Jitter Files

Observation Log files

Since 20 October 1994, a set of pointing and specialized engineering data, called observation logs, has been routinely generated. These files, often referred to as `jitter' files, are produced by the Observatory Monitoring System (OMS), an automated software system which interrogates the HST engineering telemetry and correlates the time-tagged engineering stream with the scheduled events as determined from the Mission Schedule, the seven-day command and event list which drives all HST activities. The observation log contains a plethora of pointing-related information, a necessity for the most accurate evaluation and reconstruction of pointing stability and environment during a given exposure. The intended recipients are General Observers as well as STScI scientists and engineers.