[daip] WCS

[Ian Pattison]

I'm having a few problems with some images in AIPS. Upon loading the FITS
image via FITLD, I get:

linsta> FITLD1: Task FITLD  (release of 31DEC03) begins
linsta> FITLD1: Create FITLD       .TEMP  .   1 (MA)  on disk  1  cno  853
linsta> FITLD1: IMPARS: BAD NUMBER ON EQUINOX 

The data does load, but when I compare source positions with the original
data (using the ds9 software), there is an offset (~10 asec). The IMHEADER
for the data is:

AIPS 1: Image=M33g Ha   (MA)         Filename=M33G        .IMAP  .   1
AIPS 1: Telescope=INT                Receiver=WFC
AIPS 1: Observer=Zurita,             User #=   60
AIPS 1: Observ. date=27-SEP-2002     Map date=03-AUG-2004
AIPS 1: Minimum=-3.15445117E+04      Maximum= 3.06863652E+04
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
AIPS 1: RA---TAN  6243    01 33 25.605    3844.00      -0.328199    0.00
AIPS 1: DEC--TAN  6206    30 16 55.866    3027.00       0.337330   89.27
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 1950.00
AIPS 1: Maximum version number of extension files of type HI is   1
AIPS 1: Maximum version number of extension files of type PL is   1

I guess, 3 questions - what is the significance of "BAD NUMBER ON EQUINOX"
and could this explain the offset, and why are the coords in 1950, when
the fits header for the original data shows 2000 as the equinox.

I've stuck the original image in 
http://ast.leeds.ac.uk/~ip/public/M33G.FIT incase the fits header can shed 
any light on the situation!

Any comments would be of great help.

Thanks






-- 
******************************************
 Ian Pattison 

 Astrophysics Group 
 School of Physics & Astronomy
 University of Leeds
 LS2 9JT
 United Kingdom

 Tel: +44 (0)113 3433872
 email: ip at ast.leeds.ac.uk
 WWW: http://ast.leeds.ac.uk/~ip

******************************************