Chandra X-Ray Observatory
	(CXC)

CDA - News Item 001

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Data Analysis Links
CDA Status
  • The archive is fully functional.
Reprocessing Status
  • Reprocessing has been completed for
    • Phase I: 2005-11-13 to 2011-12-31
    • Phase II: 2000-01-30 to 2005-11-13
Current Software Releases
  • ASCDSVER: 10.1
  • CALDBVER: 4.5.9
What's New
News Item 001

Changed Sequence Numbers

In the past, when observations needed to be split (for instance, a partially completed observation had to be continued with different ACIS chips), a new ObsId with a new Sequence Number was created. We have changed that policy and currently a new ObsId with the old Sequence Number is created. In order to facilitate uniform bookkeeping, we are now changing the Sequence Numbers of past observations for these split cases so that the current policy will appear uniformly applied since the beginning of the mission. This way, different pieces of the same observation can always be tied together by their common Sequence Number.

We have posted lists of ObsIds that had their Sequence Number changed, accompanied by their parent ObsIds, separately for GTO and GO observations.

This page maintained by the Chandra Data Archive (arcops@head.cfa.harvard.edu).

Last modified: 2010-12-22

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