Configuring mounts in Orekit

Hi Orekit Forum,

I am new to Orekit but learning quickly.

My question pertains to the types of mounts which we can model in Orekit. I was wondering whether Orekit supports the following mounts (not looking to examine code yet - a little later) or how one mount convert using the API to these mounts:

  • An ‘altitude-azimuth’ or ‘altitude-elevantion’ mount (this I believe it does
  • An ‘equitorial’ mount
  • Dobsonian mounts
  • German equitorial mounts

All feedback is appreciated.


Hi @quickyme, welcome

The TopocentricFrame class, which can be used to represent a coordinate system at some ground point, supports natively directions in azimuth/elevation, using the classical convention of azimuth being 0 at North and counting positively towards East (i.e. 90° at East, 180° at South, 270° at West).
In order to support other angles for referencing a direction, you can use the various way to create Rotation objects provided by the Hipparchus library. You can typically combine two rotations to represent any mount you want. This can be tricky due to angles conventions and rotation ordering. Hipparchus supports both frame convention and vector operator convention (which basically correspond to changing the sign of the angle), but in most cases, you end up trying different signs and composition order before finally getting it right.