The files here describe the VISTA VIRCAM Camera. We need to specify the pixel dimensions, gain, saturation and readout noise.
In this directory we must have a fits file for each ccd. Together these describe the VISTA camera. The buildDetectors script is modified from obs_necam to make the fits file for each ccd.
The fits files currently present are made from an obs_subaru example fits files for each CCD and modifying key values.
Saturation values are taken from :
http://casu.ast.cam.ac.uk/surveys-projects/vista/technical/linearity-sequences
and gain values are taken from
http://casu.ast.cam.ac.uk/surveys-projects/vista/technical/vista-gain
The median gain is 4.2. Since gain is electrons per count the effective gain value is different for exposures and stacks. Since stacks are produced from six exposures:
gain_{stack} = gain_{exposure} * 6