abssenv -- Calibrate absolute digital sensitivity.
abssenv intable outtable ref_flux
This task calculates digital absolute efficiency for up to 2,000 targets having known flux densities. The absolute efficiency of each target is calculated by dividing its observed count rate (corrected for dark signal, high voltage factor, pre-amp noise, and relative sensitivity--see below) by the target's flux density (integrated over the specified filter's bandpass, and weighted by the filter's transmission curve). This routine also checks the instrument mode of each observation. If it has a simultaneous sky measurement, the sky (which is also corrected for dark signal etc.) is subtracted from the target measurement, otherwise the observed count rate of the target is not changed.
The raw digital count rates are corrected for the dark, pre-amp noise, high voltage factor, sensitivity, and dead time following the formula:
scaled digital count rate = (raw digital count rate / (1. - raw digital count rate * dead time) - dark signal - pre-amplifier noise) / (high voltage factor * relative sensitivity)
'DETECTOB' Object detector ID (int). 'APERTOBJ' Object aperture name (char*10). 'VOLTAGE' High voltage setting (real). 'VGAIND' Gain setting (real). 'THRESH' Discriminator setting (real). 'DET_TEMP' Detector temperature (real). 'DEA_TEMP' DEA temperature (real). 'EPOCH' Epoch of observation (double). 'PTSRCFLG' Point source flag (char*1). We also need the following columns: 'DOBJ' Observed digital count rate (real). 'DOBJ_ERR' Standard deviation of the observed digital count rate (real). 'DSKY' Sky's digital count rate (real). 'MODE' Instrument mode (i.e., SCP, SSP, or ARS) (char*3). 'TRGTNAME' Target name (char*20).
'TRGTNAME' Target name (char*20). 'APER_NAME' Aperture name (char*10). 'COUNT' Scaled digital count rate (real). 'COUNT_ERR' Count rate's error (real). 'REF_FLUX' Reference flux used in this calculation (real). 'SENSITIVITY' Digital absolute sensitivity (real). 'TEMP_KEY' Temperature, as passed from the 'temp_key' parameter (real). 'EPOCH' Epoch (double).
'OBJ_NAME_i' Name(s) of the object, where "i" is an integer between 1 and 5 (char*20). 'FILTER_NAME' Filter name, e.g., F551 (char*4). 'DET_NUM' Detector ID (int). 'FLUX' Flux density (integrated over the filter's bandpass) of the target; density should be in units of erg/sec/sq cm (real).
1. Calculate absolute sensitivities from the input data table xabssenv$input and put results in the output table yabssenv$output while saving the intermediate result in another local table whose name will be announced to the user. The reference flux density table to be used is xabssenv$ref_flux.
hs> abssenv "xabssenv$input" "yabssenv$output" "xabssenv$ref_flux" save=yes