egg|nomz|egg 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.
* egg|zzz|egg
meows at bofh
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<UmbralRaptor>
Hm, only 75 minutes until launch.
<iximeow>
!wpn Parker Solar Probe
* Qboid
gives Parker Solar Probe a greening blizzard
<iximeow>
both curious how large the sun would appear at minimum approach but also how much combined pressure the sun will exert on it
<iximeow>
and tired enough i don't feel like doing the math
<egg|zzz|egg>
!acr -add:IUGG International Union of Geodesy and Geophysics
<Qboid>
egg|zzz|egg: I added the explanation for this acronym.
<bofh>
egg|zzz|egg: huh, interesting.
<bofh>
also I don't think continental drift happens at fast enough time scales to be relevant for Principia
<egg|zzz|egg>
bofh: context: phl is working on adding higher (tesseral) gravitational harmonics
<egg|zzz|egg>
that's what the sincos was for
<egg|zzz|egg>
how do you test that to catch a sign error or an off-by-π/2?
<egg|zzz|egg>
so my idea was to see what happens to a high-altitude passive geodesy satellite
<egg|zzz|egg>
if I work directly from the laser ranging data I need to care about the realization of the ITRF (incl. continental drift)
<egg|zzz|egg>
bofh: otoh the ILRS products do include fits; however, those fits are in the ITRF so at least I need to convert that to the IRCF and to do that I need to care about the wobbly pole
<egg|zzz|egg>
halp
<bofh>
10:07:54 <@egg|zzz|egg> how do you test that to catch a sign error or an off-by-π/2?
<bofh>
10:08:29 <@egg|zzz|egg> so my idea was to see what happens to a high-altitude passive geodesy satellite
<bofh>
okay, that *would* work
<bofh>
...in fact I think that's the simplest approach, even.
<egg|zzz|egg>
bofh: well, it seems like the safest approach at least, because other lower-level approaches are too likely to have independent errors that match up
<bofh>
eggsactly.
<egg|zzz|egg>
bofh: and clearly we can't take that risk in Principia,
<egg|zzz|egg>
ferram4: why is FAR a resource for DO-178B,
<egg|zzz|egg>
bofh: do you think I can ignore the polar wobble and variations in rotation rate for the ITRF-to-ICRF conversion, or would that drown the effect of the harmonics
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<bofh>
polar wobble *may* be necessary, otherwise the rest seems ignorable.
<egg|zzz|egg>
bofh: well it all depends on how many harmonics you're considering, doesn't it,
<egg|zzz|egg>
!acr -add:DOMES Directory Of MERIT Sites
<Qboid>
egg|zzz|egg: I added the explanation for this acronym.
<egg|zzz|egg>
DORIS?
<Qboid>
egg|zzz|egg: [DORIS] => Détermination d'Orbite et Radiopositionnement Intégré par Satellite / Doppler Orbitography and Radiopositioning Integrated by Satellite
<egg|zzz|egg>
MERIT?
<egg|zzz|egg>
!acr -add:MERIT Monitor Earth Rotation and Intercompare the Techniques of observation and analysis
<Qboid>
egg|zzz|egg: I added the explanation for this acronym.
<egg|zzz|egg>
bofh: how does this compare to NMR acronyms
<egg|zzz|egg>
bofh: note the 2-language acronyms where the letter D stands for completely different things
<egg|zzz|egg>
bofh: oh, this is useful: interpolating iers earth orientation data
<egg|zzz|egg>
right now the principia constexpr UT1 literals do linear interpolation
<egg|zzz|egg>
... then again constexpr Lagrange interpolation sounds hard
<egg|zzz|egg>
what with the trig lines not being constexpr
<egg|zzz|egg>
GCRS?
<Qboid>
egg|zzz|egg: [GCRS] => Geocentric Celestial Reference System
<egg|zzz|egg>
5.5.1.1 Account of ocean tidal and libration effects in pole coordinates xp and yp
<egg|zzz|egg>
The subdaily variations are not part of the polar motion values reported to and distributed by the IERS and are therefore to be added after interpolation. This is appropriately done by the routine “INTERP.F” of the IERS EOP Product Center, which interpolates series of xIERS, yIERS values to a chosen date and then adds the contribution for this date of (i) the tidal terms (∆x, ∆y)ocean tides deriv
<egg|zzz|egg>
ed from Tables 8.2a and 8.2b, and (ii) the diurnal components of the (∆x, ∆y)libration terms, derived from Table 5.1a.
<egg|zzz|egg>
bofh: ^
<egg|zzz|egg>
bofh: admittedly I guess you can use the tables, but the spec explicitly refers to a bit of FORTRAN, so that's a start
<Qboid>
egg|zzz|egg: I added the explanation for this acronym.
