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Space Telescope Imaging Spectrograph
STIS-16

ACTIVITY TITLE: CCD Image and Pointing Stability

ID: STIS-16

APPLICABLE SMOV REQUIREMENTS: L.10.4.5.3.5

DESCRIPTION: Check image motion using external star field and internal aperture illuminated by lamp. Images of star field and 0.1x0.09 aperture are alternately recorded for two orbits. This activity is to be executed after large angle maneuver predicted to induce large thermal change that might affect focal plane-to-STIS and internal STIS optical stabilities. Advice should be sought from thermal engineers for worst-case thermal change. If possible, this activity will be done using an established astrometric star field, such as those in NGC 188 or M35.

IMPLEMENTATION METHOD: Stored commanding

DEPENDENCIES: Must execute after STIS-13. Large angle maneuver expected to induce worst case motions for focal plane-to-STIS and STIS internal must be done just before this activity.

DURATION: 2 external orbits

DATA REQUIREMENTS: 0.5 Gbits

ANALYSES & EXPECTED RESULTS: Typical motion of focal plane to STIS and/or STIS internal motion is significant during the first orbit, mostly in the first third of orbit after a large angle maneuver. Measurements of field format using stellar images and the 0.1x0.09 aperture illuminated by a lamp. IDL software tools will be used with Don Lindler participation.

COMMENTS: Since new instruments have been added and modifications have been done to HST, this is required to confirm that no additional thermal motions have been induced by the changes.

AUTHOR/telephone/email: Ted Gull/ 301-286-6184/Theodore.R.Gull@NASA.GOV

DATE: September 25, 2007