# Description¶

The stack_refs step is one of the coronagraphic-specific steps in the coron sub-package and is part of Stage 3 calwebb_coron3 processing. It takes a list of reference PSF products and stacks all of the per-integration images contained in each PSF product into a single 3D data cube. This operation prepares the PSF images for use by subsequent steps in the calwebb_coron3 pipeline. The image data are simply copied and reformatted, without being modified in any way.

# Arguments¶

The stack_refs step does not have any step-specific arguments.

# Inputs¶

## 3D calibrated images¶

Data model

CubeModel

File suffix

_calints

The inputs to the stack_refs step are multiple calibrated products for the PSF target, produced by the calwebb_image2 pipeline. Each input should be a 3D “_calints” product, containing a 3D stack of calibrated images for the multiple integrations within each exposure.

It is assumed that the stack_refs step will be called from the calwebb_coron3 pipeline, which is given an ASN file as input, specifying one or more PSF target exposures. The actual input passed to the stack_refs step will be a ModelContainer created by the calwebb_coron3 pipeline, containing a CubeModel data model for each PSF “_calints” exposure listed in the ASN file. See calwebb_coron3 for more details on the contents of the ASN file.

# Outputs¶

## 3D PSF image stack¶

Data model

CubeModel

File suffix

_psfstack

The output of the stack_refs step will be a single 3D product containing a stack of all the PSF images from the multiple input exposures. The size of the stack will be equal to the sum of the number of integration (NINTS) in each input PSF exposure. The output file name is source-based, using the product name specified in the ASN file, e.g. “jw86073-a3001_t001_nircam_f140m-maskbar_psfstack.fits.”

# Reference Files¶

The stack_refs step does not use any reference files.