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ROSAT Guest Observer Facility

ROSAT Status Report: Oct 8 1997

TCDLT2 problem in converted REV0 & REV1 German Events files Now Fixed!

A problem has been detected with some ROSAT events files in the data archive. The problem is that the TCDLT2 keyword is negative in some files.

The affected files are the German Rev1 sequences, specifically, the events files which have been converted to US fits format. The German Rev 1 datasets are easily identified as they are those with directory names like wp600185, and the converted events files have names like wp600185.fits (i.e. no n00, ao1 etc trailing the sequence name, and no _bas in the filename, those are all later versions of ROSAT data, and unaffected).

The list of German Rev1 sequences in the archive can be found below along with the value of the TCDLT2 keyword in each case, a negative value indicating that the sequence was affected. About 10% of German Rev1 sequences have a correct value for TCDLT2. If you have retrieved Rev 1 German data in the past you can check the TCDLT2 keyword in the second extension of the events file to see if your data are affected. 302 observations were affected, as of Oct 8 1997.

The TCDLT2 keyword specifies how DEC changes across the field, from the reference pixel. The flip in sign means that if you make an image from the events file with software which uses this keyword, like xselect, then the resulting image has the Y-direction inverted, i.e. the DEC increases in the wrong direction. This Y-flip obviously results in an incorrect position derivation for sources in the image.

The problem has been traced back to an early version of a conversion program, which reformatted German _events.tfits files into w*_seq.fits files. As this is isolated to the events conversion program, there is no problem with other data files in the affected sequences. Most notably the "standard" SASS images in the same dataset (the _im1, _im2 etc files) are OK. The WGACAT database is also unaffected, and source positions in that database are correct, even for "affected" sequences.

The "US-formatted" REV0 & REV1 German events files which contained incorrect values of the TCDLT2 keyword have been corrected as of Oct 15 1997. Any archive users who have obtained versions of these files prior to Oct 15 1997 should retrieve the corrected versions. Note that the original (unconverted) versions of the events lists (i.e. the w*_events.tfits files) were not affected by this problem and so do not need to be replaced.
If you have any questions please email rosathelp@athena.gsfc.nasa.gov

NOTE: No HRI sequences are affected by this problem.

A list of the corrected files follows.

