Posts by granthutchison

by granthutchison
03.10.2012, 15:15
Forum: Physics and Astronomy
Topic: 2 planets found orbiting different stars in Beehive Cluster
Replies: 1
Views: 1563

Re: 2 planets found orbiting different stars in Beehive Clus

They're already present in the latest versions of extrasolar.ssc and extrasolar.stc on the trunk of the SVN tree, update 5214. :)
http://celestia.svn.sourceforge.net/vie ... stia/data/

Grant
by granthutchison
02.09.2012, 20:06
Forum: Physics and Astronomy
Topic: Group of close orbiting neutron stars and event horizon
Replies: 1
Views: 1843

Re: Group of close orbiting neutron stars and event horizon

Trouble is, if they're in a stable orbit, they've got to be farther apart than the size of the black hole that would be created from their combined masses - so the density of any such stable system is less than the critical black hole "density" mentioned in your question. And if you move t...
by granthutchison
02.09.2012, 17:34
Forum: Celestia Users
Topic: Belt of Venus and weather
Replies: 5
Views: 3949

Re: Belt of Venus and weather

Yes, the refraction of light at sunrise and sunset. Sorry about that :oops: Don't worry, dermeisterike , you got the name exactly right. I fear john Van Vliet may have fallen foul of Wikipedia 's ongoing effort to ensure everyone on the planet has access to the same misinformation. ;) The arc of co...
by granthutchison
01.10.2011, 00:10
Forum: Add-on development
Topic: CoRoT Exoplanets Catalogue
Replies: 31
Views: 11565

Re: CoRoT Exoplanets Catalogue

Deepwatcher : glad to have been of assistance. :) My star orbits spreadsheet isn't ideal for your purpose because it uses some parameters that are standard for binary stars but not for transiting exoplanets. Spherical trig isn't a major problem: like planar trig, there are only a few simple rules, ...
by granthutchison
28.09.2011, 23:08
Forum: Add-on development
Topic: CoRoT Exoplanets Catalogue
Replies: 31
Views: 11565

Re: CoRoT Exoplanets Catalogue

Selden sends me ... Before doing too much work of your own, you should download the current versions of extrasolar.stc and extrasolar.ssc which are maintained on the SVN tree at http://celestia.svn.sourceforge.net/viewvc/celestia/trunk/celestia/data/extrasolar.stc?view=log and http://celestia.svn.so...
by granthutchison
03.05.2011, 10:55
Forum: Development
Topic: Updating starnames.dat
Replies: 35
Views: 14919

Re: Updating starnames.dat

Regarding the Chinese names, most of them come from a very old book by Allen, who is known to have mixed up various things. Some of the names appear not to match Allen's assignments. I would promote removing the Chinese names, even if we could get an authority to confirm them. (Shouldn't we be usin...
by granthutchison
02.05.2011, 21:27
Forum: Development
Topic: New RECONS Top 100 list
Replies: 4
Views: 3759

Re: New RECONS Top 100 list

It's taken a while, but I've now commited a revised version of nearstars.stc, incorporating the latest RECONS list. I've also changed the spelling of Rigil Kentaurus in that file to match common usage, as is now reflected in the updated starnames.dat I've also commited.

Grant
by granthutchison
02.05.2011, 21:24
Forum: Development
Topic: Updating starnames.dat
Replies: 35
Views: 14919

Re: Updating starnames.dat

In the absence of any dissent (or indeed interest of any kind), I've commited the revisions to starnames.dat as I proposed above.

Grant
by granthutchison
22.04.2011, 00:35
Forum: Development
Topic: Updating starnames.dat
Replies: 35
Views: 14919

Re: Updating starnames.dat

Also: 51 Gem = BQ Gem not Bq; 23 Sex = RS Sex not Rs; 73 Dra = AF Dra not Af. I've been meaning to address these for some time. Bq Gem, Rs Sex and Af Dra are clearly errors in starnames.dat : text-processing somewhere along the line has broken the standard pair of capital letters which are the univ...
by granthutchison
08.03.2011, 22:36
Forum: Add-on development
Topic: Iss high resolution release 2
Replies: 38
Views: 17121

Re: Iss high resolution release 2

Is Celestia calculating the orbits for satellites differently than Stellarium does? Stellarium uses the same TLE's and it's projecting the position of satellites quite well in the right position. Selden sends me ... Yes, Celestia and Stellarium work differently. Celestia simply plots the orbital el...
by granthutchison
24.08.2010, 20:59
Forum: Physics and Astronomy
Topic: Up to 7 planets orbiting HD 10180
Replies: 4
Views: 3737

