Chapter 4: Data Analysis

This chapter provides insight and instructions for the analysis of FGS astrometry data. This includes the reduction of multi-epoch Position Mode observations (used, for example, in the determination of an object’s parallax), multi-epoch Transfer Mode observations (used to derive a binary system’s orbital parameters), as well as the detailed inspection of the data from a single exposure or observation. The software (i.e. source code) for analyzing both Position Mode and Transfer Mode observations and pipeline products can be downloaded from the FGS Website. These tools are written in standard Fortran and/or C and operate in the UNIX environment. A significant amount of this software was provided to STScI by the Space Telescope Astrometry Science Team (STAT) at the University of Texas and Lowell Observatory. However, please note that many of the tools produce graphical displays by calls to the SM1 library, for which you may require a site license. STScI is working to replace the SM with a publicly licensed package. Until this is accomplished, if you need to use a non-SM graphics package, modest alterations to the source code will be necessary. Check the STScI FGS Website for updates.

1 SM is an interactive plotting program written by R. Lupton and P. Monger, and is copyright (C) 1987-2000 by R. Lupton and P. Monger.