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  1. Data Management
  2. DM-20841

Investigate reports of incorrect meas_mosaic WCSs after rotation by 90deg

    Details

    • Type: Story
    • Status: Done
    • Resolution: Done
    • Fix Version/s: None
    • Component/s: afw, meas_astrom
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      Description

      Hisanori Furusawa and Sogo Mineo report that most of the WCSs produced by meas_mosaic in hscPipe 6.x (all of those that correspond to sensors with rotations relative to the focal plane) are incorrect - the SIP coefficients are dropped after rotation.  This is seen both in the headers and in the binary table.

      After a quick look at the code, I suspect this is only superficial, but still confusing: we rotate a WCS by prepending its mappings with a rotation using AST, which yields a WCS that cannot be represented as TAN-SIP without loss of precision.

      First piece of this ticket is to check that hypothesis.  The second (assuming the hypothesis holds) is to come up with a way to reduce that confusion.

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            • Assignee:
              jbosch Jim Bosch
              Reporter:
              jbosch Jim Bosch
              Reviewers:
              Jim Bosch
              Watchers:
              Jim Bosch, John Parejko, Paul Price, Tim Jenness
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                Updated:
                Resolved:

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