Standard star selection

Find <UT> from kentools "ephem"
Evening: <UT> = "Eve. - 10"
Mid-night (used on half nights): <UT> = "Midpoint" minus 15m
Morning: <UT> = "Morn Std"

Identify set of standard star fields to observe in for evening/mid/morning:
  • Usually, the standards command will return 3 standard star fields; sometimes, however, only 2 fields will be returned, since a 3rd wasn't found at a suitable airmass. This is OK.

For a more detailed description see this page: Preselect standard Stars for appropriate UT