CIRPASS Calibration

For all queue/service observations, a set of standard calibrations (the "baseline calibrations") will be taken by Gemini Staff. The baseline calibration set varies from instrument to instrument and from mode to mode.

Applicants should not include time for baseline calibrations in their proposals. If additional calibrations are deemed necessary by applicants, for example to achieve a precision beyond that achievable via the baseline set, then these must be included explicitly as part of the Phase I proposal and Phase II science program. Telluric standard observations for spectroscopy are the only Baseline calibrations that must be included as part of a Phase II program

Baseline calibration data may be shared between programs and will be distributed to the users as part of their dataset. Any time used between the hours of nautical sunset and sunrise to obtain baseline calibrations will not be explicitly charged to the program but will be charged to the partner country whose NTAC recommended time (i.e. it is part of the time accounting used to balance partner usage). The time will be charged in proportion to the number of programs that receive the calibration data. Any time required for additional calibrations requested by the PI will be charged to that particular program.


Measurement Type Notes
Bad pixel mask Derived for run from extant data. 
Calibration unit flat field Dome and GCAL flats are taken nightly in each instrument configuration used. 
Dark Taken for each exposure time used. Short darks (~1 sec) are used to help identify bad pixels.
Wavelength calibration OH sky lines from the data themselves provide the primary wavelength calibration. Arc lamp measurements obtained during initial engineering at the start of the run may also be available. 
Telluric standard star An appropriate telluric standard should be chosen by the PI and included in the Phase II program before and after each observation. When the observation is executed in the queue, the astronomer will select one of the two for the Baseline calibration. The PI will not be charged for one telluric standard for each observation. The PI should take care to select a star of the appropriate spectral type and brightness at an airmass that will match the science target. For help selecting telluric standards, see the NIRI Spectroscopic standards page.
Flux standard star Not included as part of the baseline calibration set. Please include spectrophotometric standards in your proposal if needed.
Atmospheric extinction Not included as part of the baseline calibration set.
Point Spread Function star Not included as part of the baseline calibration set.
World coordinate system Automatically included for each CIRPASS image. The WCS is accuracy is TBD. 
Focal plane mask image Not applicable.
Special standards Not applicable.

[Science Operations home] [CIRPASS home]

Last update August 26, 2002, Phil Puxley