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xkcd #3156: Planetary Rings (imgs.xkcd.com)
submitted 1 year ago by [B] to c/xkcd@lemmy.world
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xkcd #3156: Planetary Rings

Title text:

If you don't know where you are on Earth, the angle of satellite dishes can help constrain your latitude. If some of them are pointing straight up, you're probably near the Equator, right under the ring.

Transcript:

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Source: https://xkcd.com/3156/

explainxkcd for #3156

If you don't know where you are on Earth, the angle of satellite dishes can help constrain your latitude. If some of them are pointing straight up, you're probably near the Equator, right under the ring.
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[–] 3 points 1 year ago (1 child)

I browsed for a while and then realized, holy shit, they're moving. Is this real-time? Either way, this is awesome.

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  • [–] 10 points 1 year ago*

    Wow thanks so much!

    Yes, so I'm taking every telescope/radio/radar reading I'm allowed to redistribute and then collecting them into a time series database and fetching the most recent reading for each sat into a text file. That's the TLE download in the public API. Then I use Rust WASM to propagate those readings into positions that are synced with the viewer time. This allows us to very roughly forecast where they will be for the next couple days.

    It's cool because it's too much data to transfer over the network, so we only transfer the most recent reading and then calculate positions live in the browser.

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