 @@
     # Make a Stokes I image of size 3072x3072 with 0.7' pixels, do 10000 iterations,
     # use CS cleaning and stop at 1 Jy.
     wsclean -size 3072 3072 -scale 0.7amin -niter 10000 \
-      -mgain 0.8 -threshold 0.2 obs.ms
+      -mgain 0.8 -auto-threshold 3 obs.ms

 This performs a Cotton-Schwab clean. The Cotton-Schwab algorithm is enabled with the "`-mgain 0.8`" parameter, which means that the peak flux is reduced by 80% until a new major iteration is started. Multiple measurement sets can be specified on the command line to image the integration of those observations.

@@ -18,7 +18,7 @@

     :::bash
     # Same, but now only Högbom cleaning
-    wsclean -size 3072 3072 -scale 0.7amin -niter 10000 -threshold 0.2 obs.ms
+    wsclean -size 3072 3072 -scale 0.7amin -niter 10000 -auto-threshold 3 obs.ms

 Because the '`mgain`' parameter was left out, WSClean will not iteratively go back to the visibilities. This also implies that the MODEL_DATA column will not be filled (see [self-calibration with WSClean](WSCleanAndSelfcal) for more info).

Usage modified by André Offringa

André Offringa — Fri, 04 Nov 2016 07:40:47 -0000

--- v16
+++ v17
@@ -1,5 +1,5 @@
 ## General usage of WSClean
-WSClean is a command line program. The "`wsclean`" executable accepts many parameters. The "`wsclean`" program can be run without parameters to get a list of them. The general syntax of wsclean is as follows:
+WSClean is a command line program. The "`wsclean`" executable accepts many parameters. The "`wsclean`" program can be run without parameters to get a list of allowed parameters together with a short description. The general syntax of wsclean is as follows:

     :::bash
     wsclean [-options] <obs1.ms> [<obs2.ms> ..]
@@ -12,7 +12,7 @@
     wsclean -size 3072 3072 -scale 0.7amin -niter 10000 \
       -mgain 0.8 -threshold 0.2 obs.ms

-This performs a Cotton-Schwab clean. The Cotton-Schwab algorithm is enabled with the "-mgain 0.8" parameter, which means that the peak flux is reduced by 80% until a new major iteration is started. Multiple measurement sets can be specified on the command line to image the integration of those observations.
+This performs a Cotton-Schwab clean. The Cotton-Schwab algorithm is enabled with the "`-mgain 0.8`" parameter, which means that the peak flux is reduced by 80% until a new major iteration is started. Multiple measurement sets can be specified on the command line to image the integration of those observations.

 For fast imaging with somewhat less accuracy, you can perform a Högbom clean:

@@ -22,8 +22,10 @@

 Because the '`mgain`' parameter was left out, WSClean will not iteratively go back to the visibilities. This also implies that the MODEL_DATA column will not be filled (see [self-calibration with WSClean](WSCleanAndSelfcal) for more info).

+A description of the basic cleaning parameters is given on the [manual page for basic cleaning](BasicCleaning).
+
 ####An advanced MWA example
-As a more enhanced example, Natasha Hurley-Walker is currently (June 2014) imaging GLEAM data with the following command:
+As a more enhanced example, Natasha Hurley-Walker has been imaging GLEAM data with the following command:

     :::bash
     wsclean -name ${obsname} -size 4000 4000 -niter 40000 -threshold 0.3 -pol xx,yy \

Usage modified by André Offringa

André Offringa — Tue, 29 Mar 2016 07:26:50 -0000

--- v15
+++ v16
@@ -1,16 +1,16 @@
 ## General usage of WSClean
-The "wsclean" program can be run without parameters to get a list of allowed parameters. The syntax of wsclean is as follows:
+WSClean is a command line program. The "`wsclean`" executable accepts many parameters. The "`wsclean`" program can be run without parameters to get a list of them. The general syntax of wsclean is as follows:

     :::bash
     wsclean [-options] <obs1.ms> [<obs2.ms> ..]

