8.4.2 High-Dispersion

  The TTDC module writes the following information to the HISTORY portion of the high-dispersion image label:

• THDA used for correcting dispersion constants,
• date of observation used for correcting dispersion constants,
• zeropoint correction in Ångstroms for each order,
• spacecraft velocity vector,
• Earth velocity vector,
• net (spacecraft + Earth) correction vector to heliocentric velocity, and
• heliocentric velocity correction in kilometers per second.