Step Arguments

The background image subtraction step has four optional arguments. The first two are used only when the step is applied to non-WFSS exposures. They are used in the process of creating an average background image, to control the sigma clipping, and are passed as arguments to the astropy sigma_clip function:

--sigma

When combining multiple background images, the number of standard deviations to use for the clipping limit. Defaults to 3.

--maxiters

When combining multiple background images, the number of clipping iterations to perform, or None to clip until convergence is achieved. Defaults to None.

--save_combined_background

Saves the combined background image used for background subtraction. Defaults to False.

--wfss_mmag_extract

Only applies to Wide Field Slitless Spectroscopy (WFSS) exposures. Sets the minimum (faintest) magnitude limit to use when selecting sources from the WFSS source catalog, based on the value of isophotal_abmag in the source catalog. Defaults to None.