UmbralRaptor changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> egg|nomz|egg: generally if your eyes are dewing over, that's not the weather. | <ferram4> I shall beat my problems to death with an engineer. | We can haz pdf
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<whitequark> egg|cell|egg: i think it may have been done?
<whitequark> let's check that first
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<UmbralRaptop> !8 is asking scientists for more details on these architectures going to be like herding cats?
<galois> UmbralRaptop: no
* UmbralRaptop meows in annoyance at galois
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<B787_300> which architectures?
<SilverFox> UmbralRaptop, scishow just put out a video about TMT Thirty Metre Telescope
<kmath> YouTube - TMT: The World’s Most Controversial Telescope
<UmbralRaptop> B787_300: instrument efficiency for all of them, telescope size for two of them, and locations for several
<UmbralRaptop> One is "3-meter class" which I could maliciously interpret as anything between like 2.3 m and 3.5 m
<B787_300> instrumnet effciency as in QE curves or?
<B787_300> encirc energy or spot size or what
<UmbralRaptop> Overall system throughput (averaged over all wavelengths)
<UmbralRaptop> (Those diffusers and scramblers make numbers along the lines of 1-10% possible)
<B787_300> scramblers?
<UmbralRaptop> Fiber scrambles for making light less coherent so you don't get weird interference patterns
<UmbralRaptop> Sometimes motorized systems oscillating the fibers in various ways
<B787_300> oh right because you are doing stuff with spectroscopes
<B787_300> ^spectrometers
<UmbralRaptop> But really you want something less regular. like a student waving around the fiber
<UmbralRaptop> "4 / 6 identical 6m class telescopes. Bare minimum is 4x6m. Reality check: 2x6m in North, 4x4m in South." ← spot the problems
<B787_300> 4m only in the south
<B787_300> is this from a paper?
<UmbralRaptop> the spreadsheet
<B787_300> and that is 6 telescopes in the reality check
<B787_300> which doesnt match the bare min
<UmbralRaptop> Actually, two of the four 6 m class telescopes on earth are in the south (Magellan Telescopes at La Silla)
<B787_300> (i was saying you want 4x4m in the south, but your first part is 4 or 6 6m class, 4m is much smaller than 6 m)
<UmbralRaptop> The problem with 4 telescopes in the south for longitudinal coverage is: south america, africa, australia, and ???
<B787_300> an island like the galapagos?
<UmbralRaptop> (In the north you can do Hawaii, Arizona, Spain, and eastern Europe / Asia)
<B787_300> although that is close to SA as it is
<UmbralRaptop> Galapagos are probably too close to Chile. New Zealand maybe?
<B787_300> could wait a couple centuries and hope the Hawaii hotspot moves much farther and faster southward?
<UmbralRaptop> Hah
<B787_300> how far south of the equator would they need to be?
<B787_300> and what are you assuming the min elevation would be?
<UmbralRaptop> Probably ~20-40?
<B787_300> is the 20-40 for both questions?
<UmbralRaptop> A; elevation is based on actual sites, so only like 1 km for Siding Spring and Sutherland
<B787_300> sounds like you should buy an old oil rig and remoor it in the S Pacific and put a telescope on it
<B787_300> although at that point you might reach cost parity with a spacebased telescope
<UmbralRaptop> I… should suggest that and see what happens
<UmbralRaptop> semi-related: "2x 10-m (N & S)" <-- this means Keck and pretending a copy is made in the south. HET, SALT, and GTC are out
<B787_300> GTC is Grand Telescope Carnaias? (the scope in the Canaries)
<B787_300> also BTA for one of the north hemisphere ones?
<UmbralRaptop> \yeah, but I may have underestimated it
<UmbralRaptop> And I never found weather info for BTA's site
<B787_300> UmbralRaptop: slide 3? ПогодаКоличество часов
<B787_300> might need to get egg to translate some of it
<UmbralRaptop> hrm
<B787_300> also has surface errors of the main mirror in there
<B787_300> this thing still makes no sense to me... https://en.wikipedia.org/wiki/Large_Zenith_Telescope ... oh lets spin a pan of liquid mercury to make a mirror, but we can only look straight up at whatever is directly over the site
<galois> [WIKIPEDIA] Large Zenith Telescope | "The Large Zenith Telescope (LZT) was a 6.0-meter diameter liquid mirror telescope located in the University of British Columbia's Malcolm Knapp Research Forest, about 70 km (43 mi) east of Vancouver, British Columbia, Canada. (North of Maple Ridge.) It was one of the largest optical telescopes in the..."
