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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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 believe all our physical models diverge from reality on a long enough timescale. even quantum mechanics. every model is lossy compression / fitting of reality that we extrapolate from, starting at the time that the underlying measurements were taken.
best thing i can think of is measure exact position of celestial bodies, then run a sufficiently detailed n-body sim with best guesses for all state we can not measure, starting at that point. and then restart every year.
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@aeva is this one of those things where the approximate solution that drifts from reality by 0.0004% every year is like 3 lines and the more correct one is 5 pages of dense research and no one who writes about it is concerned with the idea that a reader may be a beginner and not know the difference
@halcy there's no closed form solution at all and from what i can tell the good solutions need to be rejiggered every few decades to stay accurate
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@halcy there's no closed form solution at all and from what i can tell the good solutions need to be rejiggered every few decades to stay accurate
@halcy the real problem here is that academic astronomy best practice is to tie everything into spherical coordinates on the firmament so they can factor out the earth enough that you can pretend it is a fixed vantage point that doesn't spin, and if god forbid you do need to tie an observation to geographic coordinates for some reason i guess you just burn an undergrad on it and not sully yourself with the indignity
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@halcy the real problem here is that academic astronomy best practice is to tie everything into spherical coordinates on the firmament so they can factor out the earth enough that you can pretend it is a fixed vantage point that doesn't spin, and if god forbid you do need to tie an observation to geographic coordinates for some reason i guess you just burn an undergrad on it and not sully yourself with the indignity
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@halcy the real problem here is that academic astronomy best practice is to tie everything into spherical coordinates on the firmament so they can factor out the earth enough that you can pretend it is a fixed vantage point that doesn't spin, and if god forbid you do need to tie an observation to geographic coordinates for some reason i guess you just burn an undergrad on it and not sully yourself with the indignity
@halcy i've got a feeling that this is what a self taught programmer feels when they try to work out how to sort stuff faster and everything they find is either programmers telling eachother to just use a library or academic formalist nonsense
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@halcy the real problem here is that academic astronomy best practice is to tie everything into spherical coordinates on the firmament so they can factor out the earth enough that you can pretend it is a fixed vantage point that doesn't spin, and if god forbid you do need to tie an observation to geographic coordinates for some reason i guess you just burn an undergrad on it and not sully yourself with the indignity
@aeva i guess that feels to me like it makes sense historically but maybe not…. anymore?
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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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the math's not quite right, but i managed to get the moon more or less working
@aeva god, on the 3rd day:
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the math's not quite right, but i managed to get the moon more or less working
This is the best post to read entirely out of context that I have seen in years.
Gli ultimi otto messaggi ricevuti dalla Federazione
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@mariosiniscalchi Oltre a Stefano Nazzi, in quel podcast parla una giornalista de Il Post che è nata e cresciuta a Metropoli in una famiglia di dipendenti ENI.
Sin dai tempi di Olivetti, è difficile separare l’dea di un avanzatissimo welfare aziendale dal ghetto dorato; alcune cose anche se fatte con le migliori intenzioni finivano per dare un approccio totalizzate all’azienda.
Non si lavorava per, si viveva in, h24.
Certo l’Italia usciva da una guerra, quelli erano paradisi.
Fango? Bah.
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@valhalla @sabrinaweb71 @phabrizio chi lo sa?
Magari il mio è un rant di chi prima, non da ricco ma da privilegiato in un mondo di schiavi, si prendeva un lusso potendoselo permettere
Ma non sono d'accordo con quest'ottica: perché è come un dire facciamo la rivoluzione ora senza un vago programma (deresponsalizzante), altrimenti la rivoluzione non si farà, quindi rassegnamoci e andiamo avanti (resa totale)
Preferisco constatare che non è mai stato un lusso e le cose vanno peggio per tutti
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@sabrinaweb71 @filobus @phabrizio (poi ci sarebbe da dire che in un paese civile tutti, anche quelli che lavorano facendo caffé in un bar, dovrebbero potersi permettere di spendere magari 5 euro (compresa la brioche) per un piccolo lusso con una frequenza magari non di tutti i giorni, ma neanche solo una volta all'anno o simili. ma quello è un discorso ben più ampio)
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Secondo me ci sono 2 cose da considerare:
- probabilmente, come tanti, aveva aspetti positivi (molti vantaggi per i dipendenti, molto determinato con politica anche internazionale), che negativi (nessun rispetto per l'ambiente e sotterfugi politici)
- va inquadrato nel suo tempo. Non si può giudicare con sensibilità di oggi. Va confrontato coi personaggi e con le pratiche dell'epoca.Penso sia un personaggio positivo, ma per certi versi aveva uno stile politico alla Elon Musk, esternamente non guardava in faccia a nessuno, nel bene e nel male
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@simona merciiiii Simona ! Je vais voir si j'arrive à m'organizer
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@sabrinaweb71 @GustavinoBevilacqua @rastinza @phabrizio
/me va a prendere una tazza da té del servizio bello e la tiene in mano in modo elegante
/me assume il suo atteggiamento più altezzoso
l'ufficio con il microonde e senza bollitore è un chiaro segno di mancanza di civiltà.
(sto bluffando. quelle tazze da té non le usiamo mai. alla mattina bevo il té da muratori irlandesi in una mug grande e non ci metto neanche né zucchero né latte :D )
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It's #ManpageMonday so we're sharing snippets from the man pages. To read more, see `man bastille-clone`.
EXAMPLES
Clone myjail to newjail:
> bastille clone myjail newjail 10.23.3.4/24Clone myjail to newjail with DHCP (VNET only):
> bastille clone myjail newjail DHCPClone myjail to newjail while running, with debug mode:
> bastille clone -xl myjail newjail 10.23.3.4/24
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As today, Russia's war in Ukraine has lasted longer than Russia's WWII
