raptop changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is Galileo. We currently target 1.5.1, 1.6.1, 1.7.x, 1.8.1, and 1.9.1. <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
bees has quit [Ping timeout: 189 seconds]
bees has joined #principia
<discord-_>
Kerbinator. — 🤔
<discord-_>
Kerbinator. — Why not 28deg, what's the reference 🤔\
<discord-_>
Kerbinator. — Why not 28deg, what's the reference 🤔 (edited)
<discord-_>
lpg. — the moon's inclination wobbles between ~19 and ~28 in principia, as it does in the real world
<discord-_>
egg. — @Kerbinator the reference plane here is the equator of the Earth
<discord-_>
Kerbinator. — ?
<discord-_>
Kerbinator. — Xichang and Cape Carnival is best for shooting a Moon transfer
<discord-_>
Kerbinator. — both 28deg latitude @egg
<discord-_>
Kerbinator. — Ouch so stock is max (28deg?)
<discord-_>
Kerbinator. — With patched conics, just use XiChang is okay
<discord-_>
Kerbinator. — With patched conics, just use XiChang is okay (28d latitude, 90 HDG with only smart A.S.S.) (edited)
<discord-_>
egg. — the inclination of the orbital plane of the moon with respect to the orbital plane of the earth (the ecliptic) is roughly constant, but the orbital plane of the moon rotates with respect to the ecliptic (nodal precession), so the inclination with respect to the *equator* (which is inclined with respect to the ecliptic by axial tilt) varies between tilt+inclination with respect to the ecliptic and til
<discord-_>
egg. — tilt = 23°.5, inclination with respect to the equator = 5°, so between 18°.5 and 28°.5
<discord-_>
egg. — tilt = 23°.5, inclination with respect to the ecliptic = 5°, so between 18°.5 and 28°.5 (edited)
egg|anbo|egg has quit [Remote host closed the connection]
<discord-_>
Indiantechkid. — Hey, I don't have principia, but can someone explain these rendezvous graphs? I know its a different plotting frame, but Its hard to understand. Thanks!
<discord-_>
scimas. — My guess would be radial distance on the vertical axis and angular on the horizontal axis? Or something like that..
<discord-_>
egg. — yeah the vertical is the vertical, and the horizontal is the horizontal, and the ISS is fixed at the origin
<discord-_>
egg. — so +r̄ is down, wherever you are, and +v̄ is horizontally along the orbit of the ISS
<discord-_>
egg. — this is again just the same thing as the target LVLH frame in Principia, except there the v̄ axis would be a circle
<discord-_>
Indiantechkid. — how is rendezvous done in real life? In ksp, we just do a hohmann transfer.
<discord-_>
egg. — > I don't have principia, but can someone explain
<discord-_>
egg. — So the Principia LVLH frame (this thing you are looking at in the figure) is one of the things that people seem to find most intuitive about Principia, so I guess my answer here would be that you could try it out to get an intuitive understanding of what this reference frame means
<discord-_>
Indiantechkid. — so R bar approach is approaching from Radial direction, but H bar is something where they do a hop
<discord-_>
egg. — there is no h bar
<discord-_>
Indiantechkid. — orbital motion is confusing without visuals
<discord-_>
egg. — this is a visual
<discord-_>
Indiantechkid. — wait what?
<discord-_>
egg. — you are looking at the orbit
<discord-_>
Indiantechkid. — oh sorry vbar not hbar
<discord-_>
egg. — you are looking at the orbit in a way that is just as meaningful as (and in the context of a rendez-vous, more useful than) ECI
<discord-_>
Indiantechkid. — oh. Interesting
<discord-_>
Indiantechkid. — so you change plotting frame for different things?
<discord-_>
egg. — yes, that is how you use Principia
<discord-_>
egg. — and that is what you do in real life too
<discord-_>
egg. — and this is (behind the scenes) what happens in stock even
<discord-_>
egg. — you don't look at your orbit around Kerbin as a trajectory around the Sun
<discord-_>
egg. — because that would be extremely useless
<discord-_>
Myshiko. — Well, it takes a university education and post-grad school to remove dogmas installed at kindergarten and elementary school. So, no wonder.
<discord-_>
Butcher. — But egg, all my planets have gone crazy "lol".
<discord-_>
Damien. — @egg you could see the astronauts on the recent dragon-ISS launch using something that looked a lot like the LVLH frame on their displays
<discord-_>
Damien. — was pretty cool to see
<discord-_>
Damien. — there's screenshots on here somewhere
<discord-_>
egg. — yeah the LVLH terminology and the idea for that frame does not come from the void, it is what people use
<discord-_>
egg. — there is a document listing the ISS frames somewhere
<discord-_>
egg. — iirc the Russians have a different axis convention
<discord-_>
Damien. — you mean you didn't invent the frames used in principia that NASA then stole? I'm disappointed egg
<discord-_>
egg. — right so ОСК is the RU counterpart to LO (aka LVLH), but Yоск=-Zlo, Zоск=Ylo (they agree on Xоск=Xlo, since they are thankfully both right-handed, this is a saner world than KSP)
<discord-_>
egg. — similar story for XPOP vs. РСО
<discord-_>
egg. — (though the axis conventions are differently different)
egg|cell|egg has quit [Ping timeout: 204 seconds]
<discord-_>
Butcher. — Why is right handed more sane than left?
