The SWIFT BAT Software Guide Version 6.3 30 ... - HEASARC - Nasa

D.17. BATOCCULTMAP 175
D.17 BATOCCULTMAP
D.17.1 NAME
batoccultmap - compute BAT exposure mask due to occultation
D.17.2 USAGE
batoccultmap infile outfile saofile
D.17.3 DESCRIPTION
batoccultmap computes the fractional exposure in the BAT field of view due to occultation by the
earth, moon and/or sun. The BAT field of view is large enough that any of these bodies may
occult cosmic sources. Since the bodies move with time, the task computes the exposure map as
a function of time and merges the results. This task is used for sky images; if you want to data
selection for the visibility of a single source, use batoccultgti.
The task can be run in two modes. If occultation=“any”, then any portion of the image which
is blocked at any time is masked in the output. If occultation=“fraction”, then the fractional
exposure is computed (a value between 0 and 1).
The user must supply the “SAO” file created by prefilter. This file contains the positions of the
earth, moon and sun as a function of time. The sizes of the earth, moon and sun are configurable.
D.17.4 PARAMETERS
infile [filename ]
The name (and optional extension) of the input image file name.
outfile [filename ]
The name of the output map file. For occultation=“fraction”, the map will range continuously
from 0.0 to 1.0, corresponding to the partial exposure. For occultation=“any”, the map will
be either 0.0 (occulted at some time) or 1.0 (never occulted).
saofile [filename ]
The name of the “SAO” file produced by prefilter. This file should contain the columns TIME,
RA, DEC, ROLL, SAT ALT, MOON RA, MOON DEC, SUN RA, SUN DEC, EARTH RA,
EARTH DEC.
atmdepth = 5.0 [real ]
Thickness of the earth “atmosphere” in kilometers. Points within this thickness are assumed
to have zero exposure.