egg changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is Гельфонд. We currently target 1.8.1, 1.9.1, and 1.10.1. <scott_manley> anyone that doubts the wisdom of retrograde bop needs to get the hell out | https://xkcd.com/323/ | <egg> calculating the influence of lamont on Pluto is a bit silly… | <egg> also 4e16 m * 2^-52 is uncomfortably large
<raptop>
Select a reference frame that means that earth is not the center of the solar system?
* raptop
is confused by some of the planets not doing weird rosettes, though
<discord->
Stonesmile. — Ecef vs eci I believe
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<discord->
lpg. — speaking of reference frames, is there a way to stop the game from automatically switching between `*C*F` and `*CI` when passing certain altitude tresholds?
<discord->
egg. — this is a consequence of a a stock « feature » (whereby the velocity changes from surface to inertial at some altitude)
<discord->
egg. — unsure how hard it would be to kill it, unsure whether some might miss it, also being a somewhat independent stock thing perhaps killing it should be the job of a separate mod ?
<raptop>
The reference frame change, or the surface -> orbit switch on the navball?
<discord->
egg. — those are coupled in Principia
<discord->
egg. — the speed display always shows the speed in the current reference frame
<raptop>
ah
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<_whitenotifier-8975>
[Principia] Kerbinator-CN opened issue #2823: [New Feature] Orbit Inspector for non-repetitive orbit analysis - https://git.io/JLyi9
<discord->
Zeusbeer. — You are now stuck with cat till he decides that he's hungry
<discord->
Butcher. — I kicked her off. 😿
<discord->
Kerbinator. — 😶
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<discord->
egg. — @Butcher can you open an issue for the target prediction thingy lest I forget? I’d like to unbreak that in the next release, not having a prediction when doing rendez-vous sounds rather annoying
<discord->
Stonesmile. — Just throwing another data point into the mix; it *does* work for me for some reason 🤷♂️
<discord->
egg. — curiouser and curiouser
<_whitenotifier-8975>
[Principia] RCrockford opened issue #2824: Predicted trajectory updates very slowly whilst a target is selected - https://git.io/JLSvr
<_whitenotifier-8975>
[Principia] eggrobin labeled issue #2824: Predicted trajectory updates very slowly whilst a target is selected - https://git.io/JLSvr
<_whitenotifier-8975>
[Principia] eggrobin assigned issue #2824: Predicted trajectory updates very slowly whilst a target is selected - https://git.io/JLSvr
<discord->
egg. — oh, it does not affect the target LVLH frame? fun
<discord->
Butcher. — It;s not super consistent, sometimes it works slowly, others it;s completely frozen. If you're in target ref frame it works normally.
<discord->
Butcher. — It's not super consistent, sometimes it works slowly, others it;s completely frozen. If you're in target ref frame it works normally. (edited)
<discord->
egg. — OK, so less gamebreaking than I feared
<discord->
egg. — still a dumb regression
<discord->
Stonesmile. — That's a different situation than I thought; mine might not work either then
<discord->
Butcher. — Yes, I noticed it when I was trying to rendezvous with my lunar station - I was setting up the TLI burn with the station targetted to get into an approximately correct intercept.
<discord->
Butcher. — Once I got into orbit and was doing phasing and inclination correction it was all fine as I was in the target LVLH frame.
<discord->
egg. — I have been thinking about the « ±1 revolution button » thing lately, and about how to deal with the 57 varieties of « 1 revolution » (anomalistic, e.g., next apogee? nodal, e.g., next node? sun-synodic, e.g. for constant ejection angle from a parking orbit?) Having a host of buttons for all of those kinds of things seems wildly impractical, especially since they would all do roughly the
<discord->
egg. —
<discord->
egg. — I am thinking, instead, of having a way to change how a manœuvre is *anchored*, i.e., instead of just burning Δt after the previous manœuvre, burn after the mean anomaly/mean argument of latitude/local mean solar time has advanced by `2π * number of revolutions`. Changing the number of revolutions can then be achieved by changing the integer part of that field.
<discord->
egg. — This would have the nice side-effect that an anomalistically anchored manœuvre would stay at apogee when you move earlier manœuvres, etc.
<discord->
egg. — thoughts?
<discord->
egg. — This would have the nice side-effect that an anomalistically anchored manœuvre at apogee would stay at apogee when you move earlier manœuvres, etc. (edited)
<discord->
lpg. — alternatives to "Δt after the previous manœuvre" sounds useful. I have no idea about those particular examples
<discord->
Stonesmile. — How much math would this force the end user to do compared to a way of selecting different meanings of a revolution?
<discord->
egg. — editing a number in a text field, e.g., changing `3.5 revolutions` to `4.5 revolutions`
<discord->
Stonesmile. — Would this be able to fix a burn to lunar pe after TLI?
