PyNOT : corr

This task takes a list of images together with a combined bias frame and a combined flat frame using respectively the --bias and --flat parameters. The command line task accepts wildcards, an explicit list of files, or a file containing a list of files. By default the bias-subtracted and flat-corrected frame is saved to the current directory but this can be changed using the --dir optional parameter. Lastly, in order to make sure that the right header keywords are propagated, make sure to use the command line option --img for imaging data. For spectroscopic data, nothing is needed.

The task pynot corr performs the following steps:

  • Trim overscan
  • Subtract bias frame
  • Divide by flat field frame
  • Calculate error image based on detector gain and read noise
The overscan region is automatically determined from the header (or from the instrument settings). When the overscan region has been trimmed from a raw frame the header will be updated with the following keyword OVERSCAN = TRIMMED together with the two values of pixels that have been removed along the detector x- and y-axes: OVERSC_X and OVERSC_Y.

The easiest way to generate the input for pynot corr is to source it from the file classification table:

%] cat dataset.pfc | grep SPEC_OBJECT > obj.list
%] pynot corr obj.list --dir corr --bias master_bias.fits --flat master_flat_grism4.fits


Alternatively the input can be passed as an explicit list:

%] pynot corr data/file.fits --bias master_bias.fits --flat master_flat_r.fits --img



Example Syntax

pynot corr input


Full example of command line syntax:

pynot corr [-h] [--dir DIR] [--bias BIAS] [--flat FLAT] [--img] input



Overview of parameters

input
List of filenames to correct
Optional Arguments:
--dir: ''
Output directory
--bias: ''
Filename of combined bias frame. If not given, a constant of 0 is used
--flat: ''
Filename of combined flat frame. If not given, a constant of 1 is used
--img: False
Imaging mode