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Last modified: 1 October 2010

URL: http://cxc-newtest.cfa.harvard.edu/ciao4.2/bugs/reproject_events.html

Bugs: reproject_events


Bugs

  1. All events are lost after reprojection /
    The tool needs one good time interval per chip

  2. Running dmcoords on reprojected event files will result in incorrect chip locations.

  3. Running the tool on a spatially filtered file does not update the "region" subspace. (23 Mar 2007)

  4. If the input file is missing, the tool SegVs. (18 May 2010)


Bugs

  1. All events are lost after reprojection /
    The tool needs one good time interval per chip

    If the subspaces of the two files don't match - e.g. observation A was taken with S5 and that chip wasn't used in observation B - all the events are dropped from the output file (not just those on the chip that's missing).

    The bug may also be described as: the tool needs one good time interval (GTI) per chip, otherwise the time for the other CCDs is set to zero.

  2. Running dmcoords on reprojected event files will result in incorrect chip locations.

    The *NOM values from the original (unprojected) input file need to be overridden.

  3. Running the tool on a spatially filtered file does not update the "region" subspace. (23 Mar 2007)

    The spatial filter is recorded in the file subspace, but it is not reprojected when reproject_events is run. When reproject_events changes the sky tangent point, the region in the subspace is "shifted" in the reference frame.

    In many cases, users run into this problem when they do the following order of events:

    1. Use a spatial filter to select certain ACIS chips (e.g. just the ACIS-I array)
    2. Run reproject_events on the filtered event file
    3. Attempt to extract spectra with a source list.

    The final output has zero exposure and/or empty GTIs because the source list and the initial, unshifted region filter (stored in the file subspace) don't intersect.

    Workaround:

    Use the DM subspace-editing capabilities to delete the filter specification written in the file subspace:

    unix% dmcopy "reprojected_file.fits[subspace -sky]" reprojected_file_fix.fits
    

    An alternative is to run reproject_events before applying any spatial filtering.

  4. If the input file is missing, the tool SegVs. (18 May 2010)


Last modified: 1 October 2010