Function SearchLunarApsis

SearchLunarApsis(startDate: FlexibleDateTime): Apsis
Finds the next perigee or apogee of the Moon.

Finds the next perigee (closest approach) or apogee (farthest remove) of the Moon that occurs after the specified date and time.
Parameters
- startDate: FlexibleDateTime
  The date and time after which to find the next perigee or apogee.
Returns Apsis