Position of stars on the screen

General discussion about Celestia that doesn't fit into other forums.
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Remco65
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With us: 18 years 10 months

Position of stars on the screen

Post #1by Remco65 » 16.03.2006, 22:26

Hello,i have a question ,are the positions of the stars shown on celestia(also the faint stars down to magnitude 10 or fainter) the real positions as plotted in staratlases? And if so ,it is very difficult work for the people who have made celestia. Can you answer my question? thank you.

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selden
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Post #2by selden » 16.03.2006, 22:37

I'm not sure what you're asking.

Celestia uses the Hipparcos catalog, translated into Celestia's own format. Writing a program to do that translation is relatively easy.

The Hipparcos catalog is available at http://cdsweb.u-strasbg.fr/cgi-bin/Cat?I/239
The positions of stars in that catalog are accurate to tiny fractions of an arc second. The positions plotted in most star atlases are not as good as that, since they're ink on paper. The positions in the Hipparcos catalog are better than the widths of the dots of ink.
Selden

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Remco65
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Post #3by Remco65 » 17.03.2006, 15:22

Can i also find(if i know where it is) the star Cygnus x 1?

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Remco65
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Post #4by Remco65 » 17.03.2006, 15:24

And how can i travel to it? (in celestia of course)

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selden
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Post #5by selden » 17.03.2006, 15:46

Cygnus X1 is too far away for Hipparcos to measure its distance, so it is not included with Celestia.

[edit]
Correction: the star that Cyg X1 orbits around, HD 226868 = HIP 98298, is in Celestia, although the black hole itself is not. Sorry for the confusion.
[/edit]

However, there is an Addon by "Cham" which will cause Celestia to display this object.
http://www.celestiamotherlode.net/creat ... gnusX1.zip

It's rather large (18.7MB) so be patient while downloading it.

You would travel to it just as you would travel to any other object in Celestia. If you haven't already, you should read the Celestia Users Guide by Frank Gregorio. It's available in several translations on the Motherlode
http://www.celestiamotherlode.net/catal ... ation.html
Selden

Topic author
Remco65
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With us: 18 years 10 months

Post #6by Remco65 » 17.03.2006, 21:37

Thank you very much! And the planets discovered around other stars are also shown in celestia ,are the positions around the star the real positions? And can you also travel to that planet too? Thanks.

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selden
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Post #7by selden » 17.03.2006, 21:42

Short answer to your latest questions: yes: accurate and can be travelled to.

Longer: Because of the way they're detected, astronomers can't measure the orientation or inclination of most exo-planets' orbits, so Celestia can't show those values accurately.

Read \data\extrasolar.ssc for the details. It's a plain text file, so you can open it with Notepad (assuming your computer is running Windows).
Selden


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