Subject: FITS 'extensions'

From: rppass at tasc.com (Ralph P. Pass)
Date: 3 Aug 1995 13:25:35 GMT

I have looked at some of the FITS files that are generated by various
CCD camera interface programs.  I notices many non-defined 
(non-standard??) parameters.  While the FITS document allows for this
should we not standardize them so that at least we know what the
parameters mean and what form they are??

For example, I have seen UT and TIME-OBS for the time.  I have seen
the values after these labels being in single quotes. I have seen
them in the form with colons (:) separating the hours minutes seconds
and with slashes (/).

It is apparent that the FITS format is flexible but has grown into a 
non-standard.  

I, of course, would like to suggest a set of unofficial standards for
many of the extensions I have seen (just to try to control the 
proliferation).  Of course, getting the software suppliers to change to 
these suggestions might prove to be difficult.

On the other hand, how about FITS having a set of defined 'unofficial' 
extensions??

Just some thoughts

Ralph Pass
rppass at tasc.com

a

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From: Mike Corcoran <corcoran at barnegat.gsfc.nasa.gov>
Date: Fri, 4 Aug 1995 10:04:53 -0400

> On the other hand, how about FITS having a set of defined 'unofficial' 

The High Energy Astrophysics Science Archive Research Center (HEASARC)
at GSFC came to a similar conclusion.  The HEASARC has the
responsibility of archiving data from space-based high energy astronomy
missions.  We've adopted FITS as our archiving format, but we soon
realized that non-conventional usages made analyzing the data a real
pain. To help remedy this we've tried to promote some conventions.  You
can get more information about these conventions from the web page

http://heasarc.gsfc.nasa.gov/docs/heasarc/ofwg/ofwg_intro.html

for more information about the conventions we've recommended.  

best regards

Mike Corcoran

********************************************************************************
Dr. Michael F. Corcoran
High Energy Astrophysics Science Archive Research Center
Goddard Space Flight Center
Greenbelt, MD 20771
corcoran at barnegat.gsfc.nasa.gov
LHEAVX::CORCORAN
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