<discord-_>
egg. — well, it is more common; the insanity comes in mixing the two
<discord-_>
Butcher. — LEft handed system is my brain's default, too much time working with LH graphics APIs.
<discord-_>
Butcher. — Left handed system is my brain's default, too much time working with LH graphics APIs. (edited)
<discord-_>
egg. — because some things don’t transform like other things when you change handedness
<discord-_>
egg. — bivectors (things like angular velocities, torques, angular momenta, etc.) get an extra sign when going through the looking glass
<discord-_>
Butcher. — I suppose RHS is more logical from a background of architechture.
<discord-_>
egg. — so you need to do bookkeeping to make sure you remember which kind of multivector you deal with
<discord-_>
egg. — there is nothing wrong with LHS intrinsically, except when it gets mixed with RHS
<discord-_>
egg. — Principia comes with a massive amount of typing trickery to make sure that we know when something is a vector or a bivector
<discord-_>
Butcher. — PRincipia's typing shenanigans are quite something.
<discord-_>
egg. — just like there is nothing wrong in working with, say, metre-tonne-second or centimetre-gram-second
<discord-_>
egg. — but if you start mixing CGS, MTS, and MKS, you definitely want to be very careful at the edges
<discord-_>
egg. — (KSP is mostly MTS)
<discord-_>
Butcher. — Furlong-firkin-fortnight?
<discord-_>
Butcher. — KSPO being MTS but a lot of RO being SI can be awkward at times.
<discord-_>
egg. — yup
<discord-_>
Butcher. — KSP# being MTS but a lot of RO being SI can be awkward at times. (edited)
<discord-_>
egg. — same with LHS but a lot being RHS
<discord-_>
egg. — (KSP has both in different places)
<discord-_>
Butcher. — Why would you do that?
* discord-_
egg. — points at the /topic_
<discord-_>
Butcher. — I do recall working on a game with both row and colum major matrix classes once.
<discord-_>
egg. — (also, the game industry, I suppose,)
<discord-_>
Butcher. — WEll, yes.
<discord-_>
Butcher. — Well, yes. (edited)
<discord-_>
Butcher. — The column major one was fun because the author didn;t understand homogenous co-ordinate systems, so just split out a 4x4 matrix into a 3x3 and a 1x3.
<discord-_>
Butcher. — (and hoped everything was affine).
<discord-_>
egg. — @Butcher also this has the flight plan rebase button, should you want to try that out
egg|cell|egg has quit [Ping timeout: 202 seconds]
Blu3wolf has quit [Quit: Konversation terminated!]
<discord-_>
Butcher. — Seems stable so far.
egg|cell|egg has joined #principia
Raidernick_ has quit [Read error: Connection reset by peer]
Raidernick has joined #principia
egg|cell|egg has quit [Ping timeout: 198 seconds]
Jesin has quit [Quit: Leaving]
<egg|anbo|egg__>
whee
Rokker has joined #principia
Jesin has joined #principia
<discord-_>
lamont. — egg: i'm definitely writing my own right handed vector class one way or another
<discord-_>
lamont. — need matrix3x3 with doubles that is right handed as well along with quats
<discord-_>
lamont. — right handed angles
<discord-_>
lamont. — euler angle APIs that let you specify what your euler angles actually are
<discord-_>
lamont. — it'll be beautiful
<discord-_>
egg. — @lamont are you doing physical quantities as well? :D
<discord-_>
DRVeyl. — Unity.mathematics ?
<discord-_>
lamont. — i think i've convinced myself that the only advantage of vectors as structs is garbage collection and i need to embrace classes and do memory pooling and correctly dispose of my vectors
<discord-_>
lamont. — if they are classes then they can be subclassed and they can be strongly typed and can be extended to include reference frames, etc
<_whitenotifier-d13c>
[Principia] eggrobin pushed 3 commits to master [+0/-0/±8] https://git.io/JJqHf
<_whitenotifier-d13c>
[Principia] eggrobin 98ae23b - NO leap second will be introduced at the end of December 2020.
<discord-_>
Diego_. — hi! is there any way of disabling the persistent rotation? it's really painful for some of the manned duration contracts... Thanks!
<discord-_>
Kirk. — You can set it to hold a relative angle?
<discord-_>
Kirk. — Why is it a problem?
<discord-_>
Myshiko. — Manned duration? Never was a problem for me? What’s wrong?
<discord-_>
Myshiko. — Manned duration? Never was a problem for me! What’s wrong? (edited)
<discord-_>
Myshiko. — Also, PersistentRotation mod should not be installed with Principia, as Principia handles craft rotation itself (and very well).