Input Files

KBMOD expects Vera C. Rubin Science Pipelines calexp-style data. These can be provided as a set of multi-extension FITS files, references to the data’s location on a Butler instance, or a saved WorkUnit.

Butler

TODO

WorkUnit

The WorkUnit objects provide functions for writing to and loading from files. In addition to image data, the WorkUnit includes configuration data for the run and all necessary metadata (e.g. the WCS). To load a WorkUnit from a file, use:

my_wu = WorkUnit.from_fits(input_filename)

FITS Files

If loading data from raw FITS files, these must be Vera C. Rubin Science Pipelines calexp-style FITS files that contain:

• photometrically and astometrically calibrated single-CCD image, usually referred to as the “science image”,

• variance image, representing per-pixel noise levels, and a

• pixel bitmask

stored in 1st, 2nd and 3rd header extension/plane respectively. The zeroth header extension is expected to contain the image metadata. A single FITS file can be loaded with the load_deccam_layered_image() function, which takes the file name and a PSF object and produces a LayeredImage.

To build an ImageCollection from multiple FITS files, use the class’s fromDir() function. The images within a single run are expected to be warped, i.e. geometrically transformed to a set of images with a consistent and uniform relationship between sky coordinates and image pixels on a shared pixel grid.