PyNOT : imflat

The imflat task takes a list of a flat images and combines them into a master combined flat frame. The command line task accepts wildcards, an explicit list of files, or a file containing a list of files. The combination is performed using a sigma-clipped mean or median. The threshold of the clipping and the method can be controlled by the kappa and method arguments. Each individual flat frame is normalized by its median value.

The easiest way to generate the input for pynot imflat is to source it from the file classification table for each photometric filter:

%] cat dataset.pfc | grep IMG_FLAT | grep SDSS_r > flat_r.list
%] pynot imflat flat_r.list --output master_flat_r.fits --method median



Alternatively the input can be passed as an explicit list:

%] pynot imflat data/flat1.fits data/flat2.fits data/flat3.fits --output master_flat.fits

or using wildcards:

%] pynot imflat data/flat*.fits --output master_flat.fits



Overview of parameters

input
List of flat images to combine (command line accepts a list of files and wildcards)
Optional Arguments:
bias: 0
Filename of the combined bias frame. (If no file is given, a value of 0 is assumed)
method: median
Method for image combination (options: median/mean)
kappa: 15
Threshold for sigma clipping in bias combiniation

Example Syntax

pynot imflat --bias BIAS -o OUTPUT input


Full example of command line syntax:

pynot imflat [-h] --bias BIAS -o OUTPUT [--kappa KAPPA] [--method {mean,median}] input



Overview of parameters

input
Input file containing list of image filenames to combine
--bias
Filename of combined bias frame [REQUIRED]
--output (-o)
Output filename of combined bias frame [REQUIRED]
Optional Arguments:
--kappa: 15
Threshold for sigma clipping
--method: 'mean'
Method for image combination