[AstroPy] Question on astropy.coordinates internals

[Hervé Aussel]

	Hello, 

I am working on a package to handle spacecrafts attitudes in python, and I would like to build on the astropy.coordinates package, especially to handle transformations between reference frames. I have a few questions regarding the internals of the package. 

- What is the correct way to check that an input is a bona fide reference frame ? Playing around, I have come with this:
import astropy.coordinates as coord
isinstance(my_input_frame, coord.baseframe.FrameMeta)

- Is there a way to access the directly the coodinate tranformation matrix ? So far, I use the transformation on each of the cartesian unit vector to build the rotation matrix, but this is a bit clunky...

Thanks for your help, 

Cheers, 

Hervé



-----------------------------------------------------------------------------------------
Hervé Aussel

EC SPV Lead

AIM Paris-Saclay                                  phone: (+33) 01 69 08 95 79
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