new versions of software

[Stupendous Man <richmond@a188-l009.rit.edu>]

  I have completed some changes to the pipeline software.  The major
ones are:

     1. There is now an extra step in the pipeline, between reducing
            frames (ccdproc) and finding stars (stars).  The new step,
            called "sky", allows the user to measure the sky level --
            same as before -- but also, if desired, to subtract a model
            of the sky from the image.  This will allow us to find stars
            more uniformly across a frame.

            The new facility comes from a new XVista program, called 
            "back".  So it's necessary to get the latest version of
            the XVista package, too.

    2. The pipeline now keeps track of some additional quantities
            (sky level, number of stars found, etc.) for each frame.
            A future release will use this information to make pretty
            plots of a whole night at once -- which will allow us to 
            identify good/bad sections of a night easily.  

    3. One can place limits on several quantities (number of stars found
            in a frame, for example).  If a frame exceeds the limit,
            it may be marked as "bad" and ignored in all subsequent
            processing.

    4. The "photom" program now allows one to correct for differential
            extinction across each frame.  The user must tell the pipeline
            values for the extinction coefficient in each passband.

            This requires using a new version of the "photom" program.

         
  You can read about these in some detail in the "pipeline.html" manual
you can find at

             http://spiff.rit.edu/tass/pipeline/pipeline.html

That URL will also point you to the right place to download the latest
versions of

                 - the pipeline code
                 - the XVista code (the only real change in the new "back"
                          program, so you may be able to get it alone ...)
                 - the "photom" program 
                   
  The bad news is that I checked to see if differential extinction
correction would remove a significant amount of the scatter in the 
DS24 grid photometry, and ... it doesn't.  Sigh.  

  I will not be surprised at all when people try to get the newest
version of the code and find problems.  Please tell me what goes wrong,
and I'll try to fix it.  It may take a few weeks to fix all the bugs,
but I'll do my best.  I have verified the code by running some of the
grid data from DS24 through it....

                                           Michael