ROSAT Status Report #168: pcarf warning

[Michael Arida <arida@milkyway.gsfc.nasa.gov>]

Date: Mon, 22 Jun 1998 10:23:25 -0400 (EDT)
Subject: pcarf warning


XSELECT/PCARF warning
----------------------

There is a bug in the xselect extractor which causes some incorrect 
keyword values to be written to the header of ROSAT PSPC spectra 
extracted via xselect.  The CDELT1 and CDELT2 keywords are affected 
and these are used by the task PCARF. The incorrect values result in the 
following error message:

** US Rev0 data may have wrong value in PHA file. Standard value is
DELTX=2. 595021E -4. ** GT_WMAP 1.2.0   WARNING:   X pixel size of wmap is 
  1.3888890000000D- 04 degrees.  Are you sure about this? **

This message falsely indicates the spectrum was from USrev0 data, this 
is because an older (fixed) problem also used to give result in a wrong 
keyword value-and this warning was written for that case. However, the 
warning is valid in that it does indicate a keyword problem. To work 
around this problem, please invoke PCARF thus:


pcarf deltx=2.595021E-4 delty=2.595021E-4


This over-rides the bad values in the header. The extractor bug has been 
fixed and the fixed code will be available in the next release of ftools. 

If you need more detail, please email rosathelp@athena.gsfc.nasa.gov