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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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?
@aeva geographic lat long is relative to the an ellipsoid. 0 degrees longitude is fixed to the surface of the earth.
Equatorial is a sphere and the longitude equivalent doesn’t rotate with the earth.
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@aeva geographic lat long is relative to the an ellipsoid. 0 degrees longitude is fixed to the surface of the earth.
Equatorial is a sphere and the longitude equivalent doesn’t rotate with the earth.
@jkaniarz where I currently am stuck is how do you convert between the three when it is not the vernal equinox
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@aeva i guess that feels to me like it makes sense historically but maybe not…. anymore?
@halcy well, historically astronomy was among other things at times significantly concerned with answering the question "where the hell am I", whereas modern astronomy seems to be more split between "what is that specific bright object" and "visible spectrum is cringe"
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ok so back to the moon thing, i found another resource and i think i understand the why behind the asinine coordinate systems a little better but it also glosses over the math so it's kinda useless at the same time. i'm tempted to just make shit up and move on, but it would bother me that the function was wrong if i did that
@aeva i have copies of the explanatory supplement to the astronomical almanac in case i ever get enough of an urge to write astronomical software – both the 1960s edition and the more recent third edition that takes into account modern atomic time and general relativity and 🤯
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@aeva i have copies of the explanatory supplement to the astronomical almanac in case i ever get enough of an urge to write astronomical software – both the 1960s edition and the more recent third edition that takes into account modern atomic time and general relativity and 🤯
@fanf I just put in an order for the 2025 Astronomical Almanac - what is this about an explanatory supplement?
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ok so back to the moon thing, i found another resource and i think i understand the why behind the asinine coordinate systems a little better but it also glosses over the math so it's kinda useless at the same time. i'm tempted to just make shit up and move on, but it would bother me that the function was wrong if i did that
after a good night's sleep and reflecting on what I've learned so far, I've decided to follow the classic computer science strat: when faced with a problem you don't know how to solve, simply do something else, and pretend that is what you meant to do all along.
not only are horizontal coordinates the choice reference frame for backyard astronomers, the "altitude h" angular measurement is probably closer to the solution I wanted than my earlier framing of the problem. narf
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@fanf I just put in an order for the 2025 Astronomical Almanac - what is this about an explanatory supplement?
@aeva https://aa.usno.navy.mil/publications/exp_supp roughly speaking it explains the mathematical models used to caclculate the almanac
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@jkaniarz where I currently am stuck is how do you convert between the three when it is not the vernal equinox
@aeva If you know the position at the previous equinox, I think it’s as simple as spinning the moon around the earth (in the plane of the moons orbit) for 2*PI*t/27.3 radians, then spinning the earth for 2*PI*t radians.
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@aeva https://aa.usno.navy.mil/publications/exp_supp roughly speaking it explains the mathematical models used to caclculate the almanac
@fanf that sounds useful. looks like it is out of print though?
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after a good night's sleep and reflecting on what I've learned so far, I've decided to follow the classic computer science strat: when faced with a problem you don't know how to solve, simply do something else, and pretend that is what you meant to do all along.
not only are horizontal coordinates the choice reference frame for backyard astronomers, the "altitude h" angular measurement is probably closer to the solution I wanted than my earlier framing of the problem. narf
the math's not quite right, but i managed to get the moon more or less working
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@aeva god, on the 3rd day:
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This is the best post to read entirely out of context that I have seen in years.
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astronomy math is out of this fucking world btw like want to know where the moon is? great buckle up you're in for a few hundred years of bizarre hacks and lots of exciting questions like "wait, why are they using the julian calendar?"
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This is the best post to read entirely out of context that I have seen in years.
@CliftonR :3
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@aeva god, on the 3rd day:
@halcy :3
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astronomy math is out of this fucking world btw like want to know where the moon is? great buckle up you're in for a few hundred years of bizarre hacks and lots of exciting questions like "wait, why are they using the julian calendar?"
in a way magpie math is kinda refreshing, like imagine not throwing everything away every few years because of industry fads
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Questo post è eliminato!
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astronomy math is out of this fucking world btw like want to know where the moon is? great buckle up you're in for a few hundred years of bizarre hacks and lots of exciting questions like "wait, why are they using the julian calendar?"
@aeva I think part of it is we stopped trying to guess based on date and moved to measurements and short term extrapolation
Gli ultimi otto messaggi ricevuti dalla Federazione
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@eccosilvia parole molto sagge. Invece non solo assistiamo a eventi orrendi, ma molti fanno da amplificatore diffondendo odio su odio, spesso recitando la parte delle pecorelle buone.
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@kappazeta @GustavinoBevilacqua @thunderpussycat (il talk di @fabrixxm è il motivo per cui io non terrò un talk sul fediverso al linux day :D )
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@greenpeace a step back 200000 years, or a trip to France
(to be fair, in France said raw meat comes with plenty of vegetables, bread and/or other carbs, and some care in checking the health of the animals and how the meat has been treaded through the whole process)
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Spunti di riflessione
L'onestà intellettuale nei dibattiti pubblici è morta: ha lasciato spazio di movimento a tutto quello che è hatespeech, propaganda, tifoserie costruite nel tempo da una certa educazione culturale.
Oggi è sempre più marasma e scontro per un mondo totalmente mercificato.
I mercati ringraziano e qualcuno si sta sfregando le mani contento del fatto che il "divide et impera" ancora funziona, mentre il resto del mondo sprofonda.
Oggi viviamo nella prima guerra culturale globale.
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@NouranKhaledGh If you think your home will be under fire, please leave your home, even if you have nowhere to go. Even if there is no place in the South for you. It might be that you die if you stay.
Some families say they would rather die in their home than be displaced again and again and again. I can absolutely respect that.
Please forgive me if I say something idiotic. I can't even begin to understand how life is like in Gaza right now, and I have no right to tell you what to do.
If you want to live, it is better to live without a tent and to sleep in the streets but be in a (relatively) safe area, than to get killed while you wait for a tent.
If you absolutely must leave, please leave for the South, even if you don't have a tent yet or the money for a tent. The tent will come, but the dead can't come back to life.
Please survive. 😭💔
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I have to wait for about three months...
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@Gustodon it's what the plants crave 🌱
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Morbo di Crohn: forme più lievi e trattamenti più efficaci secondo una ricerca norvegese
https://leganerd.com/2025/09/15/morbo-di-crohn-forme-piu-lievi-e-trattamenti-piu-efficaci-secondo-una-ricerca-norvegese/
@scienza
