egg changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is Cardano. We currently target 1.2.2. <scott_manley> anyone that doubts the wisdom of retrograde bop needs to get the hell out | https://xkcd.com/323/
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<UmbralRaptor>
!win32
<Qboid>
Win32 is no longer supported. Please use the x64 build, available through !win64, or get a new bird.
<UmbralRaptor>
?
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<egg|zzz|egg>
!u ?
<Qboid>
U+1F985 EAGLE (?)
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<GH>
[Principia] pleroy closed pull request #1301: Use an integrator instance in Ephemeris::FlowWithFixedStep (master...InstanceInEphemeris) https://git.io/vSlI7
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<maccollo>
created the crashed into sun bug on an all stock install
<egg|zzz|egg>
maccollo: I may have fixed the inclination thing
<egg|zzz|egg>
maccollo: and maybe that fixes the crashed into the sun thing too, for all I know
<egg|zzz|egg>
we tend to lose vessels sometimes, which can't be a good thing
<maccollo>
it appears easier to do when you are leaving with more C3
<maccollo>
also, I noticed that the gradual downwarp when crossing that is in stock, is not happening with principia
<maccollo>
but
<egg|zzz|egg>
ah good
<maccollo>
it still attempts to downwarp to 1x the instant you cross
<egg|zzz|egg>
Augustus: the right ascension and declination are angles that describe a direction
<Augustus>
Yeah
<Augustus>
So what would I input there
<egg|zzz|egg>
angles
<egg|zzz|egg>
that describe the direction of the axis
<Augustus>
Ah
<Augustus>
So I can just leave that as is for Kerbin since I want an Earth-like axial tilt
<egg|zzz|egg>
these numbers are in the equatorial reference frame
<egg|zzz|egg>
so Earth isn't tilted
<egg|zzz|egg>
with respect to earth's equator
<Augustus>
wait what
<Augustus>
So to give Kerbin a 23.4 degree axial tilt, would I set RA to 23.4?
<egg|zzz|egg>
Earth is not tilted with respect to Earth
<egg|zzz|egg>
that would put its axis 23.4 degrees off the reference plane
<Augustus>
So that would be the right tilt
<egg|zzz|egg>
assuming you keep the rest of the KSP system unchanged, that would be quite a bit of tilt
<egg|zzz|egg>
90-23.4 degrees
<Augustus>
Ahhh
<Augustus>
So I would want to set it to 66 degrees?
<egg|zzz|egg>
I don't know, I can't count
<egg|zzz|egg>
;rpn 90 66 -
<kmath>
egg|zzz|egg: 24.0
<Augustus>
Well 66.6
<Augustus>
close enough
<Augustus>
And DEC is just the longitude of the tilt?
<egg|zzz|egg>
no it's the declination
<egg|zzz|egg>
were it the longitude, it would say longitude
<Augustus>
Does adjusting DEC change the tilt or no
<egg|zzz|egg>
it changes the direction of the axis
<egg|zzz|egg>
define "tilt"
<e_14159>
Might I recomment an astronomy book?
<e_14159>
s/ent/end
<Qboid>
e_14159 meant to say: Might I recommend an astronomy book?
<egg|zzz|egg>
it does not change the angle between the reference plane and the axis, but it may change the angle between the orbital plane and the axis
<Augustus>
Ah
<Augustus>
Okay so I'll just leave that alone
<egg|zzz|egg>
....
<egg|zzz|egg>
that would put all your axes in the same plane
<egg|zzz|egg>
which would be a bit of an odd coincidence
<Augustus>
So can I set it to some random number
<egg|zzz|egg>
you can do whatever you want
<Augustus>
Okay
<egg|zzz|egg>
you can also type "teabot" in there, but that will probably crash the game
<Augustus>
What is the reference instant
* e_14159
hands egg|zzz|egg a cup of tea.
<egg|zzz|egg>
it is an instant.
<egg|zzz|egg>
it is expressed as a Julian Date in TT or TDB
<Augustus>
Ah
<egg|zzz|egg>
we consider TT and TDB as equivalent.
<Augustus>
So in the stock game does that matter
<egg|zzz|egg>
it tells the game how to interpret the reference angle
<egg|zzz|egg>
the reference angle defines is rotation of the body at the reference instant
<egg|zzz|egg>
please refer to the WGCCRE report for details
<egg|zzz|egg>
it will explain better than I can without figures
<Augustus>
So it basically sets the local time at the reference instant
<Augustus>
I'm not going to go order a math textbook
<Augustus>
I just want to give Kerbin axial tilt in my 3.2x rescale
<egg|zzz|egg>
Augustus: please refer to figure 1 of the special report of the WGCCRE
<Augustus>
Oh, J2 doesn't matter since Kerbin is spherical
<Augustus>
okie
<Augustus>
just needs to be 0
<Augustus>
Now I just need to calculate the gravitational parameter and I'll be on my way
<egg|tea|egg>
you do not need to specify it if you're using a kopernicus-specified body
<egg|tea|egg>
we'll fetch the stock one
<egg|tea|egg>
not sure if you need the radii
<Augustus>
I have it 3.2x rescaled tho
<Augustus>
So the radius is 1920 km and gravity is 1.0
<egg|tea|egg>
you need the reference_radius if you specify j2
<egg|tea|egg>
if you don't give a j2, you probably don't need it
<Augustus>
ok
<Augustus>
Reference_radius is 1920 km tho right?
