rings?

General physics and astronomy discussions not directly related to Celestia
Guest

rings?

Post #1by Guest » 19.03.2004, 00:10

using the 2 million star database it seems that the stars are organized in some sort of rings around sol, what is the reason of that?
You can clearly view them from a distance of 30000 ly above Sol, looking down on the galactic plane.

Guest

Post #2by Guest » 19.03.2004, 00:30

Damm, those religious guy's back in gallileo's day were almost right, it's our sun thats at the center of the universe!

Seriously, we observe from earth and how far in any given direction we see is greatly dependant on what is in the way. Also our estimates of distances are not exactly accurate past a certain point. Then there could be rounding errors in the calculations celestia uses etc etc. The net result is what you observe, just don't treat it as gospel and all should be ok.

Guest

Post #3by Guest » 19.03.2004, 13:16

That's what I had in mind, rounding stuff or maybe "regions" of distance measuring.
And in the same star database, when looking from sol into the milky way there are areas which contain less stars - that's because dust is obscuring it, right?

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Post #4by selden » 19.03.2004, 16:32

A plot of the number of stars observed per square degree in galactic coordinates by the Hipparcos satellite and used in the Tycho catalog is at http://astro.estec.esa.nl/Hipparcos/CATALOGUE_VOL1/MISSING_FIGS_3.3/f3_3_001.pdf

Some regions (mostly in the plane of the galaxy) have reduced numbers of stars because of obscuring clouds. The over-all number of stars is reduced in the regions north and south of the galactic plane because the density of stars away from the plane is relatively low.
Selden


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