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>
bofh: somehow this menu reminds me of superdupont in its over-the-top frenchiness
<egg>
bofh: also the thing at the bottom-right i guess
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<egg>
(and "hamburgé", obviously [ɑ̃byʁʒe])
<egg>
(i mean, that's how you would read "hamburger" in french, but since people know that it's pronounced in some attempt-at-english way, spelling it "hamburgé" makes the [ɑ̃byʁʒe] eggsplicit :-p)
<egg>
bofh: note the role of the "h" in french, it's "du hamburgé", not "de l'hamburgé", but there's obviously no [h]
<bofh>
I mean I feel like we went over this with "Le Havre" as an eggsample in the past.
<bofh>
I mean I'm not surprised; actually I'm much more surprised that semi-analytic theories for mean elements are tractable in any capacity.
<egg>
bofh: and by tractable you mean that every paper cites five different theories,
<egg>
and then randomly picks a few and waves hands
<bofh>
okay yeah that's pretty much eggsactly what I was eggspecting.
<bofh>
look, mean elements are HARD.
<egg>
yes but how do i do something useful in principia
<egg>
i could try having nodal & anomalistic periods
<bofh>
I think this is turning into a research problem tbh.
<egg>
since those are just durations between discrete times
<bofh>
anomalistic periods seems like the simplest shortcut?
<egg>
but that's for one orbit, should I average them?
<egg>
and I need to detect wonkiness ideally, e.g. for a near circular orbit anomalistic periods are meaningless
<egg>
and there will likely be four apsides per orbit
<egg>
(perturbations dominating the ellipse)
<bofh>
Try and see? But yeah that might be tricky. I'm confused why you need *semi-analytic theory* for mean elements as opposed to *just the mean elements themselves*, tho.
<egg>
well
<egg>
the semi-analytic theory is what allows you to define the mean elements
<egg>
otherwise, what is a mean element
<egg>
you can't just take random shit, integrate it and call it an integral of motion
<egg>
it is not going to be an integral of motion
<egg>
bofh: the point with mean elements is that they should be constant
<bofh>
I mean I'm used to just, say, the mean anomaly being either a constant or an expression in time.
<egg>
uuuuuuuuuuh
<bofh>
B/c over large timescales mean elements for solar system objects fail to be, well, constant.
<egg>
let's not talk about the mean anomaly because it's confusing, it's an element with the word mean in it
<egg>
I have seen several paper with "mean mean anomaly" in them today
<egg>
let us not go there
<egg>
bofh: the idea is that you have osculating elements easily
<bofh>
okay those are pretty nasty dragons
<bofh>
that is a nice idée, that I have never seen done in reality.
<egg>
bofh: by textbook application of Kepler on the state vectors
<bofh>
in reality osculating elements are HARD
<egg>
no, they're fine
<bofh>
like they're nice to work with, they're incredibly hard to *derive*.
<egg>
bofh: but they vary over the course of an orbit
<egg>
no they're trivial
<egg>
and they're not nice to work with, they vary at high frequency
<egg>
they're the thing that gets shown in MJ if you use principia
<bofh>
I mean they're trivial for a small timespan, but if you want accurate elements that hold for [large timespan], then the derivation becomes hard.
<egg>
then they're not osculating
<egg>
they're proper, or mean
<egg>
osculating means osculating
<egg>
like osculating circle
<egg>
except osculating Kepler orbit
<egg>
it's a local property
<egg>
the unique Kepler orbit through this point with this velocity at this time
<bofh>
OKAY, I finally understand the distinction between mean and osculating; that's confused me for months.
* bofh
facepalms at self
* egg
meows at bofh
* egg
pokes bofh with a mean mean motion
<egg>
(it wasn't mean mean anomaly, that's absurd, it was mean mean motion)
<kmath>
<cartoon_physics> PSA for researchers: no matter how useful you’ve found Marie Kondo’s advice, you are not allowed to throw out the p… https://t.co/IjGW1NeqHH
<kmath>
YouTube - Have You Ever Seen A Croissant Like This ? (New Series)
<egg>
bofh: btw have you cooked anything interesting since returning to CA
<bofh>
I mean mean motion is just the first derivative of the mean anomaly, so the mean mean anomaly should be definable in terms of the mean mean motion and an epoch
<bofh>
I think
<bofh>
and no. also heading to US in 2 days, can't *wait* to wander into the tire fire
<bofh>
(note: I do not want to wander into the tire fire. At all).
