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skyfielders / python-skyfield

Elegant astronomy for Python
MIT License
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Please add more support for working with earth satellites, i.e. satellite.itrf() #85

Closed alexamici closed 6 years ago

alexamici commented 8 years ago

I'm evaluating the use of skyfield for an application to earth observation satellites, I understand this is not a target use case at the moment, but I easily managed to extract the satellite orbital mechanics out of EarthSatellite with a modicum of code duplication, so I'd like to know if you are interested in supporting some basic form of this use case.

As an example the EarthSatellite class compute the ITRF position of the satellite for a given time object inside _compute_GCRS, but doesn't expose it in the API:

https://github.com/skyfielders/python-skyfield/blob/master/skyfield/sgp4lib.py#L67

Could you please add a EarthSatellite.itrf method that returns the rITRF and vITRF quantities already computed?

ckuethe commented 7 years ago

Also, a subsurface point method (maybe like pyephem's sublat/sublon) would be nice.

brandon-rhodes commented 7 years ago

Thanks, both are on my to-do list — I will update this issue when something is available!