[daip] Problem loading FITS file in 31DEC06 version of AIPS

[Patrick P Murphy]

On Thu, 17 Aug 2006 00:32:13 +0200, Wouter van Reeven
   <wouter at van.reeven.nl> said: 

> A few years ago I used AIPS for my graduation paper on high redshift
> galaxies.  Having left professional astronomy, I am still an avid
> amateur astronomer. As of lately I am trying to create contour plots
> of some celestial objects using the AIPS software.  In order to get
> FITS images of these objects I am using some C++ code called get_dss,
> see

> http://www.projectpluto.com/get_dss.htm

> to get the FITS images off the RealSky CD set. This works fine, even
> with the source compiled on Debian Linux. The FITS images are shown
> perfectly ok in the GUIDE software the get_dss code was written
> for. Also, when I try to open the FITS images with The Gimp or
> Photoshop, they display correctly.  Unfortunately I haven't been able
> to load the images in AIPS. To this email I have attached a small
> sample of a FITS image.

That image has one defect: its size is not a multiple of 2880 bytes.  It
needs padded out like this:

 ( cat 0251.FIT ; dd if=/dev/zero bs=622 count=1 ) >0251-2.FIT

This will create a file that AIPS can read in:

samhai> FITLD1: Task FITLD  (release of 31DEC06) begins
samhai> FITLD1: Create FITLD       .TEMP  .   1 (MA)  on disk  1  cno    9
samhai> FITLD1: RENAM NONE        .IMAP  .   1 (MA)  ON DISK 1 CNO    9
samhai> FITLD1: Image=NONE      (MA)         Filename=NONE        .IMAP  .   1
samhai> FITLD1: Telescope=Palomar            Receiver=
samhai> FITLD1: Observer=                    User #=  370
samhai> FITLD1: Observ. date=12-MAY-1955     Map date=19-SEP-2006
samhai> FITLD1: Minimum= 2.27500000E+03      Maximum= 1.68650000E+04
samhai> FITLD1: ----------------------------------------------------------------
samhai> FITLD1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
samhai> FITLD1: RA---TAN   317    14 21 59.261     158.50         -1.700    0.00
samhai> FITLD1: DEC--TAN   317    19 13 58.264     159.00          1.701    0.84
samhai> FITLD1: ----------------------------------------------------------------
samhai> FITLD1: Coordinate equinox 2000.00
samhai> FITLD1: Maximum version number of extension files of type HI is   1
samhai> FITLD1: Appears to have ended successfully
samhai> FITLD1: localhost    31DEC06 TST: Cpu=       0.0  Real=       0

I believe the FITS standard requires disk fits files to be padded out to
the nearest multiple of 2880 bytes.  But I'm saying this from fallible
grey matter memory...

The original image size was 212498, which is 73 and some blocks of
2880.  74 x 2880 = 213120, and 213120 - 212498 = 622.

 - Pat (lurker on DAIP list)

-- 
 Patrick P. Murphy, Ph.D.   Senior Software Engineer, ALMA Computing IPT
 NRAO Computing Security Manager       Head, NRAO WebAdmin Working Group
 Home: http://goof.com/~pmurphy/     Work: http://www.nrao.edu/~pmurphy/
 "Inventions then cannot, in nature, be a subject of property."
                                    -- Thomas Jefferson, August 13, 1813