<UmbralRaptop>
Oh, CA the country, not the state.
<egg>
bofh: you can cook while not looking at the news
<egg>
bofh: that way you don't look at the tire fire and get better at food,
<kmath>
<Tom_Ruen> Here's a full 496 year animation, with Neptune held to the right. This is just 2-body motion, without Neptune's inf… https://t.co/qASfkOgO1a
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<UmbralRaptop>
DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation)
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[Principia] pleroy labeled issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/f4FKp
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[Principia] pleroy opened pull request #2064: Propagate errors found during integration to kill the vessel - https://git.io/fhniw
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[Principia] pleroy synchronize pull request #2064: Propagate errors found during integration to kill the vessel - https://git.io/fhniw
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[Principia] eggrobin labeled pull request #2064: Propagate errors found during integration to kill the vessel - https://git.io/fhniw
<egg>
meow
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[Principia] pleroy synchronize pull request #2064: Propagate errors found during integration to kill the vessel - https://git.io/fhniw
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[Principia] pleroy synchronize pull request #2064: Propagate errors found during integration to kill the vessel - https://git.io/fhniw
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[Principia] pleroy pushed 12 commits to master [+2/-0/±21] https://git.io/fhnXF
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[Principia] eggrobin c0add94 - switch to directly calling dbghelp, dbh is a mess
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[Principia] eggrobin ab2dd62 - split out DbgHelp
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[Principia] eggrobin 88dcbf0 - more formatting
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[Principia] ... and 9 more commits.
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[glog] eggrobin pushed 1 commit to master [+0/-0/±1] https://git.io/fhn1e
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[glog] eggrobin 47451c1 - Include the frame with the check when dumping the stack trace.
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[Principia] pleroy commented on pull request #2064: Propagate errors found during integration to kill the vessel - https://git.io/fhn1n
<egg>
Sarbian: have you looked at 1.6, are the Δv readouts garbagey?
<Sarbian>
I did not really look into it. I know it does not work with RF
<Sarbian>
The number looked ok on stock
<egg>
not working with RF is going to make things confusing when using RF :-p
<Sarbian>
it can be turned off easily
<egg>
good news :-)
<Sarbian>
DELTAV_CALCULATIONS_ENABLED and the other DELTAV_* keys in settings
<egg>
Sarbian: meanwhile, I'm on your moon, changing your orbits https://forum.kerbalspaceprogram.com/index.php?/topic/162200-wip131-14x-151-principia%E2%80%94version-%CE%B5%E1%BD%94%CE%B4%CE%BF%CE%BE%CE%BF%CF%82-released-2018-01-06%E2%80%94n-body-and-extended-body-gravitation-axial-tilt/&page=48&tab=comments#comment-3517634
<Sarbian>
I saw your tweets
<egg>
I should probably start looking at the topography
<egg>
because when orbits move a lot like this, it starts to matter whether there's a mountain or not :-p
<kmath>
<jeff_foust> “In a statement, NASA says that it does not expect the ongoing US government shutdown to affect efforts to repair H… https://t.co/r9hyuo7Hc7
<bofh>
UmbralRaptop: *stare*
<SnoopJeDi>
s/affect/effect/
<SnoopJeDi>
(for a cheeky lolsob joke, that is; it's correct as-is for the meaning intended)
<SnoopJeDi>
NASA also says things like "JWST will launch on time" so
<SnoopJeDi>
¯\_(ツ)_/¯
<UmbralRaptop>
bofh: have I mentioned that I'm involved in a NASA project, so this shutdown has pushed some deadlines back, uh, 26 days now?
<UmbralRaptop>
(shutdown + 3)
* bofh
hugs UmbralRaptop
<bofh>
my condolences :/
* UmbralRaptop
hugs bofh back
<UmbralRaptop>
It's not too painful at this point, at least.
<kmath>
<willkirkby> ā̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄̄ ⏎ ⏎ That's a lowercase A followed by 48 instances of U+0304 COMBINING… https://t.co/JmtWZ2SfKI
<kmath>
<3blue1brown> New video! If the answer here does not blow your mind, I don't know what will. In short, how does this number of… https://t.co/vCOuYWJpbF
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[Principia] eggrobin commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhnHt