# UVOTPY: The Swift UVOT Grism Python Software¶

## Users Guide¶

The grisms of the UVOT instrument provide a dispersed image for a region of about 17’x17’ on the Sky. This is a description of the Python software written at UCL/MSSL to help reduce the data. The software extends the earlier Ftool version as distributed in the Heasoft Swift instrument software. This software implements all the recent calibrations, including a correction for coincidence-loss (also known as pile-up) in the photon-counting detectors. It therefore produces a superior product to that from the “uvotimgrism” Ftool.

The calibration files are bundled with the source code for the software (see Fetching the program and data) and you can grab a harcopy of this document PDF.

A simple call can in many cases generate a quick spectrum. The uvotpy module uvotgetspec provides the function getSpec() which only needs the grism data files, including attitude (auxil) files, target position in decimal degrees, and extension with the desired spectral data.