Function Rotation_HOR_ECL

Rotation_HOR_ECL(time: FlexibleDateTime, observer: Observer): RotationMatrix
Calculates a rotation matrix from horizontal (HOR) to J2000 mean ecliptic (ECL).

This is one of the family of functions that returns a rotation matrix for converting from one orientation to another. Source: HOR = horizontal system. Target: ECL = ecliptic system, using equator at J2000 epoch.
Parameters
- time: FlexibleDateTime
  The date and time of the horizontal observation.
- observer: Observer
  The location of the horizontal observer.
Returns RotationMatrix
A rotation matrix that converts HOR to ECL.