raptop 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
<egg>
UmbralRaptop: what
<UmbralRaptop>
at the overlap between the two schools
<egg>
UmbralRaptop: lɒl
<egg>
UmbralRaptop: Switzerland!
<egg>
UmbralRaptop: you have a federal school and a cantonal school
<egg>
UmbralRaptop: so across the streets on two sides of the ETHZ main building, you have the university main building and the university hospital :D
<egg>
yes the main buildings are adjacent :-p
<UmbralRaptop>
o_O
<egg>
"For Molniya, the tesseral harmonic coefficients with the most effect are C22, C32, C52; C44, C54, C64; C66, C76, C86; C98 and the corresponding Slm."
<kmath>
<CoreyStoughton> I would like to congratulate the Parliament of the United Kingdom tonight for demonstrating, possibly for the first… https://t.co/cXuXImlms0
<UmbralRaptop>
Okay, but on this side of the Atlantic…
* egg
pokes bofh in the calendar
* UmbralRaptop
attaches a light to bofh's calendar.
* egg
swats bofh with a calendar
* egg
stares at apparent secular drift of the sidereal period Ꙩ_ꙩ
* UmbralRaptop
blames the moon
* egg
bites the moon
<bofh>
egg: I was getting food, okay >_<
<egg>
UmbralRaptop: it's not the moon, it's overly lax integration tolerance on a nonsymplectic integrator, oops
<UmbralRaptop>
oh
<bofh>
can you switch to a symplectic one here?
<egg>
bofh: sure but what timestep should I choose
<egg>
(note: here I was using a high order adaptive stepsize method with a tolerance of ~265 m over 40 years)
<egg>
265 isn't a horrible tolerance, but over 40 years you do see the nonsymplecticity
<bofh>
Hrm. I wonder if reducing it to, like, 195m or so would change anything at all.
<egg>
bofh: reducing to 26 m leads to little appreciable drift
<egg>
(mind you this is a молния orbit which won't last anywhere near 40 years IRL because atmosphere but principia does not model that)
<bofh>
I mean imagine hydrazine thrusters that auto-trigger,
<egg>
bofh: so assuming we get rid of the atmosphere (it's silly anyway), after 30 000 orbits I have T🜨 / T* = +2.000873(76)
<egg>
that's quite a few sigdec
<bofh>
Why +2 and not +0?
<egg>
because two orbits per earth revolution?
<bofh>
Oh, right, that's a difference
<bofh>
and also Molniya
<bofh>
right.
<bofh>
okay, that's not bad actually.
<egg>
T🜨 / T* being the earth's sidereal rotation period over the satellite's sidereal period
<egg>
bofh: mind you there's an 8 at the last sigdec that makes it not-quite-synchronous in a statistically significant way, but that's just my initial conditions being a poor молния orbit, the goal here is to see if I can get a good standard uncertainty on T* eventually
<egg>
bofh: that's actually the uncertainty on 1/T*, the original is T* = +4.30632(16) × 10^+4 s
<egg>
and aside from the fact that randomly disunifying things is a terrible idea, there's no useful distinction between the two for text processing; they have the same glyph in any correct typesetting, and the semicolon is not script-specific
<bofh>
I mean in that case why have both in the first place?
<egg>
bofh: this I do not know, I suspect some obscure encoding had ASCII + greek question mark?
<kmath>
<jen_gupta> Apparently today is the launch of the International Year of the Periodic Table so I thought it was time to introduc… https://t.co/4BoWzHiFFF
<egg>
bofh: see also: all the other canonical decompositions
<egg>
bofh: nevermind I had stray 0 in my data, it's actually T🜨 / T* = +2.0008066(91)
<egg>
which is quite a few sigdec
<bofh>
Ehh. That's *still* not bad over 40 years integrated, no?
<egg>
bofh: that's better, it was T🜨 / T* = +2.000873(76) previously
<egg>
yeah they made a new book because the old one was out of print, changing the presentation in some places, adding satellites, adding a part on geodesy and one on GPS
<bofh>
Ooh, this looks interesting.
