[daip] 1983 data header

[Data Analysts]

Hi,

I'm not quite sure who to send this to, so daip gets it.

Regards,

Jason

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>From harriet at mrao.cam.ac.uk Thu Jul 10 07:56 MDT 2003
Date: Thu, 10 Jul 2003 14:56:37 +0100 (BST)
From: Harriet Cullen <harriet at mrao.cam.ac.uk>

Dear Analysts

I have recently retrieved some fairly old (1983) data from the VLA
archive.  I think because of the data's age AIPS is having some problem
reading the header properly, for example the co-ordinate equinox was 0.0.
However the main problem is fixing the channel frequencies - in the header
the data has 31 channels but the coordinate value is given for pixel 64.
Knowledge of the systemic velocity for this galaxy means this must be
wrong and the frequency must correspond to approx channel 15, ie in the
centre of the bandwidth.  What I was wondering was how I can determine
exactly which channel it corresponds to.  I include the header below for
clarification.  Any light you could shed on this puzzle would be hugely
appreciated.

Thank you very much for your help

regards
Harriet

AIPS 1: Image=N4647     (MA)         Filename=A116_2      .ICL001.   2
AIPS 1: Telescope=VLA                Receiver=VLA
AIPS 1: Observer=AK89                User #=  892
AIPS 1: Observ. date=17-JUL-1983     Map date=08-JUL-2003
AIPS 1: Minimum=-8.86790082E-03      Maximum= 7.82141238E-02 JY/BEAM
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
AIPS 1: RA---SIN  1024    12 41 01.100     512.00         -8.000    0.00
AIPS 1: DEC--SIN  1024    11 51 21.000     513.00          8.000    0.00
AIPS 1: FREQ        31   1.4136972E+09      64.00  4.8828125E+04    0.00
AIPS 1: STOKES       1   1.0000000E+00       1.00  1.0000000E+00    0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox    0.00
AIPS 1: Map type=NORMAL              Number of iterations=    2000
AIPS 1: Conv size=  63.20 X  41.40   Position angle=  60.34
AIPS 1: Rest freq      0.000         Vel type: OPTICAL wrt YOU
AIPS 1: Alt ref. value  0.00000E+00  wrt pixel   64.00
AIPS 1: Maximum version number of extension files of type CC is  31
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
AIPS 1: Keyword = 'WTNOISE '  value =  1.198353E+00
AIPS 1: Keyword = 'PARANGLE'  value = -4.843205E+01
AIPS 1: Keyword = 'ZENANGLE'  value =  5.459758E+01

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