Help with TLE to azimuth and elevation function

[Marijn]

Hello all,

For a fun project (my smart lighting), I am looking for a function which outputs the azimuth and elevation along with the associated timestamps of an earth-orbiting object at a given location on earth.

Much like the info on https://www.heavens-above.com/. Unfortunately, they never published an API. So I like to try this myself now. Also, I want it to accept TLE's and not some catalog id.

Publishing the API is easy. But I need some help with the math. Anybody who can help me work this out or can point me to some resource to start from?

Thanks!

 

[boogabooga]

Just poke around this website:

https://celestrak.com/

It should be a lot of help.

 

[dgatsoulis]

This should help (requires python and pyephem -3.7b)
tle2azel

 

[Marijn]

Thanks, I'll have a look.

 

[kuddel]

If your can "read MATLAB", this repo has some code...
or if you prefer JavaScript this repo has lots of functionality.

 

[Marijn]

Thanks. The plan is to deploy the code in a Google Apps Script environment. That's serverside Javascript with some extra restrictions. I'll have a look at it.

 

[kuddel]

I somehow guessed that you like to have some code (or math) to look at.:yes:

Calculating the azimuth and elevation is the easiest part by the way. But as TLEs are usually snapshots "from the past", propagating the actual satellite position to a later time (now) is the heavy lifting part...

BTW: In case you've missed the obvious source, Doc\Technotes\dynamics.pdf has some details on that topic.