Reference frames (old) - poliastro/poliastro GitHub Wiki

Two options that I know of: astropy.coordinates and sympy.mechanics.vector.

astropy.coordinates

http://docs.astropy.org/en/v1.2.1/coordinates/index.html

Pros

• Defines many useful astronomical frames and the transformations between them
• Compatible with basic Python and NumPy types

Cons

• Does not support velocities https://github.com/astropy/astropy/issues/4344

sympy.mechanics.vector

http://docs.sympy.org/1.0/modules/physics/vector/index.html

Pros

• Supports kinematics
• Supports composition
• Simple implementation

Cons

• Closely tied to SymPy