<bofh>
And yeah, generally if it's more than a few years old it'll be out of print
<bofh>
So you're looking at a new edition
<bofh>
Which can be anything from renumbering the exercises (OH HAI STEWART'S CALCULUS AND EARLY TRANSCENDENTALS) to basically a total overhaul of the textbook.
<egg>
bofh: the table of contents seems very similar
<egg>
bofh: I guess I could buy both and compare U+1F92A
<SnoopJeDi>
Stewart's book is too good for its industry :(
<egg>
bofh: (note, there are english versions but if I'm going to buy it in print why not get the original :-p)
* egg
stares at T☊ = +43064.68(20) s, T* = +43064.68(20) s
<bofh>
I mean that's pretty good, no?
<egg>
bofh: why are they the same
<bofh>
luck?
<egg>
bofh: also, calendar
<bofh>
And yeah, I'd be tempted to get the French ver in print just b/c FR vocabulary is useful.
<egg>
bofh: I can buy it and you can read it at ANBO next time you're around I guess :-p
<egg>
also T = +43064.68(20) s (that's anomalistic)
<egg>
<bofh> luck? << 9 digit luck?
<bofh>
03:16:09 <@egg> bofh: I can buy it and you can read it at ANBO next time you're around I guess :-p
<bofh>
works for me
<bofh>
(oh, do you have an entry to add to the 'when is mofh going to move to Paris' betting pool? :P)
<kmath>
<KhaledGhetas> ECMA TR/53 uses the acronym BDSM for terminal Bi-Directional Support Mode, and I hope that was intentional because… https://t.co/yg1e3MGAXV
<bofh>
okay, yeah, that makes sense in retrospect.
* bofh
facepalms
<egg|work|egg>
⟨bofh⟩ Le Louvre at least does until 29. ⮜ well, it has several tiers, it is cheaper in [0, 26[ than in [26, 30[
<bofh>
Yes, but it has reasonably priced costs in [26,30[ still. Philharmonie de Paris *only* does [0,28[, which is super-annoying since prices jump from reasonable to silly w/o a youth subscription.
<bofh>
(Tho I'm actually genuinely surprised I hadn't tried to sneak in; I suspect that it's b/c none of the concerts that played during my time in Paris were appealing enough to try that).
<bofh>
(Alternatively, I was just too damn busy, lmao).
<UmbralRaptop>
bofh:… how hard was it to get a room to crash in Zürich? (a student lounge in ETHZ doesn't count)
<bofh>
UmbralRaptop: surprisingly easy, like it took me about 20 minutes on booking.com to find and book a hôtel.
<bofh>
okay, it took more like 8 hours, but most of that was egg yelling at me to get a room and me deciding to teach econ students linear programming instead.
<UmbralRaptop>
Heh
<egg>
bofh: even at 30 it's not that bad at the Louvre
<egg>
it goes 15 35 80
<bofh>
80 gets you 2.5 concerts at the Philharmonie at normal prices, 4 if you're crazy lucky with ticketing.
<bofh>
Also I just realized that's a lie, I *did* crash a concert, but it was a random thing done at Saint-Julien-le-Pauvre, not a Philharmonie one.
<egg>
bofh: also clean up your calendar already
<bofh>
fine
<egg>
UmbralRaptop: yeah, bofh also randomly ended up picking a hotel just down the street from where i am so you can do that too
<UmbralRaptop>
Okay. So 5 hours (EDT ↔ CET) for the duration I'm interested in.
<egg>
UmbralRaptop: convert everything to TT, express in julian dates,
<UmbralRaptop>
I won't be operating any observatories, though. Just a poster.
<egg>
UmbralRaptop: roll up the poster, put a lens in
<egg>
bofh: moo
<bofh>
egg: ?
<egg>
bofh: calendar
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[Principia] eggrobin commented on issue #1841: Show ☊ and ☋ with respect to the equator in body-centred inertial frames - https://git.io/fhDkR