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VIII. Post-Cryo Data Release

2. Post-Cryo Data Products

b. Single-Exposure Images, Bit Masks, Uncertainty Maps

The 2013 Post-Cryo Release image archive contains 901,271 image sets that were produced during second-pass data processing that used improved calibrations and data reduction algorithms. The Preliminary Post-Cryo Release image archive contained 901,274 images sets that were produced during first-pass processing. The 2013 Post-Cryo Release Single-exposure images supersede the Post-Cryo Preliminary Release images.

The 2013 Post-Cryo Release contains three fewer image sets than the Post-Cryo Preliminary Release because the framesets corresponding to these image sets failed processing during the second-pass. In one case, scan/frame number 09866a144, the failure was caused by severe image smearing. In the remaining two cases, 09918a195 and 10196a265, W1 images were lost during downlink and second-pass processing required both W1 and W2 images to be available for successful completion.

Each element of the Post-Cryo Single-exposure image sets is a 1016x1016 pix @ 2.75"/pix FITS format image. Each image set consists of:

WISE Post-Cryo Single-exposure images are in the Flexible Image Transport System (FITS) format and follow the World Coordinate System (WCS) standard for astronomical image data.

Single-exposure Image products have filenames as follows:

where BAND = 1, 2, 3, or 4, and frameID is a unique identification string pertaining to the frameset. FrameID has the form SSSSxMMM, where SSSSSx is the identifier of the scan in which the framset was taken, scan_id, and MMM is the frame number, frame_num, within the scan. BAND and frameID are variables that match the values of keywords with the same name in FITS headers. The WISE Single-exposure Image FITS header content is described in II.4.a.i.

The Post-Cryo Single-exposure (L1) Frame Metadata Table provides additional information about the WISE Single-exposure image sets including much of the image header content and derived statistical and quality assessment information pertaining to both the Single-exposure images and extracted source database. This metadata table can be searched using the IRSA Gator catalog search engine.

CAUTION: The Post-Cryo Single-exposure image archive contains all images taken during Post-Cryo operations, regardless of their quality. Many of these framesets suffer from the following problems:

Examples of frames that show many of these problems can be seen in the All-Sky and 3-Band Cryo Release Single-exposure Image Anomaly galleries in II.4.b.ii and VII.2.d.i.

You can identify Single-exposure image sets that are of good quality using several of the keywords in the FITS headers and/or values in the metadata tables as follows:

Last update: 2013 March 14

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