<egg|zzz|egg>
UmbralRaptor: bofh: IAU 2006 Resolution B2 on the Supplement to the IAU 2000 Resolutions on reference systems: Recommendation 1. Harmonizing the name of the pole and origin to “intermediate”: The XXVIth International Astronomical Union General Assembly, [...] Recognizing [...] 2. that the name “Conventional International Origin” with the potentially conflicting acronym CIO is no longer commonly
<egg|zzz|egg>
used to refer to the reference pole for measuring polar motion as it was in the past by the International Latitude Service, [...] 2. that the terminology “Celestial Intermediate Origin” (CIO) [...] be used in place of the previously introduced “Celestial Ephemeris Origin”
<egg|zzz|egg>
(Celestial Ephemeris Origin) [...], and 3. that authors carefully define acronyms used to designate entities of astronomical reference systems to avoid possible confusion.
<bofh>
eep
<egg|zzz|egg>
bofh: :D
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<egg|zzz|egg>
bofh: hmm, one problem with using that data for our tests is that there's *a lot* of it
<egg|zzz|egg>
bofh: one position & velocity record every 2 min since 2016....
<egg|zzz|egg>
bofh: and I don't think I want to check in *that much* crap
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<egg|zzz|egg>
!wpn whitequark
* Qboid
gives whitequark a signalling rotor
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<egg|zzz|egg>
!u :||
<Qboid>
U+003A COLON (:)
<Qboid>
U+007C VERTICAL LINE (|)
<Qboid>
U+007C VERTICAL LINE (|)
<egg|zzz|egg>
!u 𝄇
<Qboid>
U+1D107 MUSICAL SYMBOL RIGHT REPEAT SIGN (𝄇)
<kmath>
<stephentyrone> Baby’s first rhythm: surprisingly complex. ⏎ ⏎ ||: . 2 3 . | 1 .+.+. :|| ⏎ ⏎ Definitely not what I expected her to bust o… https://t.co/3raKuIpQls
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<egg|zzz|egg>
Ellied: where did you get your glasses grating?
<bofh>
egg|zzz|egg: I actually have no idea, it's really weird. I've seen it before, but don't know how to read.
<egg|zzz|egg>
!acr -add:TIRS Terrestrial Intermediate Reference System
<Qboid>
egg|zzz|egg: I added the explanation for this acronym.
<egg|zzz|egg>
bofh: formally (and ignoring the fact that this is concentrated pedantry because we are not yet at the point where the distinction matters), should we say that we are manipulating vectors in the ICRS or the ICRF? (same question for ITRS/ITRF obviously)
<bofh>
hrm.
* UmbralRaptor
x_x
<egg|zzz|egg>
UmbralRaptor: ^ same question
* UmbralRaptor
accidentally stayed up and watched Parker Solar Probe launch
<egg|zzz|egg>
ow i missed that
<egg|zzz|egg>
we should really think of adding kountdowns to Qboid...
<egg|zzz|egg>
!kd next
<Qboid>
egg|zzz|egg: Sequence contains no elements
<egg|zzz|egg>
!kd -list
<Qboid>
egg|zzz|egg: Invalid list argument! Valid arguments are 'events' and 'subs'.
<egg|zzz|egg>
!kd -list events
<Qboid>
egg|zzz|egg: Invalid list argument! Valid arguments are 'events' and 'subs'.
<egg|zzz|egg>
!kd -list:events
<Qboid>
egg|zzz|egg: I sent you a list of all Kountdown events.
<egg|zzz|egg>
bofh: so the *F are realizations of the *S
<UmbralRaptor>
" For very precise reductions it is necessary to use a fully GR-based approach… "
<egg|zzz|egg>
in the same way that TT(BIPM) is a realization of TT
<egg|zzz|egg>
and TAI + 32.184 is another (poorer) realizatino of TT
<egg|zzz|egg>
BIH?
<Qboid>
egg|zzz|egg: [BIH] => Bureau International de l'Heure
<bofh>
egg|zzz|egg: *stare*
<bofh>
egg|zzz|egg: also I *think* ICRF is appropriate here but... that's a tricky question.
<egg|zzz|egg>
bofh: the thing is, what does ICRF mean without versioning
<egg|zzz|egg>
what point is there in distinguishing ICRF and ICRS if I'm not saying "this is ICRF2008"
<egg|zzz|egg>
s/C/T/
<Qboid>
egg|zzz|egg meant to say: what point is there in distinguishing ITRF and ICRS if I'm not saying "this is ICRF2008"
<egg|zzz|egg>
s/C/T/g
<Qboid>
egg|zzz|egg meant to say: what point is there in distinguishing ITRF and ITRS if I'm not saying "this is ITRF2008"
<bofh>
point, but don't we typically assume the most recent of each if it's not specified?