<discord->
egg. — and other than that this *is* a way of selecting a different meaning of revolution, it just ties into the existing UI instead of adding to the tax form
<discord->
egg. — Probably not, because you are not in lunar orbit before capture, so we cannot run the analyser there
<discord->
Stonesmile. — Understandable
<discord->
lpg. — not being able to run the analyzer on the "outcome" of a flight plan is a limitation I've been running into a lot lately
<discord->
egg. — yeah that is a prerequisite for most of this anyway; I should get around to adding it
<discord->
egg. — also, it is good to know that you are running into limitations related to the analyzer, that means it is useful to start with :D
<discord->
egg. — [Hooray, I’m useful! I’m having a wonderful time! (V) (;,;) (V)]
<discord->
egg. — Hooray, I’m useful! I’m having a wonderful time! (V) (;,;) (V) (edited)
<discord->
egg. — Hooray, I’m useful! I’m having a wonderful time. (V) (;,;) (V) (edited)
<discord->
lpg. — keeping satellites in orbit of Io and Europa would be quite the pain without it
<discord->
(experimentalshells?). — I could see an instance where this might cause a problem, but I'm unsure.
<discord->
(experimentalshells?). — If one is on a Keplerian (for the sake of example) orbit with a period of 240 minutes, and their mean/true anomaly at t = 0 is 0, they, for example, could plot a manœuvre at t = 121 and another at apoapsis. If they then perform an unscheduled engine burn in the tangential direction, increasing the apoapsis, then the order of the two future manœuvres would be reversed. Will this cau
<discord->
(experimentalshells?). — If one is on a Keplerian (for the sake of example) orbit with a period of 240 minutes, and their mean/true anomaly at t = 0 is 0, they, for example, could plot a manœuvre at t = 121 and another at apoapsis. If they then perform an unscheduled engine burn in the tangential direction, increasing the apoapsis, then the order of the two future manœuvres would be reversed. Will this cau
<discord->
lpg. — I'd sort of expect all maneuvers to _always_ use "after the last maneuver" as a lower bound, regardless of other "anchors"
<discord->
Butcher. — @egg what happens if you're not in orbit?
<discord->
(experimentalshells?). — that is the issue, the apoapsis manœuvre was scheduled before the t = 121 manœuvre. but then they switched.
<discord->
(experimentalshells?). — we just need to make sure that this is not a problem.
<discord->
egg. — oh yeah that is a good point I am saying inconsistent things
<discord->
egg. — if it is some ΔM or Δu after the last manœuvre, it is not at fixed M or u
<discord->
Butcher. — If I'm on a trajectory that ejects my probe from the solar system, there isn't another revolution.
<discord->
egg. — if things are not applicable your manœuvre would become anomalous and you would have to switch to time-based
<discord->
egg. — but this is the part that is worrisome, what do I want exactly
<discord->
egg. — is it ΔM, or is it M
* discord-
egg. — ponders
* discord-
egg. — goes to fetch some wood
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<discord->
Butcher. — I fetched wood this morning, it is a useful task.
<discord->
lpg. — > but then they switched.
<discord->
lpg. — I'm saying I'd expect that they _cannot_ switch. the initial maneuvers would _not_ be "t=121" and "apoapsis (t=120)", they'd be "apopasis (t=120)" and "t=last+1". changing the Ap would preserve that
<discord->
lpg. — > but then they switched.
<discord->
lpg. — I'm saying I'd expect that they _cannot_ switch. the initial maneuvers would _not_ be "t=121" and "apoapsis (t=120)", they'd be "apopasis (t=120)" and "t=apoapsis+1". changing the Ap would preserve that (edited)
<discord->
lpg. — > but then they switched.
<discord->
lpg. — I'm saying I'd expect that they _cannot_ switch. the initial maneuvers would _not_ be "t=121" and "apoapsis (t=120)", they'd be "apoapsis (t=120)" and "t=apoapsis+1". changing the Ap would preserve that (edited)
<discord->
(experimentalshells?). — this sounds good right up until I burn my engines and inject into an escape trajectory
<discord->
(experimentalshells?). — wheeeeeee
<discord->
lpg. — then Ap becomes Ap around the sun 😛
<discord->
(experimentalshells?). — not sure that would help things rather than make things worse
<discord->
(experimentalshells?). — perhaps I didn't pick up on your sarcasm?
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<discord->
lpg. — once you've changed trajectory that radically, I don't expect there's going to be much value in any part of an existing flight plan
<discord->
(experimentalshells?). — that's fair.
