About DrizzlePac

Overview

DrizzlePac is a software package for aligning and combining HST images, which brings an array of new features and algorithmic improvements over the prior, widely used MultiDrizzle software. Starting in July 2012, all drizzled data products obtained from MAST are produced with AstroDrizzle. An abbreviation for Astrometric Drizzle, AstroDrizzle was designed from the ground-up to substantially improve the handling of distortion in the image header World Coordinate System.

AstroDrizzle removes geometric distortion, corrects for sky background variations, flags cosmic-rays, and combines images with optional subsampling. Drizzled data products from MAST are generated for single visit associations only. To combine data from additional visits, TweakReg may be used to update the image WCS using matched source lists. Once the full set of images of a given target are properly aligned, they may be combined with AstroDrizzle.

News

February 2024: Drizzlepac’s readthedocs has been reorganized to more clearly describe its functionality and some common workflows. This change may affect links in the DrizzlePac Handbook, which will be resolved in the next version. For questions, please contact the HST Help Desk.

September 2022: Updated DrizzlePac Installation Instructions

To install Drizzlepac and related tools, please follow the instructions in the stenv Github repository, which contains the latest versions of the Space Telescope Calibration Pipeline and Analysis Tools. stenv replaces the previous AstroConda software distribution, which is no longer supported.

August 2022: "Improved Absolute Astrometry for ACS and WFC3 Data Products"

A new report (ACS ISR 2022-03WFC3 ISR 2022-06) describes the updated WCS solutions in MAST data products and highlights two new types of "Hubble Advanced Products".

August 2021: Drizzling Multi-Epoch Datasets

Prior to combining with AstroDrizzle, multi-epoch observations with ACS/WFC, WFC3/UVIS, or ACS/SBC should be corrected for changes in the detector sensitivities ~0.1-0.2% per year.  A Jupyter Notebook shows how to ‘equalize’ the count rates in WFC3/UVIS images acquired several years apart to create drizzled data products for a selected reference epoch.

February 2021: Updated DrizzlePac Handbook, now available in HDox

January 2019: DrizzlePac notebook tutorials released. See WFC3 STAN, Issue 28 for details.

 

About DrizzlePac

To install Drizzlepac and related tools, please follow the instructions in the stenv Github repository, which contains the latest versions of the Space Telescope Calibration Pipeline and Analysis Tools.

This repository replaces the previous AstroConda software distribution, which is no longer supported. The DrizzlePac notebook tutorials, developed in 2019, were based on older versions of software; they will be updated in the future for full compatibility with the stenv environment. While the notebooks may not run seamlessly in the new environment at present, the workflow is still relevant and may only require minor tweaks in syntax. For questions, please reach out to the DrizzlePac help desk through email or the online portal.

Questions may be addressed to the STScI Help Desk website: hsthelp.stsci.edu