[Aavso-photometry] FITS Keyword List

[Michael Newberry]

Yep, that's the list. But I've not noticed that particular goof before. I 
guess I haven;t looked at DATE-OBS since maybe the y2k change was made in 
1999. What they say makes no sense.

----- Original Message ----- 
From: "Brian D. Warner" <brian at minorplanetobserver.com>
To: <aavso-photometry at mira.aavso.org>
Sent: Friday, January 04, 2008 6:31 PM
Subject: [Aavso-photometry] FITS Keyword List


> Hi Michael,
>
> OK, that's a start. Going to
>
>  <http://iraf.noao.edu/iraf/web/projects/ccdmosaic/imagedef/fitsdic.html>
>
> The first thing that jumps out is in the first paragraph:
>
>  Most of the keywords defined here will not be used.
>
> Then, going down to the first keyword listed, DATE-OBS, one that is 
> specifically
> covered in the FITS standard document:
>
>   DESCRIPTION:
>    Default date for the observation.  This keyword is generally not used
>    and is DATE-OBS keyword for the start of the exposure on the detector
>    is used.
>
> You have to go down the page to find a different definition of DATE-OBS,
> found in a different file of some sort, that does indicate that it's used.
>
> So, that page could be very confusing.
>
> Of course, one person adopting this convention doesn't solve the problem. 
> As you
> noted, there are many critical values that don't use the same keyword 
> and/or
> formatting. Any software that hopes to be "universal" in that it can read 
> any
> other software must hope that at least the critical, common values will 
> all be
> stored the same way. So far, I haven't found that to be true and have at 
> least
> five different ways to get the date/time from the FITS header, and even 
> that's
> not guaranteed to work.
>
> As some one said about standards, "Surely, you jest."
>
> Clear Skies,
> Brian D. Warner
> Palmer Divide Observatory/Space Science Institute
> http://www.MinorPlanetObserver.com
>
> Collaborative Asteroid Lightcurve Link (CALL)
> http://www.MinorPlanetObserver.com/astlc/default.htm
>
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