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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Quanto ha fatto caldo quest’estate in cinque grafici
@politica
https://pagellapolitica.it/articoli/caldo-estate-2025-grafici
È stata la quinta più calda dal 1950, con aumenti delle temperature in tutte le regioni italiane e in gran parte d’Europa
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Wordle 1,549 3/6*
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Glasgow, 1980.
Photo by Raymond Depardon
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I like to follow interesting people. Interesting to me. For what they do, or think, or the way they are. I have a lot of interests to be honest. This include some people with different ideas or preferences. Sometimes I am just curious. Well, it's all folks.
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I don't think in Italy you can have vaccines shots without a doctor somewhere in the middle but maybe I should check...
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@Antonio1959 aah beh, sii beh... 🙂
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Da oggi le domande, ma sappiate che:
"Solitamente le domande accolte sono molte di meno di quelle presentate: nel 2024 hanno ricevuto il bonus 3.325 persone, lo 0,8 per cento delle oltre 400mila che erano state richieste. Secondo le stime dell’INPS, quest’anno i fondi basteranno al massimo a dare il bonus a 6.300 persone."
https://www.ilpost.it/2025/09/14/bonus-psicologo/?homepagePosition=13
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Beh con i prezzi che vedo a Firenze devo dire che non mi sembra neanche questa grande richiesta.
RE: flipboard.com/users/WiredItali…
