Wide Field and Planetary Camera 2 Instrument Handbook for Cycle 14

7.12 Two-Gyro Mode

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At some future date HST may be operated with only two gyros, hence causing additional spacecraft jitter and degradation of the effective PSF. Other potential impacts of operating in two-gyro mode are decreased visibility periods between occultations, and restricted target availability during the year. It is also possible that the pointing stability between exposures may be slightly poorer.

Please see the Two-Gyro Mode Handbook for additional discussion.