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  1. Data Management
  2. DM-4998

Fix rotation for isr in obs_subaru

    Details

    • Type: Bug
    • Status: Done
    • Resolution: Done
    • Fix Version/s: None
    • Component/s: obs_subaru
    • Labels:
      None
    • Templates:
    • Story Points:
      2
    • Sprint:
      Science Pipelines DM-W16-6
    • Team:
      Data Release Production

      Description

      Approximately half of the HSC CCDs are rotated 180 deg with respect to the others. Two others have 90 deg rotations and another two have 270 deg rotations (see HSC CCD layout) . The raw images for the rotated CCDs thus need to be rotated to match the rotation of their associated calibration frames prior to applying the corrections. This is accomplished by rotating the exposure using the rotated context manager function in obs_subaru's isr.py and the nQuarter specification in the policy file for each CCD. Currently, rotated uses afw's rotateImageBy90 (which apparently rotates in a counter-clockwise direction) to rotated the exposure by 4 - nQuarter turns. This turns out to be the wrong rotation for the odd nQuarter CCDs as shown here:

      top left = raw exposure as read in
      top right = flatfield exposure as read in
      bottom left = incorrectly rotated raw exposure prior to flatfield correction

        Attachments

        1. ccd100_nQuarter3.png
          257 kB
          Lauren MacArthur
        2. ccd100_nQuarterFix.png
          895 kB
          Lauren MacArthur

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                • Assignee:
                  lauren Lauren MacArthur
                  Reporter:
                  lauren Lauren MacArthur
                  Reviewers:
                  Bob Armstrong
                  Watchers:
                  Bob Armstrong, John Swinbank, Lauren MacArthur
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                  Dates

                  • Created:
                    Updated:
                    Resolved:

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