i nerd sniped myself tonight and i imagine the NSA operative who is assigned to me is very confused by the increasingly erratic and frustrated google searches for HOW DO I CALCULATE THE MOON WHERE IS THE MOON
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@aeva @demofox @dotstdy @jon_valdes There's lots of versions of CPU sin/cos as well. The fastest is basically identical to the GPU one - about 12 bits of precision, IIRC. Then they do iteration internally if you want higher precision. There's no magic - everything costs!
As you noticed, sometimes it's better not to call sin-vs-cos, because you're not guaranteed to get magnitude 1.0. In those cases it's better to get sin and derive the other by doing sqrt(1-sin^2).
@aeva @demofox @dotstdy @jon_valdes Also, if you care about precision at all, do range reduction yourself beforehand. Otherwise you have no idea how it's being done internally.
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@aeva @demofox @dotstdy @jon_valdes Also, if you care about precision at all, do range reduction yourself beforehand. Otherwise you have no idea how it's being done internally.
@TomF @demofox @dotstdy @jon_valdes I already do the range reduction. I learned that the hard way once upon a time XD
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wikipedia: even the ancient babylonians knew how to use math to figure out what the moon is up to
me: great how do i do that
wikipedia: 😏
today's extremely basic astronomy question that i'm finding surprisingly difficult to find an answer to: are geographic coordinates and equatorial coordinates the same coordinate system except one is for looking up and the other is for looking down, or is there some essential conversion step needed to correlate them?
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today's extremely basic astronomy question that i'm finding surprisingly difficult to find an answer to: are geographic coordinates and equatorial coordinates the same coordinate system except one is for looking up and the other is for looking down, or is there some essential conversion step needed to correlate them?
i feel like i'm so close to getting this working. i found a simple implementation of ELP2000-85 that gives the approximate ecliptic coordinates and distance of the moon for a given julian century, i found math for translating between ecliptic and equatorial coordinates, and the math for working with the julian calendar looks easy enough, so i just need to figure out the missing conversions and decide on an internal time keeping standard
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i feel like i'm so close to getting this working. i found a simple implementation of ELP2000-85 that gives the approximate ecliptic coordinates and distance of the moon for a given julian century, i found math for translating between ecliptic and equatorial coordinates, and the math for working with the julian calendar looks easy enough, so i just need to figure out the missing conversions and decide on an internal time keeping standard
i think astronomy would be a lot simpler if ancient peoples didn't get so hung up on conceptualizing celestial bodies as spheres and simply invented linear algebra first
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i think astronomy would be a lot simpler if ancient peoples didn't get so hung up on conceptualizing celestial bodies as spheres and simply invented linear algebra first
@aeva On cosmology sequence breaks: Terence Tao noted that an ancient Greek heliocentrist got his arguments shot down because others said, hey, if the earth moves so much yet the stars seem to stay still, the universe would have to be *thousands* of times bigger than anyone figures it is. And how would you know, back then, it was way *more* than thousands of times bigger?
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i think astronomy would be a lot simpler if ancient peoples didn't get so hung up on conceptualizing celestial bodies as spheres and simply invented linear algebra first
@aeva a lot of things would be simpler if cults based on "perfect" shapes hadn't done all the [gestures] that they did
divine geometry is a helluva drug
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@aeva On cosmology sequence breaks: Terence Tao noted that an ancient Greek heliocentrist got his arguments shot down because others said, hey, if the earth moves so much yet the stars seem to stay still, the universe would have to be *thousands* of times bigger than anyone figures it is. And how would you know, back then, it was way *more* than thousands of times bigger?
@rf they were so close lol
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@aeva a lot of things would be simpler if cults based on "perfect" shapes hadn't done all the [gestures] that they did
divine geometry is a helluva drug
@aeva on the other hand getting extremely horny for triangles is both funny and kinda relatable, so
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@aeva a lot of things would be simpler if cults based on "perfect" shapes hadn't done all the [gestures] that they did
divine geometry is a helluva drug
@SnoopJ we're still using spherical trig in astronomy today despite earth being an ellipsoid
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@aeva on the other hand getting extremely horny for triangles is both funny and kinda relatable, so
@SnoopJ mood
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@SnoopJ we're still using spherical trig in astronomy today despite earth being an ellipsoid
@aeva well, yea, because astronomy doesn't really give a shit what shape the earth is anyway
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@aeva well, yea, because astronomy doesn't really give a shit what shape the earth is anyway
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I just want to calculate the current direction of tidal force from the observer's earth-relative position in space and time is that so wrong
@aeva oh what a fun one
have you encountered the thing where every computation in astronomy is coordinate conversion
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@aeva oh what a fun one
have you encountered the thing where every computation in astronomy is coordinate conversion
@ireneista yes
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@ireneista yes
@aeva "fun", isn't it
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i think astronomy would be a lot simpler if ancient peoples didn't get so hung up on conceptualizing celestial bodies as spheres and simply invented linear algebra first
i just want to calculate my current ecliptic coordinates from my current geographic coordinates is that so wrong
Gli ultimi otto messaggi ricevuti dalla Federazione
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Perché il #trasportoPubblico in Italia non migliora?
Una risposta ariiva da questo articolo di @ambientenonsolo.bsky.social che evidenzia come nel corso degli ultimi 30 anni i finanziamenti hanno cambiato nome tante volte, ma sono sempre diminuiti in termini di spesa reale.
Le conseguenze sulla qualità del servizio sono sotto gli occhi di tutti.
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@liw I don't know, to me they feel like perfectly reasonable computers controlled by hostile alien creatures who take some effort to make them really shitty to use
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Puntata del 13/9/2025
@anarchia
Puntata del 13/9/2025 Mattia 14/09/2025 L’accanimento del governo Meloni sui più vulnerabili è ormai cosa nota e non certo nascosta. L’idea di risolvere le problematiche delle carceri italiane e la drammaticità dei suicidi in cella costruendo nuove carceri, fino all’abominevole...Vedi l'articolo
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@matz il divanetto su cui svenire elegantemente ce l'hai?
qualcuno che si premuri di portarti i sali se ti stendi sul divanetto per svenire ce l'hai?
approfittane! :D
(seriamente: immagino che se la cosa va avanti ti aggiusteranno le dosi della terapia, e andrà a posto)
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@hikingdude aw 🥲 hope we have a chance to meet one day. And yes it’s such a lovely area here… heading back to Paris today though
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@aeva @demofox @dotstdy
Yeah, I should have mentioned I'm not 100% sure of the quality of that SW sin implementation. I grabbed it from the internets and hoped the kind stranger that wrote it knew what they were doing.I was more interested in the GPU differences at the time, and this impl was good enough to show those clearly
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@Spiggitzfan in Italy it's a common say that "Mussolini did good things too".
It's always been understood as a way for fascists to sanitize his image.
Famously, Berlusconi replied this to Clinton on a visit, and Roberto Benigni joked about it: for fuck's sake, of course he did, even Hitler and Stalin must have had some road built. Even Florence's Monster (a serial killer) must have said "good morning" to someone at some point!(in Italian
https://youtu.be/_yWTvhv2w4c )
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Caparezza: giovedÌ 13 agosto 2026 concerto alla festa di radio onda d’urto
@anarchia
Caparezza torna alla Festa di Radio Onda d’Urto, l’edizione numero 34, in calendario nell’agosto 2026, come sempre all’area feste di via Serenissima a Brescia. La data, già annunciata dall’artista, è quella di giovedì 13 agosto 2026, nell’ambito dell’”Orbit Orbit Tour”,...
