Slitlessutils

Slitlessutils is a Python package to extract spectra from all slitless spectroscopy modes provided by the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). Slitlessutils uses a forward-modeling engine to determine the mapping between a direct image and its corresponding slitless-spectroscopic images. There are two methods for extracting the spectra, which are delineated by the assortments of available HST orients.  Specifically, slitlessutils implements the LINEAR method (Ryan, Casertano, & Pirzkal 2018) for fields with multiple orients, as well as an HSTaXe-style extraction for fields with a single orient.  Additionally, slitlessutils provides several utility functions to prepare observed spectroscopic data for analysis, such as astrometric updates, background subtraction, and cosmic-ray rejection.

As of March 2026, slitlessutils officially replaced HSTaXe, which brings an end to its user support, bug fixes, feature requests, or system upgrades. To learn more are about slitlessutils see the readthedocs documentation.

Installation 

Installation information for slitlessutils can be found in the documentation.