[iaufwg] correction to the FITS Standard

[William Pence]

Dear IAU-FWG members,

I have updated the copies of the FITS Standard document available on the 
FITS Support Office web site (at 
http://fits.gsfc.nasa.gov/fits_standard.html) to fix a minor 
transcription error.  The last line of table 8.1 on page 74, has been 
modified so that LONPOLEa and LATPOLEa now correspond to the FITS 
keywords PVi_3a and PVi_4a, not with PVi_1a and PVi_2a.  This brings the 
FITS Standard into agreement with the similar Table 1 in the WCS Paper 
II on celestial coordinates.

regards,
Bill Pence

Steve Allen wrote:
> On Mon 2008-09-08T11:09:54 -0400, William Pence hath writ:
>> The question below was sent to the FITS support office.  Is Table 8.1 in
>> the FITS Standand incorrect?  Should it state that LONPOLEa and LATPOLEa
>> are associated with PVi_3a and PVi_4a instead of PVi_1a and PVi_2a?
> 
> I think the erudite response is "oh rats",
> and the answers are yes and yes.
> 
>> Table 8.1 section 8, page 74 lists for the native longitude and latitude
>>   of the celestial pole the keywords LONPOLEa= and LATPOLEa= which,
>> according to the table is equivalent to PVi_1a and PVi_2a.
>> However, in the same table these keywords were previously attached to
>> the fiducial point. Also Calabretta and Greisen use PVi_3a and PVi_4a in
>> their article 'Representations of celestial coordinates in FITS'.
>> Please can you inform me about what is right (i.e. standard FITS) in
>> this case?
> 
> Plainly table 8.1 on page 74 of the standard is intended to be
> entry for entry identical with WCS Paper II, Table 1, on page
> 1079 of the A&A journal.
> 
> --
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-- 
____________________________________________________________________
Dr. William Pence                       William.Pence at nasa.gov
NASA/GSFC Code 662       HEASARC        +1-301-286-4599 (voice)
Greenbelt MD 20771                      +1-301-286-1684 (fax)