Re: Up to 7 planets orbiting HD 10180

I've added the system to extrasolar.ssc . It's available in the usual place on the SVN tree. http://celestia.svn.sourceforge.net/viewvc/celestia/trunk/celestia/data/extrasolar.ssc?view=log (I've also e-mailed Jean Schneider about the typo in the entry of planet f in the Extrasolar Planet Encyclopaed...
by granthutchison
23.04.2010, 21:51
Forum: Physics and Astronomy
Topic: A new nearby brown dwarf
Replies: 3
Views: 2701

A new nearby brown dwarf

Discovery of a very cool brown dwarf amongst the ten nearest stars to the Solar System.
I've added a very approximate definition to nearstars.stc. Celestia doesn't recognize spectral class T10, with a temperature of 400-500K.

Grant
by granthutchison
29.12.2009, 15:31
Forum: Physics and Astronomy
Topic: The Orcus-Vanth system
Replies: 10
Views: 4229

Re: The Orcus-Vanth system

400 km diameter corresponds roughly to the dimensions of Mimas which is the smallest currently known object that is gravitationally rounded. Seems like a fairly natural cutoff to me. As Gauss says, it seems rather unwieldy for the distribution Celestia . I'd personally be keen to keep outersys.ssc ...
by granthutchison
22.12.2009, 23:53
Forum: Physics and Astronomy
Topic: The Orcus-Vanth system
Replies: 10
Views: 4229

Re: The Orcus-Vanth system

I've now updated outersys.ssc with Orcus-Vanth and a rough rendering of Quaoar-Weywot. I haven't committed as yet, because I still need to shake down what sort of objects we want in outersys.ssc . Robert Johnston maintains a useful and regularly updated archive of TNOs here , which I've used for ref...
by granthutchison
12.11.2009, 19:20
Forum: Physics and Astronomy
Topic: Yet another new ring detected around Saturn
Replies: 23
Views: 6929

Re: Yet another new ring detected around Saturn

2. The Moon S/2008 S1 (now named Aegaeon) and the associated G ring is not included in Celestia. Just bumping this thread to note that an orbit for Aegaeon was published on 1 November, so it now appears in numberedmoons.ssc , as of SVN revision 4909. If you use my add-on poormoons.ssc (recently dis...
by granthutchison
30.09.2009, 16:51
Forum: Bugs
Topic: Amalthea
Replies: 3
Views: 2005

Re: Amalthea

Bob: I'm using the Amalthea distribution model and jupitermoons_locs.ssc , as stored on the current SVN tree, and have no problems. For your reference, here is a screenshot of what my Amalthea locations look like. There's also a large crater called Gaea at Amalthea's south pole. And here are the cor...
by granthutchison
27.09.2009, 18:47
Forum: Add-on development
Topic: Organization of .ssc files
Replies: 6
Views: 3090

Re: Organization of .ssc files

The file extrasolar.ssc is already maintained as you describe, using a table in which the published parameters are compiled, combined with some code which exports the ssc file in a form Celestia understands. The entries for planetary moons are largely generated directly from JPL's Horizons ephemeris...
by granthutchison
24.09.2009, 22:28
Forum: Bugs
Topic: 2004 XR190 wrong radius given
Replies: 4
Views: 2264

Re: 2004 XR190 wrong radius given

Yes, my error with the radius. Thanks for the correction, mopc . :) I've committed a correction to SVN, and have replaced the dead InfoURL with a link to the discovery paper cited by Fridger. Outersys.ssc is overdue for a more general review to update its content, but it'll need to wait a bit while ...
by granthutchison
17.06.2009, 16:53
Forum: Development
Topic: Binary Orbits Revisited!
Replies: 106
Views: 29779

Re: Binary Orbits Revisited!

t00fri wrote:OK Grant, I shut up if you prefer.
Not at all. Feel free to carry on without me. :)

Grant
by granthutchison
17.06.2009, 15:45
Forum: Development
Topic: Binary Orbits Revisited!
Replies: 106
Views: 29779

Re: Binary Orbits Revisited!

All this "seriousness" is impossible with your specific claim that e.g. GX And was less popular than Groombridge 34 since barely any "Celestian" whom one might ask has ever heard about GX And or Groombridge 34 ;-) . You missed out the bit where I defined my relevant sub-populati...

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