Celestia Forums

There seems to be a distinct ring of stars at 8154.176 ly's from Sol. I recently posted a bug report about the 16308.35 limitation and now believe that is a limitation of the Hipparcos catalog but what is this at 8154.176 ly's from Sol?!

Here, take a look:


I have the camera set to about 47000 ly's from Sol and galaxy rendering is off.

PS: Pentium 4 1.6GHz, 512MB, Geforce2 GTS 32MB DDR

Honestly, I dont see anything.


Mike M.

You should be able to see it better in the following AVI file:

http://www.geocities.com/rojomoyo/distinct_ring.avi

This is probably a consequence of the accuracy of the parallax for the stars. The distance measurements of these stars are so small, that they all come out at 0.40 milli-arc-seconds which corresponds to 8154.176 lightyears, even though in reality their parallaxes differ by an amount that the Hipparcos satellite wasn't able to detect.

You want the problem solved, then help send a more accurate satellite up there...

Link not working...


Mike M.

I'm not sure the limited precision of the Hipparchos data would fully explain this. The binning of parallax values should produce a series of spherical shells of stars at related distances. But why would one particular shell at one particular distance be so prominent? It seems to me more likely that, if not a bug, this must be due to some kind of selection effect in the Hipparchos data, possibly related to the magnitude limit and luminosity distribution of the stellar population. It does seem very strange.

- Hank

As an afterthought, I put the pictures and AVI on my site at Geocities, but due to the amount of traffic recieved by my posting links here to my site, they say my bandwidth consumption has been exceeded. That is most likely the reason you're getting link failures. Please tell me your suggestions where I can post content and not get penalized for bandwidth consumption. Thanks

your best bet in posting pictures is find a site that allows remote linking...most now you have to pay for...like mine I pay $10 american a month...

Right click the link and select "save file as"
works fine

Looks like a strange flat disk of stars