Subject: RE: "OGIP FITS" standard

From: pence at tetra.gsfc.nasa.gov (William Pence)
Date: Fri, 12 Mar 93 18:21:43 EST

Lucio Chiappetti wrote:

>In a recent meeting an ESTEC colleague mentioned the "OGIP FITS conventions"
>and the case for compatibility with them. He also voluntereed to distribute
>some related documentation.
>
>Since I have never seen such topic discussed on FITSBITS or WGAS (I am
>posting this to both lists) I would like to know more :

As a member of the OGIP, I will attempt to give an unofficial answer to the
questions that were presented.  First, OGIP stands for the 'Office of Guest
Investigator Programs' at NASA/Goddard Space Flight Center.  The OGIP provides
guest observer support for various high-energy astrophysics missions including
the Compton Gamma-Ray Observatory, ROSAT, Astro-D, and XTE.  Also under the OGIP
is a group called the HEASARC which, among other things, is developing and 
promoting multimission FITS format standards for use by these missions.  

>  - Are these OGIP conventions a "private" convention of GSFC, or it is
>    intended to propose them as a draft standard in the traditional FITS
>    way ?

Our goal is to develop standards which can be used throughout the
high-energy astrophysics community, not just within the OGIP.   We are
following a 2-pronged approach to develop the standards.  On one hand,
we are designing specific FITS formats for use by particular missions.
These formats then serve as a model for future missions with similar
types of data.  On the other hand, we are beginning to draft general
guidelines for the FITS format for certain general classes of
high-energy data, such as light curves, spectra or event data. 

>  - Is the related documentation restricted in access or usage ?
>    And if not is it available electronically ?

The documentation will be freely available.   One distribution channel
that the HEASARC uses is it's biannual Journal called "Legacy" which
usually contains some FITS related articles.  Legacy is currently sent
to a very wide distribution list, both within and outside the
high-energy community.  If anyone wishes to be added to the
distribution list, and/or receive copies to the first 2 issues that
have been published, they should send a request to

        HEASARC::TYLER or tyler at heasrc.gsfc.nasa.gov

In the future, we plan to make each Legacy article available electronically,
but this will probably not be available for a few more months.

>  - How stable are those conventions ? I mean, are they frozen ? Are
>    they liable to change duirng development dramatically ? etc. etc.

We are currently trying to reach an internal concensus withing the OGIP
for some some of these standards.  In particular, we will soon have a
draft document on the standard formats for light curve and event data
files that are used in timing analysis.  So the standards are certainly
not frozen, but as we beginning using these formats within the OGIP, it
will naturally become more difficult to make major changes.

>  - Are these conventions open for discussion in the context of future
>    missions in which European and Eastern countries may be involved
>    (e.g. SAX, Spektrum-RG, XMM etc.) ?

Yes, we will certainly welcome discussion on our drafts.  It would be in
everyone's interest to try to reach agreement on standards that
all high-energy research groups could use.

Bill Pence
HEASARC

---

From: Lucio Chiappetti <lucio at ifctr.mi.cnr.it>
Date: Mon, 15 Mar 93 19:25:26 ITA

On Fri, 12 Mar 93 17:40:58 -0500 William Pence said:
>the Compton Gamma-Ray Observatory, ROSAT, Astro-D, and XTE.  Also under the

>all high-energy research groups could use.

  I have received so far, concerning my posting about "OGIP FITS", the
  above "unofficial" reply from Bill Pence, and another (official ?)
  reply by Mike Corcoran (concerning ROSAT, with some additional material),
  which I presume was posted only to me.
  Both replies stated interest in continuing a discussion on this.

  What is the best way to do it ? Over WGAS and/or fitsbits ? Over some
  other list ? Or just privately ?
  I'd like to solicit comments from other possibly interested parties.

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