Besides developing the pipeline to reduce the astrometric data from the Hubble Space Telescope, we produced two more general use computer programs, GaussFit and Pickles.
GaussFit was developed as a platform to facilitate the
solution of least squares and robust estimation problems for astrometric
data reduction with data from the Hubble Space Telescope. It provides an
easy and natural way to formulate general nonlinear problems; problems
where the observation equations (equations of condition) contain more than
one observation (the errors-in-variables case); problems with correlated
observations; problems where exact constraints among parameters must be
enforced. Certain robust estimation methods that generalize least squares
to non-euclidian metrics and provide greater immunity against "outliers"
than does the classical least squares method are available. GaussFit runs
both under UNIX and VMS and there is a Macintosh version.
Pickles is a Macintosh program that was first developed
by the HST Astrometry Team as a tool for determining pointings and
rolls of the Hubble Space Telescope when desired target and guide stars
were in the fine guidance sensor "pickles". Because of its
ability to extract and display star positions from the Guide Star Catalog,
ACRS, SAO, AGK3 catalog CD ROMs, pickles is also being used in other
astronomical proj ects. Pickles is a powerful, easy-to-use tool for
visualization of star positions for any purpose.