Greg Crinklaw wrote:
Larry G. wrote:
I had the FOV zoomed out to see an entire hemisphere at a time.
I could rotate the FOV and the clumpy/disc-band pattern
remained consistent.

Perhaps the Virgo cluster is aligned along a more-or-less
linear boundary between two or three different void-bubbles
in the cosmic foam.

Sorry Larry, but you can't see the "cosmic foam" in looking at only the
brighter galaxies. The bright galaxies are the ones nearby, and it just
isn't a sufficient sample. Even with my SkyTools, which can plot over a
million galaxies on a single chart, such structure is only at best
hinted at. The other problem is that once you have enough galaxies in
your sample the close ones overlap the far ones, and unless you have a
means of separating them by distance you aren't really going to see the
structure. That is why this structure was only first revealed by deep
redshift surveys.


Among NGC galaxies, you may well be seeing the elongation/flattening
of the Local Supercluster, roughly centered on the Virgo cluster.
Gerard de Vaucouleurs was almost alone for years in claiming
this as evidence for structure on a scale larger than obvious
clusters. He even defined a coordinate system aligned with this
"supergalactic plane" (which runs almost perpendicular to the
Milky Way plane), in which you can find positions
transformed at, for instance, ned.icpa.caltech.edu. The visibility
of this clump in galaxy catalogs owes a lot to the relatively
lwoer-density areas around it in most directions, which reduces
the foreground-background clutter than Greg mentioned.

Bill Keel

Bill Keel