<UmbralRaptop> ¯\_(ツ)_/¯
<UmbralRaptop> I guess I could bug colorlessfermion about the legend and axes on those graphs
<B787_300> or hunt and peck at a russian keyboard to put it into G Translate
<UmbralRaptop> Apparently the bars are observers, operators, and theoretical, respectively
* UmbralRaptop confused
* UmbralRaptop glares at the weather percent for only having 4 months, but I guess other reports exist
<B787_300> oO
<B787_300> yeah it is the first half of the year
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<oeuf> B787_300: I don't speak ru
<oeuf> B787_300: ask whitequark maybe
<whitequark> which diagram
<oeuf> <B787_300> UmbralRaptop: slide 3? ПогодаКоличество часов
<whitequark> hm
<whitequark> the legend says, from top to bottom: Observers; Operators; Theoretical
<whitequark> the Y axis is in observation time, hours
<UmbralRaptop> the axes make sense, though I'm not 100% clear on what they're measuring and if it corresponds to eg: science time, engineering time, and total time w/o maintenance and weather losses
<egg|zzz|egg> !wpn whitequark, UmbralRaptop, et al.
* galois gives whitequark, UmbralRaptop, et al. a vestigial helium polygon with a tail attachment
<UmbralRaptop> vestigial tail?
<kmath> <VektroidLive> FOR RESEARCH PURPOSES ONLY: https://t.co/NYW9cTiaei
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<egg|zzz|egg> !wpn
* galois gives egg|zzz|egg a harpoon
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<egg|zzz|egg> UmbralRaptop: seems to be from http://messybeast.com/small-hybrids/margarita-pallas-hybrids.htm
<egg|zzz|egg> !wpn whitequark
* galois gives whitequark a chalcogenic hammer
<egg|zzz|egg> meow
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<egg|work|egg> !u 🌩️🌩
<galois> 🌩: U+1f329 CLOUD WITH LIGHTNING
<galois> ️: U+fe0f VARIATION SELECTOR-16
<galois> 🌩: U+1f329 CLOUD WITH LIGHTNING
<kmath> <LeaksPh> with big enough error bars, everything agrees with everything!!
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<SilverFox> are there gpu sorting algorithms?
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<kmath> <AzulCrescent> Never again, she decided. https://t.co/nCJBuAlTCt
<_whitenotifier-a3da> [Principia] eggrobin reviewed pull request #2379 commit - https://git.io/Je1fM
<_whitenotifier-a3da> [Principia] eggrobin labeled pull request #2379: Get the inertia tensor of the body and push it to the plugin - https://git.io/JePtG
<_whitenotifier-a3da> [Principia] meshula starred Principia - https://git.io/Je1fb
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<kmath> <0xabad1dea> I'm sure there's an excellent reason for this and I am afraid to find out what it is https://t.co/EQAQFElSWZ
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<_whitenotifier-a3da> [Principia] pleroy reviewed pull request #2379 commit - https://git.io/Je1JF
<_whitenotifier-a3da> [Principia] pleroy synchronize pull request #2379: Get the inertia tensor of the body and push it to the plugin - https://git.io/JePtG
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<_whitenotifier-a3da> [Principia] Pending. Build queued… - 
<_whitenotifier-a3da> [Principia] Pending. Building… - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3971/
<_whitenotifier-a3da> [Principia] Success. Build finished. - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3971/
<_whitenotifier-a3da> [Principia] pleroy closed pull request #2379: Get the inertia tensor of the body and push it to the plugin - https://git.io/JePtG
<_whitenotifier-a3da> [Principia] pleroy pushed 6 commits to master [+0/-0/±33] https://git.io/Je1UL
<_whitenotifier-a3da> [Principia] pleroy 60969e8 - New parameters passed through the interface.
<_whitenotifier-a3da> [Principia] pleroy 9a60537 - Compute the inertia tensor and pass it to the plugin.
<_whitenotifier-a3da> [Principia] pleroy 4a50ad6 - C# side.
<_whitenotifier-a3da> [Principia] ... and 3 more commits.
<_whitenotifier-a3da> [Principia] pleroy opened pull request #2380: Propagate the part's angular velocity to the plugin - https://git.io/Je1Tq
<_whitenotifier-a3da> [Principia] Pending. Build queued… - 
<_whitenotifier-a3da> [Principia] Pending. Building… - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3972/
<_whitenotifier-a3da> [Principia] eggrobin labeled pull request #2380: Propagate the part's angular velocity to the plugin - https://git.io/Je1Tq
<_whitenotifier-a3da> [Principia] Success. Build finished. - http://casanova.westeurope.cloudapp.azure.com:8080/job/Principia/3972/
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<kmath> <sortiecat> @qntm The 2010's did pretty well well by being a second longer than the 2000's but four seconds shorter than the 19… https://t.co/H8iTH9GUAn
<SilverFox> wait a minute, I dont get it
<oeuf> UmbralRaptop: I wonder whether there is a betting pool on leap seconds
<UmbralRaptop> oeuf: that would be amusing
<SilverFox> are leap seconds not predictable?
