Welcome to the eighth Alpha version of XVista, codenamed "XVista9H"
(dated Feb 23, 2003).

  XVista is a suite of programs for analyzing and displaying 
astronomical images on computers running Unix-like operating
systems and X Windows.  The code is written in ANSI C, and much
of it doesn't make any graphics calls, so you may be able to
use parts of it even on systems that don't have X Windows.

  If you do use X Windows, beware: you must set your display
depth to 8 bits in order to use the image display program "tv"
and the plotting program "xplot".  Sorry about that, but 
the code can only deal with 8-bit deep pixmaps.  

  XVista is designed specifically for reducing large amounts of
imaging data automatically; therefore, it doesn't have much of 
a user interface, and it isn't friendly.  If you like GUIs, you
won't like XVista.  Everything is done from the command line,
with a plethora of command-line options.  It can be unpleasant.
On the other hand, if you are trying to put together a set of
arithmetical operations to be applied in sequence to several
hundred images, it may be just what you want.

  XVista was (and is) written by 

      Richard Treffers, at the University of California, Berkeley
      Michael Richmond, at the Rochester Institute of Technology

It was inspired by a program called "Vista", which was written
by Richard Stover and Todd Lauer at Lick Observatory [1].
We created a set of programs that looked similar, but ran
individually (rather than inside a single process) and was 
designed to work on PCs with only 256 K of memory.  The result
was PC-Vista [2].

  Over the years, we ported the program to the Unix environment
(which wasn't so hard) and X Windows (which was).  We have used
it to acquire, display, and reduce the data taken by a series
of automatic telescopes at UC Berkeley and (recently) Lick
Observatory.  See, for example, our article on BAIT [3], or
papers based on BAIT data [4,5].

  This is the fourth time I've tried to bundle all the XVista code
into a single unit and give it to other people.  I'm sure that
I've made a number of mistakes.  Don't expect that this code will
compile and run "out of the box!"  You'll probably have to fight
with it for a while --- but if you _do_ manage to get it working,
please let me know!  I want to know how I can make it easier to
install, or modify it to support new systems.

  Likewise, if you do use it, and find bugs, please tell me.
I'll even consider adding options or new features, although I don't
promise to do that.
  
  The first thing you should do, after reading this file, and 
unpacking the source code, is to read the "intro.1" (or "intro.ps")
file in the "man1" directory.  That explains the basic usage
of XVista commands.  It might even help to read the PC-Vista
paper [2], although it's seriously out of date in some ways.

  You might also look at the file "TASS.example", which shows
an example C-shell script which uses several XVista commands
to reduce some drift-scan data from a TASS camera.  If you
don't know what TASS is, see

     http://stupendous.rit.edu/tass/tass.shtml

  Any constructive comments and suggestions are welcome.  Please
let me know if you find XVista useful.

                                  Michael Richmond
                                  Feb 23, 2003



  References:

[1] Stover, R. J. 1988, in "Instrumentation for Ground-Based Optical
Astronomy", ed. L. B. Robinson (New York: Springer-Verlag), p. 443.

[2] Treffers, R. R. and Richmond, M. W. 1989, Publications of the 
Astronomical Society of the Pacific, 101, 725.

[3] Richmond, M. W., Treffers, R. R. and Filippenko, A. V. 1993,
Publications of the Astronomical Society of the Pacific, 105, 1164.

[4] Richmond, M. W. et al. 1994, Astronomical Journal, 107, 1022.

[5] Richmond, M. W. et al. 1995, Astronomical Journal, 109, 2121.