NAME

ssa_err.pl - Generate Centroiding Offsets from Dark Current Map

SYNOPSIS

ssa_err.pl [-help]

OPTIONS

-help: print this usage and exit.

DESCRIPTION

This code calculates the mean centroiding offsets for each pixel on the ACA CCD. Offsets are primarily caused by irregularities in the dark current map such as flickering hot pixels. These offset arrays are used by SAUSAGE to calculate the rms centroiding error over an observation specific dither region. Regions with a large rms error are avoided.

EXAMPLES

The bulk of the run options are controlled by the parameter file, sea.par.

  plist sea  : print the current parameter settings

The below example will run the offset calculator on half of the 2004171 dark current map and deposit the resulting ASCII data file in the current working directory.

  pset sea cal_dir /proj/sot/ska/acacal/2004171/
  pset sea out_dir $PWD
  pset sea out_ext .dat
  pset col_start 0
  pset col_finish 511
  ssa_err.pl

NOTES

Depending on computational speed, $par{n_samples} can be increased for improved resolution. The current, recommended value is 50. Which specifies 50 random readouts centroided out of an entire simulated observation containing thousands of generated readouts. This parameter should be consistant across any single array run.

If you plan to concatenate output files from multiple runs it is advisable to only adjust the column space of the run and allow the row space to cover the length of the CCD. This allows for straight concatenation without reordering before IDL reforms the array to 2D.

AUTHOR

Brett Unks (brett@head.cfa.harvard.edu)