Hi folks,

About use of guide8.zip with a Guide 7 disk: yes, as far as I
know, this will work. I made no explicit attempt to maintain
backward compatibility, and it's entirely possible that I did
something that "breaks" where you least expect it. (The only
thing I can think of is that FILELIST.DAT from guide8.zip should
not be used with a Guide 7 disk. The version from guide8.zip
describes the files as laid out on the Guide 8 disks, some of
which are not placed as they were in Guide 7. You may find
other "breakages"... this is not an area I've tested extensively;
my main area of interest has been seeing to it that Guide 8
software works with Guide 8 disks.)

However, doing this doesn't get you any real advantages. The
problem is that, to get most of the new features of Guide 8,
you need data files that are only present on Guide 8 disks.

About NGC 2299: both the SAC 7.2 data and the NGC-IC
Project data identify this as being also known as NGC 2302.
Larry, I dunno where the "nonexistent" definition comes from,
but perhaps it just means "this object ought to be known as
NGC 2302; the 2299 ID is a duplicate." As Joe mentions,
if you zoom in on it, it becomes very apparent that yes, there
is a real cluster of stars there.

(Incidentally, this can be an interesting test of the data.
There are about 30,000 of those "little pictures" of DSOs,
meaning that some relatively obscure objects are covered.
You can frequently see cases where the catalogued position
does not match that of the DSO as shown in the image, or
cases where the position angle is "backward" from what
it ought to be.)

Joe, about SA2.0: the folks who put that together chose
stars mostly around mag 14 to 16, apparently thinking that
these had the greatest astrometric quality. (Brighter stars
might saturate on a CCD, and fainter stars might not give
a good enough signal... keep in mind that USNO's _only_
interest in SAx.0 was to provide a catalog for astrometry,
not for star charts. It's a bit like having a map in which all
the main roads and cities, and a random 90% of the smaller
roads and cities, have been omitted.)

-- Bill