<egg|zzz|egg>
(at which point, you need to port things that are in ITRF2005 to ITRF2008 to use them together obviously)
<egg|zzz|egg>
bofh: well, the data I get is decent, so it tells me it's ITRF2008
<egg|zzz|egg>
at least the data I get from ILRS, JPL might be sloppier
<bofh>
okay, point.
<egg|zzz|egg>
bofh: but if I'm assuming that I can be sloppy enough to ignore the distinction between ITRF2005 and ITRF2008, surely the distinction between the ITRFs and the ITRSes is meaningless? but then what I have might as well be the ITRS given how sloppy I am
<egg|zzz|egg>
bofh: otoh if I do distinguish them then the ITRS might as well not exist, the closest I have is ITRF2014 and I want to keep track of the fact it is that for when ITRFfancier comes about
<kmath>
<✔afneil> Fleeing the scene of a road accident in Paris because he didn’t have a licence, a French driver unwittingly climbed… https://t.co/xguWvBYxL2
<bofh>
UmbralRaptop: mostly, to cool off & see the Northern Lights.
<bofh>
I mean I wanted to when I was in Helsinki but it never got bloody dark enough... OTOH I think Svalbard'd have that problem too, but worse.
<kmath>
<Cinderforgsword> Two Atelier cosplayers, @FioraAeterna and @mirihawke , just won Best in Show for Otakon's hall cosplay contest. ⏎ ⏎ Go… https://t.co/yrbrt0wMmF
<egg|zzz|egg>
!acr -add:GGM GRACE Gravity Model
<Qboid>
egg|zzz|egg: I added the explanation for this acronym.
<egg|zzz|egg>
bofh: I don't think she's in this channel anymore :-/
<egg|zzz|egg>
;seen fiora
<kmath>
egg|zzz|egg: fiora (fiora!~Fiora@ec2-54-82-190-77.compute-1.amazonaws.com) was last seen quitting in somewhere at 2018-07-12 18:59:41 +0000
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<egg|zzz|egg>
GOCE?
<Qboid>
egg|zzz|egg: [GOCE] => Gravity Field and Steady-State Ocean Circulation Explorer
<kmath>
<Foone> This is what happens when you try to use a registered nickname at Pantera Bread. ⏎ Damn you, nickserv! https://t.co/piSHXy1MvP
<egg|zzz|egg>
<egg|zzz|egg> Ellied: where did you get your glasses grating?
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<UmbralRaptop>
egg|zzz|egg: unsure, but rainbow symphony sells lots of plastic gratings.
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<bofh>
UmbralRaptop: dunno if they meant Panera Bread, or if there's an actual Extremely Metal bakery called Pantera Bread.
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<UmbralRaptop>
bofh: I'm blaming autocarrot
<bofh>
UmbralRaptop: personally I want to go to the actual, literal Pantera Bread. \m/
<UmbralRaptop>
bofh: if nothing else, the background music would be good.
<bofh>
UmbralRaptop: Indeed.
* UmbralRaptop
hopes that the food would use the astronomical definition of metals.
<bofh>
LOL
<bofh>
I wonder what the metallicity of a typical baguette'd be.
<UmbralRaptop>
"[Fe/H] is in line with solar values, however the pastries are immensely enriched in alpha elements. In particular, we find that the [O/H] of the baguette is approximately +1.6."
<Ellied>
egg|zzz|egg: rainbow symphony, yeah. I got a pack of 10 on Amazon.
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<egg|zzz|egg>
!meow bofh
* Qboid
meows at bofh
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<egg|zzz|egg>
!meow bofh
* Qboid
meows at bofh
<egg|zzz|egg>
!meow bofh
* Qboid
meows at bofh
<egg|zzz|egg>
!wpn bofh
* Qboid
gives bofh a dysprosium correction
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<egg|zzz|egg>
bofh: hm, my phone seems to have flaky wifi now
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<egg|zzz|egg>
I wonder whether that's linked to being dropped in paris
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<egg|zzz|egg>
!wpn bofh
* Qboid
gives bofh a graded épée
<egg|zzz|egg>
!wpn Ellied
* Qboid
gives Ellied a Minkowsky square
<egg|zzz|egg>
!wpn UmbralRaptop
* Qboid
gives UmbralRaptop a conjugate 雪風
<egg|zzz|egg>
!wpn whitequark
* Qboid
gives whitequark a burnt timezone-like implosion
<egg|zzz|egg>
bofh: are there any upcoming flights to add to Qboid's kountdown?
<bofh>
not off the top of my head, check spaceflightnow I s'pose?
<kmath>
<Foone> he's also an Officer of the Order of Agricultural Merit, cause of course the French give out honors to those who ha… https://t.co/CiROB5VJTv