DARK_AND_BPM - Measures dark current and creates a new bad-pixel mask for UIST

Description:

This recipe is used to measure the dark current for UIST, using a long-exposure DARK frame. It first finds and bad pixels in the DARK, then measures and reports the dark current. The recipe appends to a tabulation of the dark current in an engineering log file, $ORAC_DATA_OUT/uist_array_tests.log, which it creates with headings if the log does not exist.

Notes:

• The recipe applies thresholds to the dark frame and flags pixels outside these limits as bad. The thresholds are derived from 3-standard-deviation clipped statistics; pixels more than 5 standard deviations above the mean are flagged.

• The bad pixels detected are added into the current bad-pixel mask and then this is filed with the calibration system as a new and current bad-pixel mask.

• The new bad-pixel mask is applied to the original dark frame, whose unclipped mean scaled by the gain and inverse exposure time is the dark current in electrons per second.

Output Data :

• The engineering log $ORAC_DATA_OUT/uist_array_tests.log.

Related Recipes :

ARRAY_TESTS, MEASURE_READNOISE.

Implementation Status:

• The processing engines are from the Starlink package KAPPA.

• Uses the Starlink NDF format.

• History is recorded within the data files.

• Error propagation is not used.