About Chandra Archive Proposer Instruments & Calibration Newsletters Data Analysis HelpDesk Calibration Database NASA Archives & Centers Chandra Science Links

Skip the navigation links
Last modified: 10 October 2007

URL: http://cxc.harvard.edu/ciao3.4/bugs/reproject_events.html
Hardcopy (PDF): A4 | Letter

Bugs: reproject_events


Bugs

  1. 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. No error if matchfile is missing (06 Mar 2007)


Bugs

  1. The tool needs one good time interval per chip

    The tool needs one good time interval (GTI) per chip, otherwise the time for the other CCDs is set to zero. (Most users will never run into this issue.)

  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:

    In CIAO 3.4, you can use the DM subspace-editing capabilities to deleted 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. No error if matchfile is missing (06 Mar 2007)

    The tool does not error if the file specified in the "matchfile" parameter is missing.

Hardcopy (PDF): A4 | Letter
Last modified: 10 October 2007


The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory.
60 Garden Street, Cambridge, MA 02138 USA.    Email: cxcweb@head.cfa.harvard.edu
Smithsonian Institution, Copyright © 1998-2004. All rights reserved.