<oeuf> tired: derivatives market; wired: ΔT market
<UmbralRaptop> correct. leap seconds are announced only 6 months in advance
<SilverFox> so this is the delta T in seconds for a given year because of leapseconds?
<oeuf> UmbralRaptop: but you can make some educated guesses by looking at this data
<SilverFox> this data seems rather predictable
<oeuf> SilverFox: no, this is the difference between earth orientation (UT1) and UTC (atomic time offset to remain close to earth orientation)
<oeuf> it is very much unpredictable in the short term
<SilverFox> sorry, this isn't in seconds, it's in european seconds
<oeuf> over millenia you can say things
<oeuf> and the discretization means you can bracket things
<oeuf> s/$/ on the short term/
<galois> oeuf meant to say: and the discretization means you can bracket things on the short term
<SilverFox> how specific do you have to be in the betting?
<oeuf> (hence the silly leap second betting pool idea)
<SilverFox> an idea is only silly if it doesn't work out
<oeuf> well, leap seconds can happen every 6 months
<UmbralRaptop> So, -20 to +20 over a decade
* UmbralRaptop feels like 3 is a reasonable guess
<oeuf> UmbralRaptop: oh yeah, decade-level is an option
<oeuf> UmbralRaptop: I was thinking more short term, e.g. "there will/will not be a leap second at the end of june 2020"
<SilverFox> on the three madmen
<oeuf> (or december 2020)
<UmbralRaptop> hm
<SilverFox> wait a minute, how does the leapsecond system work month by month?
<SilverFox> can you abstract it down to daily?
<oeuf> glaring at the graph, probably not june 2020, maaybe december 2020 or june 2021?
<SilverFox> or like, leapseconds/second
<UmbralRaptop> They can be announced for June 30 or December 31
<oeuf> (technically they allow for four per year, but they only use the half-year slots)
<UmbralRaptop> hm
<SilverFox> why
<SilverFox> sounds arbitrary
<SilverFox> we need daily updates like the stock market
<SilverFox> but for leap seconds
<oeuf> because the point is to keep UTC and UT1 within a second, and the earth hasn't slowed enough that frequent leap seconds are needed
<SilverFox> maybe I'm misunderstanding something, but if there's the differences in the graph, those can be averaged out over the time period, no?
<SilverFox> like, physics doesnt work in time steps like that, it's continuous
<whitequark> people actually do "smear" leap seconds in some cases
<oeuf> yeah, but that's an implementation thing rather than definitional, they're still following whatever the IERS says
<oeuf> whitequark: now, the more Exciting thing is what happened before 1972
<whitequark> ha
<oeuf> UTC varied in both rate and discontinuous leaps (of non-integer seconds)
<SilverFox> you mispelled eggciting
<oeuf> Eggsciting
<SilverFox> yes
<oeuf> whitequark: or more readably https://hpiers.obspm.fr/iers/bul/bulc/UTC-TAI.history
<oeuf> whitequark: "the fractional frequency offset was -150 parts in 10^10 during 1960 and 1961; -130 parts in 10^10 during 1962 and 1963; [...]
<oeuf> cc mofh : WWV docs
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<oeuf> whitequark: note that this means that if you use posix timestamps as they are defined before 1972, your rate changes (I think in practice people ignore what the posix wording says and just extrapolate at constant TAI offset)
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<oeuf> (arguably if you have decent second-level timestamps from 1970 you probably know better than to store your data in that ambiguous formats)
<UmbralRaptop> !choose UTC / JD
<galois> UmbralRaptop: Your options: UTC , JD. My choice: JD
<UmbralRaptop> ;choose UTC / JD
<kmath> UmbralRaptop: There wasn't any delimiters in your message. Split your choices by , or |
<UmbralRaptop> ;choose UTC | JD
<kmath> UmbralRaptop: JD
<oeuf> UmbralRaptop: well yes but JD in which timescale
<UmbralRaptop> aaaa
<oeuf> (the IAU stated that the default is TT unless otherwise specified, right?)
<oeuf> (can't remember which resolution)
<UmbralRaptop> Sounds right?
<oeuf> and obviously JD for UTC is probably nonsense
<UmbralRaptop> maybe. JD for TAI definitely is
<oeuf> UmbralRaptop: what? it's perfectly well-defined for TAI
<oeuf> for any continuous timescale really
<UmbralRaptop> oh
* UmbralRaptop was thinking more of rotational errors
<UmbralRaptop> (The moon is bad, and should feel bad?)
<oeuf> moo
<UmbralRaptop> oblate moo
* oeuf pets котеньку and whitequark