wp100010.fits 
wp100130.fits 
wp110016.fits 
wp110127.fits 
wp110167.fits 
wp110589.fits 
wp110602.fits 
wp130371.fits 
wp130372.fits 
wp130374.fits 
wp140296.fits 
wp140310.fits 
wp140317.fits 
wp140318.fits 
wp140319.fits 
wp140321.fits 
wp140322.fits 
wp140326.fits 
wp141856.fits 
wp141858.fits 
wp141867.fits 
wp141878.fits 
wp141879.fits 
wp141880.fits 
wp141889.fits 
wp150044.fits 
wp160030.fits 
wp160085.fits 
wp180001.fits 
wp180002.fits 
wp200156.fits 
wp200157.fits 
wp200158.fits 
wp200159.fits 
wp200160.fits 
wp200161.fits 
wp200162.fits 
wp200175.fits 
wp200196.fits 
wp200198.fits 
wp200199.fits 
wp200200.fits 
wp200209.fits 
wp200211.fits 
wp200216.fits 
wp200220.fits 
wp200228.fits 
wp200235.fits 
wp200236.fits 
wp200237.fits 
wp200238.fits 
wp200241.fits 
wp200411.fits 
wp200412.fits 
wp200423.fits 
wp200433.fits 
wp200437.fits 
wp200438.fits 
wp200452.fits 
wp200604.fits 
wp200612.fits 
wp200617.fits 
wp200618.fits 
wp200619.fits 
wp200622.fits 
wp200636.fits 
wp200659.fits 
wp200701.fits 
wp200703.fits 
wp200715.fits 
wp200851.fits 
wp200853.fits 
wp200856.fits 
wp200861.fits 
wp200862.fits 
wp200864.fits 
wp200866.fits 
wp200867.fits 
wp200869.fits 
wp200872.fits 
wp200888.fits 
wp201077.fits 
wp201078.fits 
wp201079.fits 
wp201082.fits 
wp201092.fits 
wp201107.fits 
wp201113.fits 
wp201114.fits 
wp201119.fits 
wp201122.fits 
wp201123.fits 
wp201139.fits 
wp201144.fits 
wp201145.fits 
wp201177.fits 
wp201179.fits 
wp201182.fits 
wp201183.fits 
wp201228.fits 
wp201234.fits 
wp201241.fits 
wp201248.fits 
wp201249.fits 
wp201262.fits 
wp201263.fits 
wp201267.fits 
wp201268.fits 
wp201272.fits 
wp201279.fits 
wp201288.fits 
wp201292.fits 
wp201294.fits 
wp201295.fits 
wp201296.fits 
wp201305.fits 
wp201311.fits 
wp201312.fits 
wp201313.fits 
wp201325.fits 
wp201368.fits 
wp201371.fits 
wp300033.fits 
wp300035.fits 
wp300036.fits 
wp300038.fits 
wp300040.fits 
wp300041.fits 
wp300068.fits 
wp300164.fits 
wp300176.fits 
wp300217.fits 
wp300219.fits 
wp300267.fits 
wp300292.fits 
wp300293.fits 
wp300294.fits 
wp400039.fits 
wp400041.fits 
wp400054.fits 
wp400178.fits 
wp400312.fits 
wp400322.fits 
wp400323.fits 
wp400329.fits 
wp500041.fits 
wp500043.fits 
wp500045.fits 
wp500048.fits 
wp500052.fits 
wp500056.fits 
wp500057.fits 
wp500058.fits 
wp500062.fits 
wp500122.fits 
wp500193.fits 
wp500201.fits 
wp600058.fits 
wp600066.fits 
wp600079.fits 
wp600100.fits 
wp600185.fits 
wp600188.fits 
wp600195.fits 
wp600196.fits 
wp600204.fits 
wp600296.fits 
wp600297.fits 
wp600298.fits 
wp600299.fits 
wp600300.fits 
wp600301.fits 
wp600303.fits 
wp600305.fits 
wp600306.fits 
wp600308.fits 
wp600309.fits 
wp600311.fits 
wp600312.fits 
wp600316.fits 
wp600317.fits 
wp600318.fits 
wp600319.fits 
wp600321.fits 
wp600322.fits 
wp600323.fits 
wp600327.fits 
wp600329.fits 
wp600330.fits 
wp600334.fits 
wp600335.fits 
wp600336.fits 
wp600338.fits 
wp600339.fits 
wp600340.fits 
wp600341.fits 
wp600342.fits 
wp600346.fits 
wp600354.fits 
wp600355.fits 
wp600356.fits 
wp600358.fits 
wp600359.fits 
wp600360.fits 
wp600361.fits 
wp600362.fits 
wp600366.fits 
wp600371.fits 
wp600374.fits 
wp600375.fits 
wp600378.fits 
wp600415.fits 
wp600417.fits 
wp600419.fits 
wp600437.fits 
wp600448.fits 
wp600462.fits 
wp700138.fits 
wp700145.fits 
wp700151.fits 
wp700164.fits 
wp700170.fits 
wp700173.fits 
wp700180.fits 
wp700186.fits 
wp700201.fits 
wp700216.fits 
wp700226.fits 
wp700227.fits 
wp700229.fits 
wp700262.fits 
wp700468.fits 
wp700496.fits 
wp700498.fits 
wp700508.fits 
wp700516.fits 
wp700528.fits 
wp700535.fits 
wp700536.fits 
wp700538.fits 
wp700552.fits 
wp700553.fits 
wp700557.fits 
wp700577.fits 
wp701034.fits 
wp701038.fits 
wp701045.fits 
wp701048.fits 
wp701050.fits 
wp701055.fits 
wp701063.fits 
wp701068.fits 
wp701072.fits 
wp701087.fits 
wp701093.fits 
wp701129.fits 
wp701139.fits 
wp701140.fits 
wp701144.fits 
wp701150.fits 
wp701153.fits 
wp701174.fits 
wp701179.fits 
wp701195.fits 
wp701200.fits 
wp701207.fits 
wp701213.fits 
wp701217.fits 
wp701219.fits 
wp701233.fits 
wp701234.fits 
wp800073.fits 
wp800096.fits 
wp800162.fits 
wp800174.fits 
wp800184.fits 
wp800333.fits 
wp800339.fits 
wp800340.fits 
wp800341.fits 
wp800345.fits 
wp800353.fits 
wp800365.fits 
wp800369.fits 
wp800385.fits 
wp800390.fits 
wp800393.fits 
wp800401.fits 
wp800403.fits 
wp800411.fits 
wp800415.fits 
wp800416.fits 
wp900026.fits 
wp900143.fits 
wp900201.fits 
wp900212.fits 
wp900220.fits 
wp900222.fits 
wp900223.fits 
wp900228.fits 
wp900233.fits 
wp900425.fits


Curator: Michael Arida (SP Sys); arida@milkyway.gsfc.nasa.gov
HEASARC Guest Observer Facility
Please use the Feedback link if you have questions on ROSAT.

This file was last modified on Monday, 13-Sep-1999 15:47:28 EDT

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