whtfocusrun Script

A close companion to this script is  'ifocusrun', a script that takes a series of exposures, each time stepping the instrument 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 'WHT-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 whtfocus commands. The number of reads in the MNDR cycle may be modified using the numreads commands. 

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 telescope focus for the first exposure in the sequence - should be a real number specified in mm (typically to a couple of decimal places).

focus_increment specifies the amount to change the focus on each new exposure - should be a real number specified in mm (typically to a couple of decimal places).