Point Spread Function (PSF)

Here are brief descriptions of the WFC3 Notebooks for Point Spread Function modeling.

HST Point Spread Function

This notebook demonstrates how to generate PSF models for WFC3 observations. This includes retrieving empirical models from the WFC3 PSF Website, generating custom models by stacking stars, and retrieving cutouts from the MAST PSF Database. The notebook includes examples of how to generate stellar catalogs, perform PSF fitting and subtraction, and how to utilize different types of PSF models depending on the available data and science goals. While the examples are focused on WFC3, the notebook can also be used with ACS, WFPC2, and other instruments.

Downloading WFC3 and WFPC2 PSF Cutouts from MAST

The WFC3 team annually releases PSF cutouts (i.e. realizations of the PSF) of sources detected from HST1PASS in WFC3 and WFPC2 observations. These PSF databases contain over 83 million unsaturated and saturated sources, and are publicly available on the MAST Portal. Here, we present a custom MAST API to query, download, and extract PSF cutouts.