ROSAT Guest Observer Facility

Frequently Asked Questions about the ROSAT HRI

The following questions have been asked often about the ROSAT HRI.

If you have a question that you think is, or could be, a "Frequently Asked Question", please e-mail it to rosat@rosserv.gsfc.nasa. gov.

The sources for these answers have included the following: G. Hasinger (MPE), J. Schmitt (MPE), R. Fink (GSFC), D. Burrows (PSU), the GSFC GOFers (L. Angelini, K. Arnaud, G. Reichert, E. Schlegel, and J. Turner), and the SAO GOFers (L. David, F. Harnden, F. Seward, and B. Wilkes).

Select from the following topics:


  1. Does the background vary?
  2. How is the background map produced?
  3. How is the background map scaled?


  1. What is the status of the HRI spectral calibration?
  2. What UV sensitivity does the HRI have?
  3. What about temporal gain variations?


  1. How accurate are the coordinates extracted in PROS?
  2. What is the conversion from detector coordinates to sky coordinates?
  3. Just how good are the positions?
  4. What is the HRI image scale?


  1. Has the quantum efficiency of the HRI changed?
  2. Why are gaps seen in the HRI detector maps?

Housekeeping Information

  1. How can I look at the satellite "housekeeping" information?
  2. How do I know if my observation was wobbled or not?
  3. Why were the HRI observations wobbled anyway?
  4. Is the voltage turned off during SAA?
  5. What else should I notice from the hardcopy housekeeping?

Point Spread Function

  1. What does the PSF look like?


  1. How do I know whether my HRI data is affected by one of the subtle timing problems I've heard about?
  2. Should I worry about "false" periodic effects?


  1. What contributes to the vignetting?

Select another FAQ topic Select another FAQ topic Return to the ROSAT GOF Return to the ROSAT GOF

Please use the Feedback link if you have questions on ROSAT.

This file was last modified on Monday, 13-Sep-1999 15:47:42 EDT

NASA Astrophysics

  • FAQ/Comments/Feedback
  • Education Resources
  • Download Adobe Acrobat
  • A service of the Astrophysics Science Division (ASD) at NASA/ GSFC

    ROSAT Project Scientist: Dr. Robert Petre

    Responsible NASA Official: Phil Newman

    Privacy Policy and Important Notices.