Celestral Reference Frames

[liamdiprose]

Hi Jon,

Fan of your work here who managed to land a job in the space industry.

The work you're doing here would be useful for calculating the look angle of an antenna (Bearing) to distant celestial objects located with the ICRS.

We're particularly interested in calculating the time-windows when certain distant radio sources are visible for antenna calibration. In the future we'd like to track spacecraft orbiting the Moon.

Would you be interested in adding celestial reference frames (the ICRS, Lunar, and other bodies) to sguaba?

Where does movement factor into the API? For example: Ephemerides of spacecraft.

[carlocorradini]

This could be really useful! 🙌

[smedegaard]

@liamdiprose , I have no knowledge in the field. But would lox be of use to you?

[jonhoo]

That's a super-interesting use-case, thanks for raising it!

I think one could use Sguaba for space, though my worry is that #41 (comment) would end up having even more of an effect in that setting, and thus the utility of the types would be reduced. I could be wrong though — haven't looked enough at ICRS to say for sure. One immediate question is whether there is one ICRS, or whether it defines multiple possible origins.

I'd certainly be willing to entertain merging something like this, and would be happy to review a PR to that effect, though likely won't have the cycles right now to implement it myself.

As for how movement is tracked, the only representation of it at the moment is through the Vector type, which can be annotated as a velocity (or acceleration) vector. For Ephemerides, it feels like this is mostly a Vec<Coordinate> if I'm not wrong, but maybe there is more to it that could be represented in the type system?

[liamdiprose]

Thank you for your responses everyone.

@smedegaard

• I'm not sure how I managed to overlook lox-space. I've searched the codebase but can't find anything that would convert equatorial to horizon coordinates. I'll be keeping a close eye on lox-space though. Thanks for the suggestion!

@jonhoo

• Solving Unsafe blanket impl nit #41 would be interesting for our this use case but I'm happy to express all coordinates at at certain time for now.
• Thank your for offering to support a PR. I understand this project is partially an experiment in Rust API design so we can take some extra time to think about how we add this.
• The rest of your questions are good but I can't answer them just yet. I'll be sure to document my learning and will open a PR when I feel useful 😃

[skochev84]

Forgot to put this here :)

[carlocorradini]

@skochev84 Is this a Christmas gift? 🎁😂

[skochev84]

Not exactly, it was something I played around to get familiar for an interview at Helsing but there wasn't a follow up so I post it here if someone can find it useful :)