4.3 Special Calibration Observations

Data from HST observations are normally provided to the GO after application of full calibrations. Details of the standard calibrations are provided in the Instrument Handbooks (see Section 1.4.4).

In order to obtain quality calibrations for a broad range of observing modes, yet not exceed the time available on HST for calibration observations, only a restricted set, the so-called ‘Supported’ modes, may be calibrated. Other modes may be available but are not supported. Use of these ‘Available-but-Unsupported’ modes is allowed to enable potentially unique and important science observations, but is discouraged except when driven by scientific need. Observations taken using Available-but-Unsupported modes that fail due to the use of the unsupported mode will not be repeated. Use of these modes must be justified prior to the Phase II submission. For details consult the Instrument Handbooks (see Section 1.4.4).

Projects may need to include special calibration observations if either:

•	a Supported mode is used, but the calibration requirements of the project are not addressed by the standard STScI calibration program, or

•	an Available-but-Unsupported mode is used.

Any special calibration observations required in these cases must be included in the total request for observing time and in the Observation Summary of the proposal, and must be justified explicitly. During the Phase II process, proposals to calibrate Available-but-Unsupported modes must be pre-approved by the appropriate instrument team. For details please consult the relevant Instrument Handbook.

Proposers can estimate the time required for any special calibration observations from the information provided in the Instrument Handbooks (see Section 1.4.4). Also, the STScI Help Desk (see Section 1.5) can assist you on this estimate, but such requests must be made at least 14 days before the submission deadline.

The data reduction of special calibration observations is the responsibility of the observer.

Data flagged as having been obtained for calibration purposes will normally be made non-proprietary.