Space Telescope Science Institute   11.4 Examples Part IV:  Calibration Overview

11.5 Types of Motions


The Phase II optional parameter OFFSET defines which type of telescope motion will be performed during a pattern. Telescope motions fall into three categories:

The available options for OFFSET are:

Patterns may use the FOM instead of moving the whole telescope, however this is an "available" (not "supported") mode of observation. The FOM is not exactly repeatable, so artifacts on the mirror may appear to move around. Observations requiring small and rapid offsets (or making observations in parallel to another instrument) may benefit from this mode. Note that the astigmatism changes with FOM offsets. Note: flat field calibration reference files are only available for the nominal FOM position.


 11.4 Examples Part IV:  Calibration Overview
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