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Hubble Space Telescope
DrizzlePac

**UPDATE JANUARY 2019**
New python drizzling tutorials are now available as Jupyter Notebooks.



DrizzlePac is 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.

 
SOFTWARE INSTALLATION

    DrizzlePac may be obtained by installing AstroConda . The most recent software versions for both linux and osx are listed here and the latest release notes may be found here.
    Instructions for setting up your computing environment to use the DrizzlePac software are described in the following Jupyter Initialization notebook.
 
DRIZZLEPAC FEATURES

AUTOMATED MOSAIC BUILDING Align sets of images into a large mosaic in one step Read more
IMPROVED SKY MATCHING ALGORITHMS Produce seamless mosaics using various sky matching techniques. More details can be found in an example where these techniques are compared.
MITIGATION OF FALSE DETECTIONS Select point-source targets for alignment based on sharpness/roundness and use of DQ masks to limit inclusion of artifacts/cosmic-rays. Read more
ALIGNING DIFFERENT HST CAMERAS Specify separate source finding parameters for input and reference images to optimize source detection from images taken with different HST cameras. Read more
ALIGNING HST IMAGES TO NON-HST IMAGES Allows undistorted non-HST images to be used as references for aligning and drizzling HST data. Read more
USING EXCLUSION REGIONS WHEN ALIGNING IMAGES Select specific areas of interest to use for alignment. We provide an example where these techniques are discussed.
 
EXAMPLES & TUTORIALS

 
RESOURCES


 
SUPPORT

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