Custom Query (104 matches)

Jess Broderick reports:

Imaging equatorial sources by Jess Broderick on Wed Apr 28, 2010 11:25 am

Hi,

I'm trying to make an image of a source at Dec -00:20:45. The data were obtained with the H168 configuration on March 23/24 at 5.5 and 9 GHz (project CX188). I have no problems with the calibration, but the dirty map produced with INVERT doesn't look quite right. First of all, the cell size changes across the image (at least according to KVIS); this happens if I let INVERT choose the default pixel size or I specify it myself. Secondly, there are some sources in the field whose positions I know from NVSS; they appear to have been shifted in my higher-frequency images.

Any suggestions? Even with the spur, is it possible to get a good image so close to the celestial equator?

Thanks, Jess Jess Broderick

blflag is unable to display recent CABB data, it dies while reading the data in.

To reproduce:

atlod in=2010-05-13_1001.C1825 out=test2 options=birdie,rfiflag,xycorr ifsel=1
...some warnings but works ok...
blflag vis=test2 options=nobase select="source(1253-055)" axis=time,amplitude device=/xs
BlFlag: version 23-Apr-09
Reading the data ...
### Fatal Error:  Variable systemp was not initialised before it was required, in UVREAD

The error message comes from uvio.c, uv_checkvar(), which is being called from uvinfo_variance(). uvinfo_variance is called by uvinfo_c(), which is called by blflag.for's flagchk() routine.

stracing shows the error occurs while reading the flag table:

strace -f -s2048 -o t.blflag blflag vis=test2 options=nobase select="source(1253-055)" axis=time,amplitude device=/xs

Looking at the end of the trace file, we see

27090 open("test2/flags", O_RDONLY)     = 5
27090 lseek(5, 0, SEEK_END)             = 3003444
27090 lseek(5, 0, SEEK_SET)             = 0
27090 read(5, "\0\0\0\2\0\0\0\0\0\0\0\0\0\0\0\0\177\377\377\200\177\377\377
...
374\374y\371\371\371\177"..., 16384) = 16384
27090 write(2, "### Fatal Error:  Variable systemp was not initialised before it was required, in UVREAD\n", 89) = 89
27090 close(5)                          = 0
27090 close(3)                          = 0
27090 lseek(2, 0, SEEK_CUR)             = -1 ESPIPE (Illegal seek)
27090 fstat(2, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
27090 lseek(2, 0, SEEK_END)             = -1 ESPIPE (Illegal seek)
27090 lseek(2, 0, SEEK_CUR)             = -1 ESPIPE (Illegal seek)
27090 lseek(1, 0, SEEK_CUR)             = -1 ESPIPE (Illegal seek)
27090 fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
27090 lseek(1, 0, SEEK_END)             = -1 ESPIPE (Illegal seek)
27090 lseek(1, 0, SEEK_CUR)             = -1 ESPIPE (Illegal seek)
27090 munmap(0x2b9b6fc57000, 4096)      = 0
27090 exit_group(1)                     = ?

Other tasks are able to look at the uv data, e.g. uvplt:

uvplt vis=test2 device=/xs axis=uu,vv stokes=xx options=nobase
uvplt: Revision 1.10, 2010/04/30 08:23:28 UTC

 -1.00000003E+32  1.00000003E+32 -1.00000003E+32  1.00000003E+32
Will plot unflagged data



File # 1  = test2
test2 87.2750 GHz
Read 2840 visibilities from all files

Plot 2840 points

atlod produces logs of warnings about 'Corrupted data encountered' when loading RPFITS files with zoom-mode data in them.

To reproduce:

atlod in=2010-05-13_1001.C1825 out=test2 options=birdie,rfiflag,xyccorr ifsel=1

atlod: Revision 1.25, 2010/04/30 08:10:47 UTC

Flagging channels in  22 frequency ranges
Processing file 2010-05-13_1001.C1825
CABB data detected
  RPFITSIN: Corrupted data encountered, skipping...
  RPFITSIN: Corrupted data encountered, skipping...
  RPFITSIN: Corrupted data encountered, skipping...
  RPFITSIN: Corrupted data encountered, skipping...
...

This occurs with both the mainline version of atlod and the -cabb version. It is possible this is causing downstream problems, with other miriad tasks.