#principia on 2018-08-24 — irc logs at esper.irclog.whitequark.org

2018-08-12 00:58 UmbralRaptor changed the topic of #principia to: READ THE FAQ: http://goo.gl/gMZF9H; The current version is Desargues. We currently target 1.3.1, and 1.4.x. <scott_manley> anyone that doubts the wisdom of retrograde bop needs to get the hell out | https://xkcd.com/323/

00:00 NolanSyKinsley has quit [Remote host closed the connection]

00:03 NolanSyKinsley has joined #principia

00:23 NolanSyKinsley has quit [Remote host closed the connection]

00:33 <Qboid> 0d 3h 0m 0s left to event #27: 9/Telstar 18 [at 2018-08-24 03:33:00]. Say '!kountdown 27' for details

01:01 egg|laptop|egg has quit [Ping timeout: 190 seconds]

01:33 <Qboid> 0d 2h 0m 0s left to event #27: 9/Telstar 18 [at 2018-08-24 03:33:00]. Say '!kountdown 27' for details

02:27 NolanSyKinsley has joined #principia

02:33 <Qboid> 0d 1h 0m 0s left to event #27: 9/Telstar 18 [at 2018-08-24 03:33:00]. Say '!kountdown 27' for details

03:03 <Qboid> 0d 0h 30m 0s left to event #27: 9/Telstar 18 [at 2018-08-24 03:33:00]. Say '!kountdown 27' for details

03:05 NolanSyKinsley has quit [Ping timeout: 183 seconds]

03:08 NolanSyKinsley has joined #principia

03:23 <Qboid> 0d 0h 10m 0s left to event #27: 9/Telstar 18 [at 2018-08-24 03:33:00]. Say '!kountdown 27' for details

03:30 <Qboid> 0d 0h 2m 30s left to event #27: 9/Telstar 18 [at 2018-08-24 03:33:00]. Say '!kountdown 27' for details

03:33 <Qboid> 0d 0h 0m 0s left to event #27: 9/Telstar 18 [at 2018-08-24 03:33:00]. Say '!kountdown 27' for details

04:02 Mike` has quit [Ping timeout: 190 seconds]

04:08 Mike` has joined #principia

04:51 NolanSyKinsley has quit [Remote host closed the connection]

08:07 ferram4_ has quit [Read error: Connection reset by peer]

08:22 ferram4 has joined #principia

09:19 egg|laptop|egg has joined #principia

10:40 egg|laptop|egg has quit [Ping timeout: 190 seconds]

10:55 egg|laptop|egg has joined #principia

11:15 egg|laptop|egg has quit [Ping timeout: 190 seconds]

14:13 egg|laptop|egg has joined #principia

14:30 NolanSyKinsley has joined #principia

14:31 egg|laptop|egg has quit [Ping timeout: 183 seconds]

14:37 egg|phone|egg has joined #principia

14:39 egg|cell|egg has joined #principia

14:42 egg|phone|egg has quit [Ping timeout: 183 seconds]

15:25 egg|laptop|egg has joined #principia

15:36 NolanSyKinsley has quit [Remote host closed the connection]

15:36 NolanSyKinsley has joined #principia

16:07 NolanSyKinsley has quit [Remote host closed the connection]

16:07 NolanSyKinsley has joined #principia

16:32 pizzaoverhead has joined #principia

16:43 egg|cell|egg has quit [Ping timeout: 183 seconds]

16:46 egg|phone|egg has joined #principia

16:48 NolanSyKinsley has quit [Remote host closed the connection]

16:49 NolanSyKinsley has joined #principia

17:07 NolanSyKinsley has quit [Read error: Connection reset by peer]

17:08 NolanSyKinsley has joined #principia

17:08 NolanSyKinsley has quit [Remote host closed the connection]

17:09 NolanSyKinsley has joined #principia

17:09 NolanSyKinsley has quit [Remote host closed the connection]

17:13 NolanSyKinsley has joined #principia

17:15 awang has quit [Quit: leaving]

17:36 egg|phone|egg has quit [Ping timeout: 190 seconds]

17:42 Jesin has quit [Quit: Leaving]

17:47 Jesin has joined #principia

17:54 egg|laptop|egg has quit [Ping timeout: 190 seconds]

18:27 Jesin has quit [Quit: Leaving]

18:42 egg|phone|egg has joined #principia

18:44 egg|cell|egg has joined #principia

18:47 egg|phone|egg has quit [Ping timeout: 190 seconds]

19:02 GregroxMun has joined #principia

19:02 <GregroxMun> hey y'all

19:02 <GregroxMun> what's up?

19:02 <GregroxMun> I need to make Mesbin oblate

19:02 <GregroxMun> https://i.imgur.com/GVohDJC.png

19:02 <GregroxMun> like with j2

19:03 <GregroxMun> how do I calculate this j2?

19:03 <GregroxMun> egg?

19:03 <GregroxMun> umbralRaptor?

19:03 <GregroxMun> egg|anbo|egg egg|cell|egg

19:04 NolanSyKinsley has quit [Remote host closed the connection]

19:04 NolanSyKinsley has joined #principia

19:19 awang has joined #principia

19:21 egg|laptop|egg has joined #principia

19:44 egg|laptop|egg has quit [Ping timeout: 190 seconds]

19:45 egg|cell|egg has quit [Ping timeout: 190 seconds]

19:45 egg|phone|egg has joined #principia

19:48 egg|phone|egg has quit [Ping timeout: 190 seconds]

19:48 egg|phone|egg has joined #principia

19:52 egg|phone|egg has quit [Ping timeout: 190 seconds]

20:27 egg|phone|egg has joined #principia

20:27 <egg|phone|egg> And anyway since planets are not homogeneous the shape does not give the gravitational oblateness

20:28 egg|cell|egg has joined #principia

20:28 egg|phone|egg has quit [Read error: Connection reset by peer]

20:30 <GregroxMun> I think only part of your message went through

20:30 <GregroxMun> I only see

20:30 <GregroxMun> "And anyway since planets are not homogeneous the shape does not give the gravitational oblateness "

20:31 <GregroxMun> which looks like the continuation of a train of thought with no beginning

20:31 <GregroxMun> err...

20:31 <GregroxMun> no...

20:31 <GregroxMun> locomotive

20:32 <GregroxMun> egg|phone|egg

20:32 <GregroxMun> egg|cell|egg

20:53 egg|laptop|egg has joined #principia

20:54 <egg|anbo|egg> GregroxMun: yeah

21:02 <egg|laptop|egg> GregroxMun: the answer is I'm not sure; you can try to find formulae for a homogeneous body to get J2 from the shape of the ellipsoid, but planets are not homogeneous so that's pointless

21:02 <GregroxMun> well it's not so pointless as to be useless

21:02 <GregroxMun> it would at least give me a basis to use

21:02 <egg|laptop|egg> GregroxMun: the easy answer is to take a planet with known J2 that resembles what you want, and use the same J2

21:02 <GregroxMun> maybe I could tweak it from there

21:02 <egg|laptop|egg> not really, it's likely massively off.

21:03 <GregroxMun> Mesbin is not like o, it is like ()

21:03 <GregroxMun> it is really oblate

21:03 <GregroxMun> like twice as wide as it is tall

21:04 <GregroxMun> there are no known planets with known j2

21:04 <GregroxMun> that are like Mesbin

21:04 <egg|laptop|egg> Vesta

21:04 <GregroxMun> not quite good enough, but it's a start

21:04 <GregroxMun> https://i.imgur.com/GVohDJC.png

21:04 <GregroxMun> this is a pic of the planet

21:05 <egg|laptop|egg> vesta will be close enough

21:05 <GregroxMun> ok

21:05 <egg|laptop|egg> https://github.com/mockingbirdnest/Principia/blob/master/astronomy/sol_gravity_model.proto.txt#L362-L378

21:08 <GregroxMun> thanks

21:11 <GregroxMun> I don't remember if my current implementation of Whirlgig World is gravitationally stable...

21:11 <GregroxMun> I know I did implement an integrator step size patch to deal with a few extreme moons

21:13 <GregroxMun> also I still can't have my default hyberbolic object :v

21:17 <GregroxMun> https://i.imgur.com/MYxZeVk.png

21:17 <GregroxMun> also without barycentric orbit rendering I have no clue if this is stable or not :v

21:17 <GregroxMun> it's based directly upon the Pluto/Charon system

21:17 <GregroxMun> but with a gas giant :D

21:17 <GregroxMun> well, two

21:20 <GregroxMun> focussing on the moons individually they look fine, so it's probably fine!

21:21 <GregroxMun> https://i.imgur.com/5kywkmM.png

21:21 <GregroxMun> this is pretty nice actually

21:21 <GregroxMun> that's a saturn mass planet with a close in earth mass ice moon and an Io analogue in yellow

21:22 <GregroxMun> not too surprising given that Laythe and Tylo can coexist eventually once Vall's out of the way

21:27 <egg|laptop|egg> GregroxMun also without barycentric orbit rendering I have no clue if this is stable or not :v << install a timewarp mod and wait a while :D

21:41 <GregroxMun> ^^ make barycentric orbit rendering :D

21:41 <GregroxMun> ^ ^, not ^^

21:41 <GregroxMun> on kiwiirc at least ^^ is turned into an emoticon

21:41 <GregroxMun> anyway

21:41 <GregroxMun> I have a few really cool binary ideas that pretty much need barycentric orbit rendering to work

21:42 <GregroxMun> or else they're unplayable

23:05 NolanSyKinsley has quit [Remote host closed the connection]

23:05 NolanSyKinsley has joined #principia

23:08 awang has quit [Ping timeout: 190 seconds]

23:13 NolanSyKinsley has quit [Remote host closed the connection]

23:13 NolanSyKinsley has joined #principia

23:17 NolanSyKinsley has quit [Remote host closed the connection]

23:18 NolanSyKinsley has joined #principia

23:18 NolanSyKinsley has quit [Remote host closed the connection]

23:19 NolanSyKinsley has joined #principia

23:21 egg|laptop|egg has quit [Ping timeout: 190 seconds]

23:24 egg|laptop|egg has joined #principia

23:37 egg|laptop|egg has quit [Ping timeout: 180 seconds]

23:53 egg|laptop|egg has joined #principia