Yes, the deeper catalogs have holes around bright objects (keeping in mind that "bright" is a relative term). They were all auto-scanned from the original Palomar Observatory Sky Survey plates, where "bright" objects are overexposed, and glare extends a large distance around bright stars. Even things like the ring nebula are nearly white on the plate, so there are few stars in the deep catalogs within that region.
But that doesn't exlain what's happening in Dieter's first picture. In v2.76, the GSG catalogs can only be used in fields up to 2 degrees. I suspect something similar is causing a problem here. -John --- Len Philpot <[EMAIL PROTECTED]> wrote: > > What the problem? (HSC-compact, my grphiccard?) > > > > any help available > > It's not your video card, but rather the catalog. The same effect is > visible in MegaStar. I seem to recall reading long ago somewhere about > what caused such "holes", but I can't recall for sure. I think maybe it > had to do with the increasing difficulty in autodetecting faint stars in > close proximity to the glare of bright objects when the catalog was > created. > > You can see a related effect if you zoom in closely to some globular > clusters (eg., M13). There is an increase in starfield density, then a > sudden black hole where the stars got too dense to catalog individually. > > -- > Len Philpot ><> > [EMAIL PROTECTED] http://philpot.org/ > > > > > > > Yahoo! Groups Links > > > > > > > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/skychart-discussion/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
