Changes between Version 1 and Version 2 of Notes/FirstNightReduction

Timestamp:

04/02/09 15:48:56 (15 years ago)

Author:

JamieStevens

Comment:

--

Notes/FirstNightReduction

@@ -17 +17 @@
 The files we are using are:
 {{{
-4.5G 2009-04-02 11:14 2009-04-01_1407.C999
-4.7G 2009-04-02 11:15 2009-04-01_1543.C999
-2.8G 2009-04-02 11:17 2009-04-01_1723.C999
-1.9G 2009-04-02 11:17 2009-04-01_1822.C999
-3.1G 2009-04-02 11:18 2009-04-01_1938.C999
+4.5G  2009-04-01_1407.C999
+4.7G  2009-04-01_1543.C999
+2.8G  2009-04-01_1723.C999
+1.9G  2009-04-01_1822.C999
+3.1G  2009-04-01_1938.C999
 }}}
 for a total of 17G.
@@ -31 +31 @@
   in       = *.C999
   out      = firstnight_1934.uv
-  ifsel    = 1,2
+  ifsel    =  
   restfreq =  
-  options  =  
+  options  = noif
   nfiles   =  
   nscans   =  
 }}}
 
+We use options=noif since there are actually 4 IFs in each CABB file: IFs 1 & 2 are the 2 GHz 2048 channel
+wide-bands, while IFs 3 and 4 are the 4096 channel areas that the zoom bands will use. Since the IFs have
+different numbers of channels, ATLOD will fail if you ask it to map the IFs to the same channel axis. After
+using options=noif you may select the different IFs using the select=window options.
+
+Let's look at the data using uvplt (this takes quite a while with all the data!):
+{{{
+uvplt% inp
+  Task:   uvplt
+  vis      = firstnight_1934.uv/
+  line     =  
+  select   = -auto,window(1),pol(xx,yy)
+  stokes   =  
+  axis     = time,amp
+  xrange   =  
+  yrange   =  
+  average  =  
+  hann     =  
+  inc      =  
+  options  = nobase
+  subtitle =  
+  device   = firstnight_firstlook.png/png
+  nxy      =  
+  size     =  
+  log      =  
+  comment  =  
+}}}
+
+[[Image(firstnight_firstlook.png)]]
+
+This image shows us that something weird happened - we didn't observe on April 2! A quick
+uvindex shows the problem:
+{{{
+uvindex% inp
+  Task:   uvindex
+  vis      = firstnight_1934.uv/
+  interval =  
+  log      =  
+  options  =  
+}}}
+{{{
+09APR01:16:58:33.2 aa1              n  6      2049        0      1  318505
+09APR01:16:59:34.0 aa2              n  6      2049        0      1  321097
+09APR01:17:00:34.0 aa3              n  6      2049        0      1  323689
+09APR02:17:01:27.4 aa3              n  6      2049        0      1  326009
+09APR02:17:02:03.2 bb1              n  6      2049        0      1  326225
+09APR02:17:03:04.0 bb2              n  6      2049        0      1  328817
+09APR02:17:04:04.0 bb3              n  6      2049        0      1  331409
+09APR01:17:05:38.2 cc1              n  6      2049        0      1  334001
+09APR01:17:06:39.0 cc2              n  6      2049        0      1  336593
+09APR01:17:07:39.0 cc3              n  6      2049        0      1  339185
+}}}
+
+A little quirk has meant that the timestamp is wrong for a few scans. Since the quirk may have
+also corrupted the data, we take no chances and flag it out with uvflag:
+{{{
+uvflag% inp
+  Task:   uvflag
+  vis      = firstnight_1934.uv/
+  select   = time(09APR02:00:00:00)
+  line     =  
+  edge     =  
+  flagval  = flag
+  options  =  
+  log      =  
+}}}
+
+And looking at the data again shows us the following plot.
+
+[[Image(firstnight_aftertimeflag.png)]]
+
+So we can see that we are observing different sources and that the data looks as one would
+expect it to. Now let's just look at 1934-638, as we will use it as our primary calibrator.
+{{{
+uvplt% inp
+  Task:   uvplt
+  vis      = firstnight_1934.uv/
+  line     =  
+  select   = -auto,window(1),pol(xx,yy),source(aa1)
+  stokes   =  
+  axis     = time,amp
+  xrange   =  
+  yrange   =  
+  average  =  
+  hann     =  
+  inc      =  
+  options  = nobase
+  subtitle =  
+  device   = 1/xs
+  nxy      =  
+  size     =  
+  log      =  
+  comment  =  
+}}}
+Here we use the source name aa1 for the mosaic pointing on 1934-638 with no offset.
+
+[[Image(firstnight_1934_beforecal.png)]]
+
+And we can plot phase too:
+
+[[Image(firstnight_1934p_beforecal.png)]]
+
+And the bandpass:
+{{{
+uvspec% inp
+  Task:   uvspec
+  vis      = firstnight_1934.uv/
+  select   = -auto,window(1),pol(xx,yy),source(aa1)
+  line     =  
+  stokes   =  
+  interval = 10
+  hann     =  
+  offset   =  
+  options  = nobase,avall
+  axis     = freq,amp
+  yrange   =  
+  device   = firstnight_1934b_beforecal.png/png
+  nxy      = 3,4
+  log      =  
+}}}
+
+[[Image(firstnight_1934b_beforecal.png)]]
+
+Now we calibrate:
+{{{
+mfcal% inp
+  Task:   mfcal
+  vis      = firstnight_1934.uv/
+  line     =  
+  stokes   =  
+  edge     =  
+  select   = window(1),source(aa1)
+  flux     =  
+  refant   =  
+  minants  =  
+  interval = 0.1
+  options  =  
+  tol      =  
+}}}
+