Subject: FOLLOW UP: What I am using FITs for . . .

From: Steve Welch <sjw at solitaire.cv.nrao.edu>
Date: 10 May 1995 08:26:39 GMT

Earlier I posted a msg asking for information about any FITs ftp sites.  Thanks
to Donald C Wells for his swift reply and suggestion of 

http://fits.cv.nrao.edu/  and  ftp://fits.cv.nrao.edu/fits/

Donald suggested that I post more details about what I am doing - so for
general interest, and in case anyone else has done anything similar . . .
	
I am part of a team of people working on an instrument for an X-ray telescope.
The CCDs and other 'front-end' parts of the telescope are being provided by
other institutions, and my institution is providing (amongst other things)
a hardware digital preprocessor for data reduction.  A little while ago, some
extensive testing was done with a 'bread-board' model of the telescope, and I
have access to a stack of data in FITs format.  I am currently designing a
simulator of the telescope front-end for us to use at our lab for hardware
testing.  This simulator will be a mixture of hardware (a dedicated VME card
designed by myself and a colleague) and software (mostly C, executing in
VxWorks (a real-time UNIX extension).  

Now for FITs . . .  Prior to the testing of the whole telescope, CCD images
were just made up, and could be useful engineering test patterns.  While this
is still true, now that there is realistic data available, we can do better.
To make the design of the real-time software easier, I would like to read the
FITs data in (offline) and write it into a new file type, where the data is
simply a long list of integers, one to a line.  The integers will be the 
energy of the pixels, and their position in the list will imply the coordinate
eg in the simplest of the several cases, first in the list is the energy of
the bottom leftmost pixel, and so on along the bottom row, and so on.

I am surely not the first to do this sort of thing, but if it turns out that
I am the first subscriber to this list to do so - I'll post a follow up to
give my findings.

Regards

Steve Welch

sjw at mssl.ucl.ac.uk

---

From: Mike Corcoran <corcoran at barnegat.gsfc.nasa.gov>
Date: Thu, 11 May 1995 08:18:40 -0400

Steve,

You might also try looking at

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

for samples of FITS files and conventions adopted by the high energy
group at Goddard and used by a number of X-ray astronomy missions
(ROSAT, ASCA, XTE...).

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
********************************************************************************