<discord->
lpg. — _except_, perhaps, the entertainment value of seeing what principia makes of it
<discord->
egg. — indeed; at this point the only thing that matters is that it doesn’t crash, but if it says « nope, get back into orbit » that is fine
<discord->
lpg. — we're all here for the unexpected noodles, after all
<discord->
egg. — but yes, @experimentalshells raises a good point; instead of « this burn is at apoapsis » I was thinking of « this burn is half an anomalistic orbit after the preceding one ». The question is whether that is good enough, or whether we really want anchoring at M rather than previous + ΔM
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<discord->
lpg. — to me a "flight plan" necessarily means a series of step in which order is crucial. "this burn is at apoapsis" _must_ imply [, whatever that apoapsis has become after all prior maneuvers have completed] to be meaningful at all
<discord->
Stonesmile. — One simple example would be a hohmann transfer, having the Ap change to the *current* Ap because you delayed the first burn doesn't sound like what we want
<discord->
(experimentalshells?). — oh, and we cannot have two manœuvres executing simultaneously, i.e. if the apoapsis manœuvre starts at t = 120 and lasts 4 minutes, then it would cause some issues in the way of executing another manœuvre at t = 121
<discord->
lpg. — hm. I wonder if there _could_ exist useful cases for "burn thus much starting at this time. _while you're doing that_, also burn in this other direction for this much time"
<discord->
lpg. — hm. I wonder if there _could_ exist useful cases for "burn this much starting at this time. _while you're doing that_, also burn in this other direction for this much time" (edited)
<discord->
lpg. — (obviously the same result could be achieved by just breaking up the longer burn into multiple segments)
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<discord->
egg. — OK so to focus the discussion a bit, changing the order of manœuvres is not on the table, nor is overlapping manœuvres
<discord->
egg. — manœuvres becoming anomalous is fine (you can have that already)
<discord->
egg. — but my question is whether we actually need « this manœuvre is at apoapsis » (which would be absolute anchoring rather than just relative with different units), or whether « this manœuvre half an anomalistic revolution after the preceding one » does the job
<discord->
(experimentalshells?). — this becomes more complicated when I try to plot manœuvres at orbital nodes for inclination changes to geostationary
<discord->
(experimentalshells?). — do we fix the manœuvre to precisely when the next AN is, or something else
<discord->
Stonesmile. — You probably want a burn to begin approximately half the time before the point of interest, so maybe a button to set the time to a node from which you can fine tune? (I know this has already been suggested and the main issue was adding to the tax form)
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<discord->
Stonesmile. — You probably want a burn to begin approximately half the time before the point of interest, so maybe a button to set the time to a node from which you can fine tune? (I know this has already been suggested and the main issue was adding clutter to the tax form) (edited)
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<_whitenotifier-8975>
[Principia] pleroy opened pull request #2825: Reduction mod 2π - https://git.io/JLStn
<_whitenotifier-8975>
[Principia] pleroy opened pull request #2826: Mathematica output of DoublePrecision - https://git.io/JLStW
<discord->
lpg. — I'm struggling to find use cases for that _other_ than hohmann transfers
<_whitenotifier-8975>
[Principia] pleroy labeled pull request #2828: A HexLiteral for the IEEE754FloatingPoint package - https://git.io/JLSOt
<discord->
egg. — plane changes, except s/anomaly/argument of latitude/
<discord->
lpg. — I'm not seeing it. a plane change sounds like something else that wants absolute anchoring
<discord->
egg. — ah, you meant *that* as in relative anchoring by revolutions
<discord->
egg. — I thought you meant *that* as in anything described in my sentence
<discord->
lpg. — I meant "that" as in
<discord->
lpg. — > « this manœuvre half an anomalistic revolution after the preceding one »
<discord->
egg. — right
<discord->
egg. — in principle yes, and even Hohmann burns would want absolute anchoring in anomaly; the question is whether relative anchoring in the relevant element is good enough to fudge it without having all the UX & logic problems of absolute anchoring
<discord->
egg. — probably not
<discord->
lpg. — being limited to things that _have a "preceding one" seems very restrictive. hohmann transfers are the only thing that come to mind that involves 2 maneuvers with a well-defined "fraction of revolution" interval between them
<discord->
lpg. — being limited to things that _have_ a "preceding one" seems very restrictive. hohmann transfers are the only thing that come to mind that involves 2 maneuvers with a well-defined "fraction of revolution" interval between them (edited)
<discord->
egg. — OK, how about anchoring that is absolute mod 2π but relative in number of revolutions, e.g., « manœuvre #2 is at the apoapsis 5 rev. after manœuvre #1 »
<discord->
egg. — (I am mostly trying to avoid having to number revolutions absolutely)
<discord->
egg. — (and also trying to dodge the « out-of-order » situation obviously)
<discord->
lpg. — the distinction isn't clear to me (between what you propose and want to avoid)
<discord->
egg. — > manœuvre #2 is at the apoapsis 5 rev. after manœuvre #1
<discord->
egg. — so moving #1 forward will bump #2 from time to time,
<discord->
egg. — rather than
<discord->
egg. — > manœuvre #2 is at the apoapsis of the 57th revolution
<discord->
egg. — where moving #1 would have no effect on #2 until they invert and #2 becomes anomalous; but what does « the 57th revolution » mean ?
