Starting in July 2012, all drizzled data products obtained from MAST were 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.
An all new ‘development’ version of the software, DrizzlePac 2.0, is now available for download from SSBX.
Current and recent known bugs in DrizzlePac/AstroDrizzle are listed on this page
- To obtain the latest development version (DrizzlePac 2.0), users may install the Ureka-based SSBX build.
- To obtain the same software used in the OPUS pipeline (currently 1.1.16), users may install Ureka.
- To obtain only the new DrizzlePac software while maintaining the official version of Ureka, users may install an add-on following instructions linked on this page.
|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 2.0 release notes|
- Using SExtractor and TweakReg
- Aligning HST mosaics
- Aligning to a non-HST image
- Using DS9 regions to exclude sources
- Using DS9 regions to include/exclude sources
- 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
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