<egg|tea|egg>
so if you only want tilt, only the axis α and δ are needed
<egg|tea|egg>
Augustus: if you don't specify j2 you don't need to specify it
<egg|tea|egg>
so don't
<egg|tea|egg>
if you do specify a j2 you will need to specify it
<Augustus>
So just put // in front of both?
<Augustus>
egg
<Augustus>
Egg?
<Augustus>
Egg what happened
<Thomas>
He probably has better things to do than sitting in front of his computer 24/7
<Augustus>
Yeah I guess
<egg>
Augustus: tea happened
<egg>
which counts as a special case of what Thomas said
<egg>
Augustus: just *don't put them in*, why do you want to leave in commented-out stuff
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<Augustus>
Well
<Augustus>
KSP crashes at the space center
<Augustus>
so
<Augustus>
I did something wrong
<maccollo>
I'm gonna try to use a tool for orbiter to lauch to Mars and back on a specific trajectory
<Augustus>
Nice
<maccollo>
I know it works from Earth
<Augustus>
I need help calculating the gravitational parameter for something
<maccollo>
I think orbiter also models the axial tilt of the planets?
<Augustus>
well, calculating the mass
<Augustus>
not the grav parameter
<Augustus>
Tht's cool maccollo
<egg>
maccollo: probably? I mean not doing it sounds very kspish
<egg>
Augustus: the FATAL log will tell you what went wrong
<Augustus>
I didn't put the grav parameter in because I can't figure out the mass of the rescaled Kerbin
<egg>
Augustus: and you don't need to specify the gravitational parameter, I told you already if you want to just tilt, the only things you'll need are the axis ra and decl
<egg>
Augustus: you're using kopernicus for your custom planets right?
<egg>
Augustus: are you using the same method as RSS for the rings? because that works with our stuff
<Augustus>
No
<egg>
no to which question
<Augustus>
The planets aren't custom, I'm just rescaling them and moving some stuff around
<Augustus>
but yeah Kopernicus
<Augustus>
I'm trying to make a balanced realistic solar system where stock ships can still be used
<egg>
anyway
<egg>
back to working on principia
<Thomas>
Augustus: Rings are attached to the scaled space, so if the scaled space is rotated the rings are rotated
<egg>
Thomas: ok, so then that should work?
<Augustus>
rings weren't rotated with Sarnus
<Augustus>
IDC about the outer planets being tilted anyway
<egg>
Thomas: well I mean I *know* it works with RSS, so I'm not sure what Augustus is doing but it involves screwing *something* up
<Augustus>
just want Kerbin and tilted
<Augustus>
*duna
<egg>
ok, you're failing to understand
<Augustus>
and I need to tilt Duna's moons
<egg>
if you tilt *anything*, the whole universe needs to tilt when you're close to that thing
<Augustus>
yeah IK
<egg>
including the outer planets
<egg>
so you *do* care about that
<Thomas>
egg: Only something?
<Augustus>
I'm just testing Kerbin and Duna right now
<Augustus>
I made a stripped-down install that loads faster
* egg|reviewing_code|egg
sort of trying to get some work done on principia right now
<Augustus>
Uhh I just noticed a weird thing w/ duna
<Augustus>
The axis is always pointed 90 degrees away from the sun
<Augustus>
Duna has no seasons
<Augustus>
Guys?
<e_14159>
Augustus: Please note that it is often considered impolite to assume people answering all questions right away. All of us do have lives outside of IRC.
<Augustus>
ik
<Augustus>
sorry
<Augustus>
The axis of Duna is always pointed 90 degrees from the Sun.
<Augustus>
that's not correct
<Augustus>
Oh wait
<Augustus>
no its not
<Augustus>
nvm
<Augustus>
uhh
<Augustus>
Kerbin aint tilted
<maccollo>
kerbin will never appear tilted
<maccollo>
did you check from a different gravity well?
<Augustus>
What do you mean
<GH>
[Principia] eggrobin commented on issue #1304: I am confused by the comments at lines 279 and 113: if they are true, do we fail a check if an integration with last_step_is_exact produces only one (truncated) point? Otherwise, this is really the last state, possibly truncated, but it is only resumable if it does not result from a truncation. I don't think we should be dealing with `final_state` if last_step_is_exact. https://git.io/vSlxt
<Augustus>
Like, the sun isn't hitting it from an angle either tho
<Augustus>
maccollo
<Augustus>
The sun isn't hitting it from an angle either
<maccollo>
hm
<egg|reviewing_code|egg>
well if nothing at all is tilted then it may indicate we're not seeing your config
<Augustus>
Duna and Neidon are tilted (I added Neidon's part back in)
<Augustus>
Kerbin isn't
<maccollo>
are their orbits tilted?
<Augustus>
No
<Augustus>
the solar system appears flat
<Augustus>
(well, except for Moho, Dres and Plock)
<egg|reviewing_code|egg>
Augustus: oh so that would be because I got confused between right ascension and declination
<egg|reviewing_code|egg>
Augustus: in the explanation above, swap the two
<egg|reviewing_code|egg>
Augustus: and this is why you should read the WGCCRE paper, which gets things right, rather than ask me, for I say stupid things
<Augustus>
Oh okay
<egg|reviewing_code|egg>
with a declination of 90 deg the axis is perpendicular to the reference plane
<Augustus>
Ah
<Augustus>
That explains the wonky Jool and whatnot
<Augustus>
THERE WE GO
<Augustus>
It's beautiful!
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<Augustus>
Uhh
<Augustus>
How do I fix the rings
<Augustus>
Sarnus is messed up
<Augustus>
Sarnus' rings are tilted even tho the planet itself isn't