Chandra X-Ray Observatory

CDA - Proprietary Data

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: 10.5.2
    • CALDBVER: 4.7.3
    What's New
    • Take our Survey
      We would like to ask you a few questions about the interfaces offered by the Chandra Data Archive to search and retrieve Chandra data. The questionnaire should not take more than 5 minutes. Thank you!
    • Past Notices
Handling of Proprietary Chandra Data

PI and CoI, Observer

Associated with each proposal is a Principal Investigator (PI) and, optionally, a Co-Investigator/Observer (CoI/O). If there is no CoI/O, the PI is the Observer.

  • The Observer is the person who is responsible for the observation parameters and with whom User Support works to ensure a correct observation specification.
  • E-mail notification of the data being ready for download is sent to the PI and the CoI/O. If hard medium distribution is requested, the medium is sent to the PI.
  • Change of CoI/O: a request for changing the CoI/O has to come from the PI by e-mail and be directed to the Director's Office at: . (Note that a CoI/O can only be assigned per proposal, not on the basis of an individual ObsId.)

Procedures and Policies

Proprietary data are distributed through ChaSeR and on physical media. Data products generated by Automated Processing first have to go through Verification and Validation. The Principal Investigator and the Co-Investigator/Observer will then be notified that the data are available through ChaSeR; at the same time a copy is made on physical medium, if requested, that is mailed to the PI only. Products generated by Custom Processing also go through V&V but are only distributed through the ftp site. In all cases the tar file contains a Standard Data Distribution.

Access to proprietary data (i.e., the proprietary products associated with proprietary observations) is restricted to two accounts: a PI account (that provides access to all proprietary observations of the PI) and a proposal account (that provides access to all proprietary data associated with a particular proposal and that the PI may want to share with collaborators). The Data Distribution e-mail notification contains a reminder about the latter account.

The staging procedures for data retrieved from the CDA include the use of hidden directories to protect the potentially proprietary nature of the data. This mechanism is effective but requires the user to enter the full path or URL, rather than meandering through the ftp directory structure. The only situation where this might cause a problem is when users employ Safari as their web browser; we recommend switching web browsers in that case.

This page maintained by the Chandra Data Archive (

Last modified: 2010-12-22

Smithsonian Institute Smithsonian Institute

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email: Smithsonian Institution, Copyright © 1998-2016. All rights reserved.