HST Data Handbook for WFPC2

Appendix C:
Observation Logs

---

C.1 Observation Log Files
   C.1.1 Observation Log File Contents (October 1994 version)
   C.1.2 Observation Log File Contents (February 1997 version)
C.2 Retrieving Observation Logs
C.3 Using Observation Logs
   C.3.1 Guiding Mode
   C.3.2 Guide Star Acquisition Failure
   C.3.3 Moving Targets and Spatial Scans
   C.3.4 High Jitter

This Appendix describes the Observation Log Files, also known as OMS or jitter files. These files record pointing, jitter, and other Pointing Control System (PCS) data taken during an HST observation. You can use them to assess the behavior of the HST spacecraft during your observation, and in particular, to evaluate the jitter of the spacecraft while it was taking data. Here we describe the contents and structure of the observation log files, how to retrieve them from the Archive, and how to work with the data they contain.