Here is a new stars database for Celestia

[Rigel]

I am glad to announce to Celestia users, that they can download a new stars database for Celestia with a total of 788514 stars.

Here is the link :

http://perso.wanadoo.fr/celestia.stars/

You will also find on this site more information on the methods that were employed to extract stars from the Tycho stars catalog and how they have been added to the database of Celestia.

I hope you will enjoy your new Celestia sky...

[jrobert]

Wonderful work!! Thanks, Rigel

[Rassilon]

Well chris should be adding this with the next version of celestia as a standard...superb job Rigel...I will now include this with any system I create using any of these stars

And this hardly slows my system down at all...even on full count

[Astrojockel]

Hey, absolutly top work

That?s great, i love it and it will be my standart database for now.
Waiting 15 years for GAIA to be completed will be much easier.

But what?s star HD 42272 ? Nice to see, that Sol now has a companion
We should call him "Rigel" and rename beta ori to something other

Chris, when will be the "shell at 8154,17 ly"-problem fixed ? Have you any idea, what it could be? After that celestia will nearly perfect.

And last but not least what?s about the distance of the trapezium in Orion ? With the new database it looks like real, but the distance is much to high. It should roughly 1500 lys.

p.s. On my system, a PIV 1,7GHz with a G2MX400 and 512MB, it run smooth with max stars visible. I think, there?s enough room for even more stars.

[Rigel]

Astrojockel,

didn't you know our Sun had a companion star - HD 42272 - at 206 au distance of it ? :wink:

More seriously, it is a bug, not really in the extraction procedure, but in the Tycho catalog, because HD 42272 (TYC 1881-1526-1) has a B-V color index of 3.232 in the catalog. This value seems completely false to me.

There could be another problem with HD 169197.

When I have some time, I will remove HD 42272 from the database, and look for other stars with strange values. It will be soon a stars database V1.1.

Don't forget that the extraction procedure leads to approximative distances. See the detail of this method on my web site.

[Astrojockel]

There could be another problem with HD 169197.

When I have some time, I will remove HD 42272 from the database, and look for other stars with strange values. It will be soon a stars database V1.1.

Yeah, i think, there are some other. If i look in the starbrowser, more than 500 stars are within 11 ly around the sun. Most are red M-dwarfs. I think, that?s much to much. Correct me if i?m wrong.

Ahh, v1.1 sounds good I?m waiting for

[The Clickman]

Looks good, but if we looking the entire database, look like a sphere with a disc on the plan of the galaxy ! :-)


this is normal ?

good work !

[Astrojockel]

this is normal ?

No, not realy. That?s the "shell at 8154,17 ly"-problem.
It?s not a bug, it?s a feature

[chris]

The shell at 8154 ly results from Celestia limiting the distance of stars . . . There are a number of bad measurements in the HIPPARCOS catalog that place certain stars unrealistically far from the Sun--outside of the Milky Way in many cases. Rather than throw them out, Celestia fixes their distance at an arbitrary limit. I'm sure that I can come up with a better way of handling bad stars so that the weird shell disappears.

--Chris

[billybob884]

this is normal ?

No, not realy. That?s the "shell at 8154,17 ly"-problem.
It?s not a bug, it?s a feature

It semas to me it should be a bug instead of a feature

[selden]

BillyBob,

Since your comment seems to be meant seriously, I just thought I should clarify things a little:

"It's not a bug, it's a feature!" is a sarcastic remark that's common in the computer software industry. It's used when everyone knows it's a problem and it's going to be fixed Real Soon Now. (RSN is another equivalent remark -- meaning that the programmer has the best intentions of fixing it, but it's really low on the list of priorities and might happen sometime in the vague, far distant future. If you're lucky.)

[Rigel]

There are 4196 stars with negativ parallax values in the Hipparcos catalog. Thus their distances cannot be computed.

But the spectral type and the luminosity class are generally given.

So we could apply the same procedure as I applied to extract the Tycho stars, to get a good estimation of the distances of these stars, from fitting functions, B-V color indexes and visual magnitudes.

[billybob884]

BillyBob,

Since your comment seems to be meant seriously, I just thought I should clarify things a little:

"It's not a bug, it's a feature!" is a sarcastic remark that's common in the computer software industry. It's used when everyone knows it's a problem and it's going to be fixed Real Soon Now. (RSN is another equivalent remark -- meaning that the programmer has the best intentions of fixing it, but it's really low on the list of priorities and might happen sometime in the vague, far distant future. If you're lucky.)

sorry, didn't mean to be offensive.


Mike M.

[Redfish]

Yeah i love the database as well.

Too bad there is quite some slowing down when you look at the center of the galaxy, where most stars seem to be located.(When you have max visibility of all stars turned on)

And the star distance limit. Oh well, it looks artificial, but i can also live with it.


But hey 800k is better than 100k!

[selden]

Mike,

I certainly didn't take your comment as being offensive. It just seemed to me that perhaps you were unfamiliar with that particular term. It can be hard to tell when someone is being funny. Sometimes I get carried away with explanations, too.

Now I think I'll go back and stargaze some more :)

[Rassilon]

sarcasm is not practical most times in a forum....suppose thats why I get flamed alot

[Guest]

I downloaded the 2.0A versions of the stars expansion and I've found it places numerous Giant (Class III) stars very near to the sun, closer than Barnard's Star in some cases, why is this happening? Why are these stars being placed so close to the sun?

[granthutchison]

I downloaded the 2.0A versions of the stars expansion and I've found it places numerous Giant (Class III) stars very near to the sun, closer than Barnard's Star in some cases, why is this happening? Why are these stars being placed so close to the sun?

Seems to be a problem with the Tycho database, from which Rigel's expanded catalogue is derived. See this thread
http://www.shatters.net/forum/viewtopic.php?t=1836 for a little more discussion (but not much). For me, it makes the expanded database pretty much unuseable , though it does look nice when viewed solely from within the solar system.

Grant

[MrBatman]

Is Wolf 359 in it?

[granthutchison]

Is Wolf 359 in it?

Doesn't appear to be. You can query the database yourself at http://cdsweb.u-strasbg.fr/viz-bin/VizieR?-source=I/239.

Grant