4.1.2 SXT_CEN

The routine SXT_CEN should be used by all routines that wish to determine the S/C pointing. The function will return the pointing in SXT full resolution pixels for the set of times passed. The following logic is used if no switches are used

• Check to see if the ATT database files are available. The processed pointing value has already been calculated and is saved in those files.
• If the ATT step above fails, check to see if the ATR database file exist (or old PNT files). If they do, call GET_SUNCENTER to reduce the raw IRU and HXA data stored in the PNT files and return the actual S/C pointing.
• If the ATT and PNT steps fail, then read the commanded S/C file. This result gives the coarse pointing and will not correct for S/C drift.

Some sample calls are:
IDL> cen = sxt_cen(times)

IDL> cen = sxt_cen(roadmap, /cmd)

IDL> cen = sxt_cen(index, roll=roll)
The S/C roll value can optionally be returned with the keyword parameter roll. The roll values are only valid if the ATT database is available. If the /cmd option is used, it will use the commanded S/C data file which is much faster than reading the ATT database files. See the discussion on page for more details on the ATT database.