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Data Products

The UIT Project produced several standard data products reflecting various stages of image processing. The files are written in FITS format, and range from the raw scanned data to the photometrically and geometrically corrected images rotated to a standard orientation. Not all images could be fully calibrated however, so not all images include every file type. In addition, tables of aperture and Point-Source-Function (PSF) fitted photometry for point sources in the images are available. These products are summarized below.

A simple naming convention was followed to indicate the camera, mission and frame number for each digital image, e.g. CuvMnnn. The "C" is "N" for the near-UV camera or "F" for the far-UV camera. The "M" indicates the frame count series: it is "0" for Astro-1; "1" for frames taken before a memory reset during Astro-2, and "2" for frames taken after. "nnn" is the three-digit frame number. An appended character ("D", "E", "F"...) indicates the type of data product file.

Further information about UIT data products may be found in Section 4. UIT Data Products of the PASP 109:584-599, 1997 May article describing the UIT mission.

Summary of UIT Image Data Products
Product Image Size Astro-
Sample Filename Description
Astro-1 raw density 2048×2048 No fuv0123d.fits Digitized microdensitometer output. Produced by scans with 20 µm aperture and 20 µm spacing.
Astro-1 raw density up to 4096×4096 No nuv0442sad.fits Alternative digitized microdensitometer output. Produced by scans with 20 µm aperture and 10 µm spacing.
Astro-2 raw density 4096×4096 No fuv2123d.fits Digitized microdensitometer output. Produced by scans with 20 µm aperture and 10 µm spacing.
Linearized, flat fielded 2048×2048 No fuv2123e.fits No good astrometry solution exists so input instrument coordinates for pointing are used. No geometrically corrected images for these images could be produced.
Linearized, flat fielded 512×512 No fuv2123ec.fits Box averaged versions of the "E" files.
Linearized, flat fielded 2048×2048 Yes fuv2123f.fits
Calibrated images for fields with good astrometry solutions. Since images have not been resampled, preferred type for most photometry. SAF files are associated with the UIT1 data that was scanned with 10 µm spacing.
Linearized, flat fielded 512×512 Yes fuv2123fc.fits Box averaged versions of the "F" files
Undistorted, rotated north-up 2048×2048 Yes fuv2123g.fits Calibrated geometrically corrected image.
Undistorted, rotated north-up 512×512 Yes fuv2123gc.fits Box averaged version of the "G" files.

Summary of UIT Photometry files
File Type Sample File Name Description
Aperture photometry fuv2123aph.fits FITS ASCII format containing positions, data, and error estimates for detected point sources. Derived from "E" and "F" files
PSF-fit photometry fuv0123pph.fits Created for selected "G"/"GC" images. Tables are similar to the APH tables.