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II. The WISE All-Sky Data Products

4. Ancillary Products

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

The WISE Single-exposure image archive is comprised of 1,491,686 1016x1016 pix @ 2.75"/pix FITS format image sets. Each image set consists of:

WISE 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 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 Single-exposure image archive contains all images in the scans that are part of the WISE All-Sky Data Release scope (V.2.a), regardless of their quality. Many of these framesets suffer from the following problems:

Images showing example frames with many of these problems can be seen in II.4.b.ii, the Single-exposure Image Anomaly gallery.

Most of the low-quality framesets and frames were excluded when selecting frames to constructed the coadded Atlas Images and Source Catalog (V.2.c), but all are present in the Single-exposure image archive. Use this archive with caution.

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:

i. Single-Exposure Image Header Description

ii. Single-Exposure Image Anomalies

Last update: 2012 July 6

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