Changes between Version 18 and Version 19 of Notes/ExampleReduction

Timestamp:

03/31/09 12:42:29 (15 years ago)

Author:

JamieStevens

Comment:

--

Notes/ExampleReduction

@@ -190 +190 @@
 band only.
 
-Now we are ready to image the source. 
+Now we are ready to image the source. In the DAC method, there are three ways to make images of the source
+without recombining the UV data first. We will attempt all three methods:
+1. invert using the MFS option as normal, then clean and restor
+1. invert using both the MFS option and the SDB option, then use mfsclean and restor
+1. invert making a cube of all channels, then clean, restor and then make a moment map
+
+The first way is the way most familiar to MIRIAD users doing continuum reduction. We can make images of all
+the individual datasets in the following way:
+
+dac_repeat.pl --task invert --repeat vis --repeat-freq rnovalmc --repeat map --repeat-freq rnovalmc_%f.map --repeat beam --repeat-freq rnovalmc_%f.beam "select=-auto,-ant(6)" stokes=ii options=double,mfs slop=1
+
+This makes 16 each of the .map and .beam files. Let's get an idea of the RMS noise of each of the maps using
+imstat. Using kvis we can identify a region (xmin,ymin,xmax,ymax)=(39,0,65,22) that contains no emission.
+Using dac_repeat.pl we can run imstat on each set:
+
+./dac_repeat.pl --task imstat --repeat in --repeat-freq rnovalmc_%f.map "region=boxes(39,0,65,22)" axes=ra,dec
+
+From this we find that the RMS noise values are:
+|| f (MHz) || RMS (uJy) ||
+|| 4540    || 246       ||
+|| 4668    || 214       ||
+|| 4796    || 294       ||
+|| 4924    || 385       ||
+|| 5052    || 340       ||
+|| 5180    || 426       ||
+|| 5308    || 351       ||
+|| 5436    || 343       ||
+|| 5564    || 561       ||
+|| 5692    || 386       ||
+|| 5820    || 355       ||
+|| 5948    || 336       ||
+|| 6076    || 444       ||
+|| 6204    || 340       ||
+|| 6332    || 203       ||
+|| 6460    || 179       ||
+
+This gives us an average RMS of 338 uJy. We can use this value when cleaning:
+
+./dac_repeat.pl --task clean --repeat map --repeat-freq rnovalmc_%f.map --repeat beam --repeat-freq rnovalmc_%f.beam --repeat out --repeat-freq rnovalmc_%f.clean cutoff=0.001014
+
+And restor:
+
+./dac_repeat.pl --task restor --repeat model --repeat-freq rnovalmc_%f.clean --repeat beam --repeat-freq rnovalmc_%f.beam --repeat map --repeat-freq rnovalmc_%f.map --repeat out --repeat-freq rnovalmc_%f.restor
+