STScI Calibration Data System

ACS WFC d2imfile

File which describes the column/row correction as a 1-D correction.

The D2IMFILE reference file contains column (or row) width corrections for the ACS WFC chips. Like the NPOLFILE, it is an optional correction which is only added to the FITS and used in coordinate transformations if the filename is specified in the header. It contains a one-dimensional array of column width corrections. In the pipeline, this correction table gets attached to the image as a FITS extension of type ‘D2IMARR.’ Each element in the D2IMARR array specifies the correction (in units of pixels) for every pixel in the column of both science image extensions. It’s applied at the very start of the distortion correction process so that column width-corrected coordinates are used as input to the polynomial and non-polynomial distortion corrections.

To retrieve a file from the archive, click in the file name. For details on how to correctly set up the Archive retrieval options for reference files, check our Help page.

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See the reference file delivery logsheet for more information. These files can also be downloaded directly from the jref directory. If you choose to access the files via this ftp server, keep in mind that there is a known bug in trying to access files via ftp server using Safari. The recommended browser is Firefox.

File Detector Use After Pedigree Delivery # Delivery Date OTFR Start Use Date Comments
x5u17177j_d2i.fits WFC Mar 01 2002 00:00:00 UT INFLIGHT 12622 Sep 16 2013 18:35:57 GMT Sep 16 2013 19:23:46 GMT Column-width correction file for WFC imag