Glossary

• detx raw detector x position ( i.e. , before rotation and aspect correction)
• dety raw detector y position ( i.e. , before rotation and aspect correction)
• pha pulse height analyzer channel. Accepted values 0-15 ( Einstein IPC), 1--256 (ROSAT PSPC)
• pi pulse invariant bin (energy). Accepted values 0-15 ( Einstein IPC), 1--256 (ROSAT PSPC) and 1--34 (ROSAT PSPC, SASS output).
• region a selected region of the image of various forms. Used to select only a portion of the image, within which the current operations should be applied.
• time photon arrival time in sec.
  • ¸ from Jan. 0, 1978, for Einstein data
  • Spacecraft clock time (can be converted to UT) from 21:06:50.2 June 1, 1990 for ROSAT data
• x - y ¸ pixel position in sky pixel ( i.e. , after aspect correction). Values start from 1 in the lower left corner