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 using AstroDrizzle.
The latest DrizzlePac release notes may be found on this page.
- To obtain the latest version of DrizzlePac (v2.0 and higher), users are recommended to install the new AstroConda distribution. . This version is required to reprocess MAST data products retrieved after Feb 23, 2016.
- DrizzlePac may still be obtained via Ureka, but only the SSBDEV distribution contains v2.0. Ureka has been deprecated, so users are strongly encouraged to switch to AstroConda.
|SUPPORT FOR AUTOMATED MOSAIC BUILDING||Align sets of images into a large mosaic in one step Read more|
|IMPROVED SKY MATCHING||Produce seamless mosaics using new sky matching techniques. More details can be found in an example where these techniques are compared.|
|ACS TIME-DEPENDENT DISTORTION CORRECTION||Supports the new ACS distortion calibration: Only DrizzlePac 2.0 is able to interpret and apply the latest ACS/WFC distortion reference files Read more|
|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|
|ALIGN 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|
|ALIGN HST IMAGES TO NON-HST IMAGES||Allows undistorted non-HST images to be used as references for aligning and drizzling HST data. Read more|
|NEW SUPPORT FOR EXCLUSION INCLUSION REGIONS||Select specific areas of interest to use for alignment. We provide an example where these techniques are discussed.|
|FULL SET OF UPDATES||Please see the DrizzlePac release notes|
- Optimizing Pixfrac (*NEW*)
- Creating Mosaics (*NEW*)
- Using SExtractor and TweakReg
- Aligning HST mosaics
- Aligning to a non-HST image
- Using DS9 regions to exclude sources when aligning
- Using DS9 regions to include/exclude sources
- Using new sky matching methods with AstroDrizzle
- WFC3/UVIS: Optimizing Image Alignment for Multiple Visits
- WFC3/IR: Optimizing Image Sampling for a Single Visit
- ACS/WFC: Optimizing Image Alignment for Multiple Visits
- ACS/WFC: Optimizing Image Sampling for a Single Visit
- WFC3/UVIS: Aligning Images in Different Filters by Defining an Output Reference Frame
- WFC3/UVIS: Alignment of Sparse Fields Using Headerlets
- WFPC2: Aligning and Drizzling WFPC2 Images
- SExtractor Catalogs to Align ACS/WFC Images
- Quick Start Guide (*NEW*)
- DrizzlePac Handbook
- Instrument Handbooks
- Video Tutorials for Beginners
- DrizzlePac Brochure AAS 225