-A typical "accurate" MWA run looks like this:
+Here's an example of a typical MWA run:

     :::bash
     # Make a Stokes I image of size 3072x3072 with 0.7' pixels, do 10000 iterations,
     # use CS cleaning and stop at 1 Jy.
     wsclean -size 3072 3072 -scale 0.7amin -niter 10000 \
-      -mgain 0.8 -threshold 1 obs.ms
+      -mgain 0.8 -threshold 0.2 obs.ms

 This performs a Cotton-Schwab clean. The Cotton-Schwab algorithm is enabled with the "-mgain 0.8" parameter, which means that the peak flux is reduced by 80% until a new major iteration is started. Multiple measurement sets can be specified on the command line to image the integration of those observations.

@@ -18,10 +18,11 @@

     :::bash
     # Same, but now only Högbom cleaning
-    wsclean -size 3072 3072 -scale 0.7amin -niter 10000 -threshold 1 obs.ms
+    wsclean -size 3072 3072 -scale 0.7amin -niter 10000 -threshold 0.2 obs.ms

-Because of leaving out 'mgain', WSClean will not go back to the visibilities. This also implies that the MODEL_DATA column will not be filled (see [self-calibration with WSClean](WSCleanAndSelfcal) for more info).
+Because the '`mgain`' parameter was left out, WSClean will not iteratively go back to the visibilities. This also implies that the MODEL_DATA column will not be filled (see [self-calibration with WSClean](WSCleanAndSelfcal) for more info).

+####An advanced MWA example
 As a more enhanced example, Natasha Hurley-Walker is currently (June 2014) imaging GLEAM data with the following command:

     :::bash
@@ -31,8 +32,8 @@

 A little explanation of this command:

-* The (instrumental) XX and YY polarizations are imaged separately and cleaned together. This allows more accurate primary beam correction for the MWA.
-* Briggs' weighting with robustness of -1 is used. For the MWA, this decreases the noise in single snapshots slightly.
-* A larger mgain value is used because the MWA synthesized beam is well behaved.
+* Briggs' weighting with robustness of -1 is used. For the MWA, this decreases the noise in single snapshots slightly. See [image weighting](ImageWeighting) for more info on supported weightings.
+* The (instrumental) XX and YY polarizations are imaged separately and cleaned together. This allows more accurate primary beam correction for the MWA. See [polarized cleaning](PolarizedCleaning) for more info.
+* A larger `mgain` value is used because the MWA synthesized beam is well behaved.
 * A larger image is made because GLEAM includes lower frequencies, at which the primary beam is larger.
-* For GLEAM, the W-snapshot algorithm is used by executing the chgcentre command prior to imaging, as described on the [W-snapshot page](WSnapshotAlgorithm).
+* For GLEAM, the W-snapshot algorithm is used by executing the `chgcentre` command prior to imaging, as described on the [W-snapshot page](WSnapshotAlgorithm).

Usage modified by André Offringa

André Offringa — Mon, 28 Mar 2016 15:12:18 -0000

--- v14
+++ v15
@@ -1,3 +1,4 @@
+## General usage of WSClean
 The "wsclean" program can be run without parameters to get a list of allowed parameters. The syntax of wsclean is as follows:

     :::bash

Usage modified by André Offringa

André Offringa — Mon, 24 Aug 2015 08:07:37 -0000

--- v13
+++ v14
@@ -19,7 +19,7 @@
     # Same, but now only Högbom cleaning
     wsclean -size 3072 3072 -scale 0.7amin -niter 10000 -threshold 1 obs.ms

-Because of leaving out 'mgain', this will not go back to the visibilities. This also implies that the MODEL_DATA column will not be filled (see [self-calibration with WSClean](WSCleanAndSelfcal) for more info).
+Because of leaving out 'mgain', WSClean will not go back to the visibilities. This also implies that the MODEL_DATA column will not be filled (see [self-calibration with WSClean](WSCleanAndSelfcal) for more info).

 As a more enhanced example, Natasha Hurley-Walker is currently (June 2014) imaging GLEAM data with the following command: