Ultimate space simulation software

  • 1
  • 6
  • 7
  • 8
  • 9
  • 10
 
User avatar
SpaceEngineer
Author of SpaceEngine
Author of SpaceEngine
Posts: 1125
Joined: 17 May 2016 22:16
Location: Saint-Petersburg
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

12 Oct 2018 07:02

Thanks for update guys! I integrated the whole catalog, removing "Remove" objects manually from other catalog files. It will be in the next Steam update. Since now, please also add new objects to a separate sc file as "update for 0.990 patch 14", so I could track them and add manually.

Some errors (probably?)

Fixed Lempo discovery date, added alternate designations to all its components
Fixed discovery date of 2007 OR10 and its satellite, I also moved them to SolarSys.sc
Fixed many missing-slash names like this: "S2007 (1453) 1" -> "S|2007 (1453) 1"
Fixed a lot of syntax errors and missing parameters (for example, (5112) Kusaji have missing Mass value, a lot of asteroids have empty DiscMethod)
Asteroid "Siding Spring /(2343) Siding Spring" (with space before /) is renamed to "Siding Spring$AS/(2343) Siding Spring" ($AS are non-printable characters). Comet "Siding Spring/C|2013 A1 (Siding Spring)" is also renamed to Comet "Siding Spring$CO/C|2013 A1 (Siding Spring)".

I also added a code which reduces model radius of small asteroids, which are too "bumpy" and thus looks too large (significantly larger than selection pointer "radius"). Now small asteroids are more or less fit into provided mean radius. They became more round though...
 
User avatar
SpaceEngineer
Author of SpaceEngine
Author of SpaceEngine
Posts: 1125
Joined: 17 May 2016 22:16
Location: Saint-Petersburg
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

12 Oct 2018 07:04

I use SE 0.980_e.
But I meant for the asteroid '3122 Florence (1981 ET3)'. That's probably not in the ephemeris database at all.
And if it should be in, I do not know its parameters. (AnalyticModel, RotationModel)
Of course no, I didn't implemented ephemerides for asteroids.
 
User avatar
Mosfet
Star Engineer
Star Engineer
Topic Author
Posts: 1770
Joined: 24 Oct 2016 11:34
Location: Italy
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

12 Oct 2018 11:22

a separate sc file as "update for 0.990 patch 14"
Sure will do.
As you probably suspected, since the catalog is intended to be compatible also with 0980, that's the reason for missing slashes. Same reason for that space for (2343) Siding Spring, it's a "trick" in order to separate comet and asteroid in Object Finder in a pleasing way, without changing official definitions. For patch 14+ updates we'll use correct syntax (thanks, notepad++ macros! ;)) as well as the special character $ if needed.

The rest slipped through my checkings. v_v
I also added a code which reduces model radius of small asteroids
That was indeed a visual discrepancy, great! We'll see how it goes.
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |
 
User avatar
SpaceEngineer
Author of SpaceEngine
Author of SpaceEngine
Posts: 1125
Joined: 17 May 2016 22:16
Location: Saint-Petersburg
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

16 Oct 2018 03:08

Updated asteroid (809) Lundia: mass ratio and shape parameters from this article. This will work only in 0.990, because it supports tri-axial ellipsoid shape.

For 0.990, if you find dimensions data for asteroids, you can use them in catalog script. Note that dimensions are usually twice larger than radius: they are "diameters". In the Dimensions (X, Y, Z) parameter, X component is along orbital path, Y is rotation axis, Z is in direction of second companion. Usually Y is smallest, Z is largest.

To make asteroid shape more "round", reduce venusMagn: it is amplitude of the global "random shape" of the asteroid (and venusFreq is its frequency). This will work in the next patch (build 15).
Asteroid "Lundia/(809) Lundia"
{
	ParentBody	"Lundia system"
	Class		"Asteroid"

	DiscMethod	   "Imaging"
	DiscDate	   "1915.08.11"

	Dimensions	(6.6, 6.4, 7.8)	// km
	Mass		7.0588e-11		// Mearth, mass ratio 0.7
	TidalLocked true

	Surface
	{
		venusMagn 0.0	// make shape more round
	}

	Orbit
	{
		SemiMajorAxisKm 6.5059	// separation 15.8 km, mass ratio 0.7
		Period          0.001759
		Eccentricity    0
		Inclination     0
		AscendingNode   0
		ArgOfPericenter 180
		MeanAnomaly     0
		RefPlane        "Equator"
	}
}

Asteroid "S|2005 (809) 1"
{
	ParentBody	"Lundia system"
	Class		"Asteroid"

	DiscDate   "2005.09.18"
	DiscMethod "OrbitLight"

	Dimensions	(5.8, 5.6, 7.0)	// km
	Mass		4.9412e-11 		// Mearth, mass ratio 0.7
	TidalLocked true
	
	Surface
	{
		venusMagn 0.0	// make shape more round
	}

	Orbit
	{
		SemiMajorAxisKm 9.2941	// separation 15.8 km
		Period          0.001759
		Eccentricity    0
		Inclination     0
		AscendingNode   0
		ArgOfPericenter 0
		MeanAnomaly     0
		RefPlane       "Equator"
	}
}
 
User avatar
Mosfet
Star Engineer
Star Engineer
Topic Author
Posts: 1770
Joined: 24 Oct 2016 11:34
Location: Italy
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

10 Dec 2018 12:32

New additions:
(20882) 2000 VH57
(6100) Kunitomoikkansai
(2178) Kazakhstania
(100015) 1989 SR7

File updates are available in OP.
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |
 
User avatar
SpaceEngineer
Author of SpaceEngine
Author of SpaceEngine
Posts: 1125
Joined: 17 May 2016 22:16
Location: Saint-Petersburg
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

10 Dec 2018 21:43

Thanks, integrated.
 
User avatar
Silicon
Space Tourist
Space Tourist
Posts: 32
Joined: 29 Jul 2017 13:41

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

11 Dec 2018 11:57

Hey Mosfet. I have been looking at the asteroids I have submitted and noticed that for most of them I gave incorrect axial-tilt data. I just thought you should know. Do you want me to remove the axial tilt data in the ones I provided?
 
User avatar
Mosfet
Star Engineer
Star Engineer
Topic Author
Posts: 1770
Joined: 24 Oct 2016 11:34
Location: Italy
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

11 Dec 2018 12:18

Do you want me to remove the axial tilt data in the ones I provided?
Hey Silicon. Shouldn't be a big issue, you could just help me with the list of asteroids you provided, and I'll check them.
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |
 
User avatar
Silicon
Space Tourist
Space Tourist
Posts: 32
Joined: 29 Jul 2017 13:41

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

12 Dec 2018 16:30

Sure, I'll give you the list of asteroids with tilt data. Tilt data is the only thing I provided incorrectly, so I wont bother posting the ones that have no tilt data.
► Show Spoiler
The only thing incorrect about these objects is their axial-tilt data. Because back when I made them I didn't know how The Johnston Archive organized axial-tilt. I thought it was relative to the ecliptic but it's actually the direction of the North Pole.

Also for two objects, 2002 VT130 and 5674 Wolff, they are both objects with a barycenter and no axial-tilt data. Because SpaceEngine will not procedurally generate axial-tilts for binary objects, how should these objects be handled? Should they be given tilts of 0 (0 tilt binary objects look weird) or a random tilt?

And as an apology letter, here's an asteroid. (4435) Holt.
► Show Spoiler
Last edited by Silicon on 13 Dec 2018 18:44, edited 1 time in total.
 
User avatar
SpaceEngineer
Author of SpaceEngine
Author of SpaceEngine
Posts: 1125
Joined: 17 May 2016 22:16
Location: Saint-Petersburg
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

12 Dec 2018 20:57

Modern catalog uses IAU axial tilt notation, which describes celestial coordinates of the north pole while looking from the body. SE supports this as a RotationModel tag:
	RotationModel	"IAU"
	{
		Epoch		2451545		// J2000
		PoleRA      	269.9949	// degrees
		PoleRARate  	0.0031		// degrees/century (precession)
		PoleDec     	66.5392		// degrees
		PoleDecRate 	0.0130		// degrees/century (precession)
		PrimeMeridian	38.3213		// degrees
		RotationRate	13.17635815	// degrees/day (inverse of rotation period)
		RotationAccel	-0.0018677	// degrees/century^2 (deceleration of rotation period)
}
If precession and deceleration of rotation period data is missing, simply skip those parameters. Position of PrimeMeridian has little sense for procedural model, but if catalog provides this data, better to grab (can be used in future with a real model).

For binary asteriods, you may simple add TidalLocked true (to the main asteroid's code, no inside the RotationModel tag) to make it tidally-locked to the parent.
 
User avatar
Silicon
Space Tourist
Space Tourist
Posts: 32
Joined: 29 Jul 2017 13:41

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

14 Dec 2018 19:46

(16974) Iphthime, A binary Jupiter trojan.
► Show Spoiler
 
User avatar
Mosfet
Star Engineer
Star Engineer
Topic Author
Posts: 1770
Joined: 24 Oct 2016 11:34
Location: Italy
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

17 Dec 2018 17:54

Thanks Silicon, are you sure about epoch? that julian date apparently puts those orbital elements in year 4161773 :)
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |
 
User avatar
Silicon
Space Tourist
Space Tourist
Posts: 32
Joined: 29 Jul 2017 13:41

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

18 Dec 2018 09:05

No actually. I don't know how to convert dates to epoch, I just put the date in wolfram alpha and had it convert for me.

The dates should be September 4, 2017 for Holt and March 23, 2018 for Iphthime.
 
User avatar
Mosfet
Star Engineer
Star Engineer
Topic Author
Posts: 1770
Joined: 24 Oct 2016 11:34
Location: Italy
Contact:

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

18 Dec 2018 14:24

Oh, Ok then. Epoch is expressed in Julian Days (Julian Date), which is the number of days counting from noon of January 1, 4713 BC. There are several converters online. In Wolfram Alpha, if your input is "March 23, 2018", you should get

Input interpretation:
Friday, March 23, 2018

If you click on "More formats/calendars" to the right you'll find the corresponding Julian Day Number, in this case 2458201.

Counting the date from midnight, it should be 2458200.5, probably Wolfram Alpha is rounding the decimal.
"Time is illusion. Lunchtime doubly so". Douglas N. Adams
| My mods: http://forum.spaceengine.org/viewtopic.php?f=3&t=80 | My specs: Asus x555ub - cpu i5-6200u, ram 12gb, gpu nvidia geforce 940m 2gb vram |
 
User avatar
Silicon
Space Tourist
Space Tourist
Posts: 32
Joined: 29 Jul 2017 13:41

COMMUNITY ADDON - Double/Multiple Asteroids fixes for SE

26 Dec 2018 11:03

Here are 3 more asteroids. (31450) Stevepreston, (34706) 2001 OP83, and (35107) 1991 VH.
► Show Spoiler
  • 1
  • 6
  • 7
  • 8
  • 9
  • 10

Who is online

Users browsing this forum: Bing [Bot] and 2 guests