<discord->
lpg. — ahh. Relative number of revolutions sounds like the more useful option (ref. my "a flight plan necessarily means a series of steps")
<discord->
egg. — that is good, because it side-steps the annoyance of absolutely numbering revolutions :D
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<discord->
egg. — > ⟨pleroy⟩ [translated] those people [in the discord] seem to be doing something that I don't understand, which is to play with our mod
<raptop>
What are we supposed to do, use it to do simulations and write papers about what that means for solar system dynamics?
<discord->
Paculino (ŝi/ri/she/they). — Any ideas why it would be only sometimes?
<discord->
Paculino (ŝi/ri/she/they). — What is weird about that?
<discord->
Paculino (ŝi/ri/she/they). — raptop, I was going to use it for extra credit in physics (calculating the Lagrange point positions), but after spending a weekend in spreadsheets.... I learned that it was merely a joke
<raptop>
hah
<discord->
Paculino (ŝi/ri/she/they). — What does pleroy use the mod for? Or is perfecting it what he derives pleasure from now?
<discord->
Standecco. — rapotop: that's the intended use case, of course
<discord->
Standecco. — does the IRC bot handle message edits?
<discord->
Standecco. — raptop: that's the intended use case, of course (edited)
<raptop>
the bot sends the edited message again
<discord->
Standecco. — ah, smart
<discord->
Standecco. — the intended use case for the mod is catalyzing math and cat talk while trying to explain random people why you can't create a Principia light
<discord->
Standecco. — and while you're at it write a few papers on integration and orbit history storage
<discord->
Standecco. — and while you're at it write a few papers on numerical integration and orbit history storage (edited)
<discord->
Standecco. — (I'll now feel bad every time I edit a message because the IRC people are going to see 4 copies of almost the same message)
<raptop>
Also, practice at internationalization
<discord->
Standecco. — has principia been localized in cuneiform?
<raptop>
Not that I'm aware of, though egg has been working on a cuneiform IME
<discord->
Standecco. — literally unplayable
<discord->
Butcher. — I want principia light in cuneiform.
<raptop>
We regret to inform you that it involves a flat earth, and heavy objects fall faster than lighter ones
<discord->
lpg. — _finally_ we can play realistic ksp
<discord->
Paculino (ŝi/ri/she/they). — Well, heavier objects fall faster than lighter ones assuming they are the same size and shape and are falling in a fluid
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<discord->
egg. — beware what you wish for
<discord->
egg. — pleroy has never played KSP except to debug Principia
<egg|laptop|egg>
hmm, the bot does not mark replies to a post as such
<discord->
Skylar (She/Her). — I dont even know what that means lol
<egg|laptop|egg>
maybe I should check if there is a new version of the bot
<discord->
egg. — (that bit of cuneiform is *a-na* AN-*lar* *qí-bí-ma* *um-ma* NUNUZ, following th standard pattern of Babylonian letterheads, roughly « to Sky-lar, speak : thus says Egg »)
<discord->
egg. — (that bit of cuneiform is *a-na* ᶠAN-*lar* *qí-bí-ma* *um-ma* ᵐNUNUZ, following th standard pattern of Babylonian letterheads, roughly « to Sky-lar, speak : thus says Egg ») (edited)
<discord->
Paculino (ŝi/ri/she/they). — Has any Principia version used Cunneiform names?
<discord->
egg. — not yet
<discord->
egg. — (that bit of cuneiform is *a-na* ᶠAN-*lar* *qí-bí-ma* *um-ma* ᵐNUNUZ, following the standard pattern of Babylonian letterheads, roughly « to Sky-lar, speak : thus says Egg ») (edited)
<raptop>
It's not clear to me that we have babylonian mathematician names
<egg|laptop|egg>
that is indeed an issue
<egg|laptop|egg>
There appears to be someone called kidinnu
<egg|laptop|egg>
OK, that is good to know, it is a j release then
<raptop>
...given those hieroglyphics blocks, I'm disapointed that wikipedia only has transliterations of his name
<discord->
egg. — Unicode hieroglyphs have not been adopted all that much; a recent proposal deals with some truly advanced features and massively expands the character set, hopefully it is more successful
<discord->
egg. — Sumero-Akkadian cuneiform has comparatively been quite well adopted, but the 2014 update hasn’t really made it into real-world usage
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<discord->
Standecco. — the dynamics of how this mod came to be are hard to imagine