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 toNone
.--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 toNone
.