This page is part of the ING manual WHT-INGRID-2:
INGRID IMPB Software Operations Manual
| Usage: | ifocusrun num_exposures int_time num_coavgs
start_offset focus_increment
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| Category: | Observing System Scripts
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| Description: | This script takes a series of exposures at different
instrument
focus positions. The acquired data may be analysed using the INGRID 'Quick
Look' Data Reduction facility to determine the best instrument focus.
A close companion to this script is 'whtfocusrun', a script that takes a series of exposures each time stepping the telescope focus. See "Observing with INGRID" for advice on the best usage of these scripts. The script generates multiple output files of type scratch, named 's1.fit' .. 's<n>.fit' where <n> is the total number of exposures. For easy differentiation each output file has its OBJECT header item tagged 'I-FOCRUN-<i>/<n>' where <i> is the index of the exposure in the range 1..<n>. In addition to the parameters normally configurable when acquiring data, users may specify a starting focus position, a focus increment and the total number of exposures to take. Internally the script builds on the services provided by the Instrument Support Platform (ISP) scratch and ifocus commands. The number of reads in the MNDR cycle may be modified using the numreads commands.
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| Arguments: | num_exposures determines the number of
exposures in the sequence.
int_time is the MNDR integration time specified in seconds to the nearest millisecond. The minimum integration time is determined by the speed with which the SDSU Controller can scan the Hawaii detector array (typically about 1.2 seconds). num_coavgs specifies the number of coaverages in the observation sequence - should be a positive integer in the range 1 to 100. start_offset specifies the instrument focus for the first exposure in the sequence. focus_increment specifies the amount to
change the focus on each new exposure.
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| Examples: | ifocusrun 16 5 1 -800 100 takes sixteen, five second exposures, starting at a focus position of -800 microns and stepping 100 microns after each exposure. During the entire sequence frame coaveraging is off (set to 1). |