Galactic Redshift Survey Question

[FCVPI99]

so i added the Galactic Redshift Survey to Celestia and im wondering why it displaying waves or rings almost like info is missing am i the only one who is having this problem?

[selden]

Exactly which galactic redshift survey Addon do you mean? There are several.

It also would help if you were to include a picture, with circles and arrows indicating the regions that you're asking about.

The deepest galactic surveys have been made only of specific regions on the sky. When you look at them in 3D they look like fans, with the center at the Earth. They show "voids" and "filaments" which are real structures in the way galaxies are distributed in space. See http://en.wikipedia.org/wiki/Galaxy_filament

[FCVPI99]

from what i see on celestia motherlaod there is only 1 Galactic Redshift Survey
the other you might be talking about are Quasars Add-On, Quasars and AGN, and SDSS DR2 Galaxies

but here is the link
http://www.celestiamotherlode.net/catal ... don_id=566

i used the 300K version

as for photo i took a screen shot of what im taking about but there is not a jpg upload button so it looks like i cant post a photo
i did however upload the photo to the link above

[selden]

The link for including images in a post is just below the editing ares, in the section which starts with

Upload attachment
If you wish to attach one or more files enter the details below.

That section is just above the area which shows the other posts in the thread.

[FCVPI99]

ok here is the photo

[selden]

The readme file includes the following:

Unlike the 100k release which contained z values with a resolution of 0.000001, the 2dF final release catalog specifies redshifts with a z resolution of 0.0001.
This causes problems for the objects with small redshifts

Sorry I wasn't explicit about what the problems are. Specifically, the limited z (redshift) resolution causes distances to be quantized in rather large steps. As a result, all of the objects are drawn in spherical shells. That becomes particularly obvious when you magnify the view to look at the objects which are relatively close to us.

[FCVPI99]

ok so the 100K version is better? or the same?

cuz to be honest you were just specking greek

[selden]

Both datasets are "right".

The extra digits in the smaller dataset are misleading.
The distances simply weren't measured that accurately.

In the larger dataset, the distances to individual galaxies might actually place them anywhere between the closest 3 or 4 "rings" that Celestia shows. Celestia doesn't have an easy way to show how badly the distances were measured.