On Apr 18, 2005, at 3:37 PM, Alsing, Paul wrote:
> NGC 6520 is a nice cluster, but it is made even more appealing because
> it is
> next to one of the darkest of the dark nebulae, B86, the Inkspot.
>
> Very nearby this pair is a nearly unknown globular cluster, only
> discovered in
> (I think) 1989, from plates. It has the designation Djorgovski 2
> (E456-SC38). It
> is easy to find by drawing a line from the center of the cluster
> through the
> center of the dark nebula and extending that line about twice it's own
> length,
> arriving at a small "keystone" of stars that look a lot like the
> Hercules
> keystone, with one corner being a wide double star. Smack in the
> middle of that
> keystone is Djorg 2. It is not too hard to see, even in a modest
> instrument.
> This globular is reddened by interstellar matter a whopping 8 or 10
> magnitudes,
> meaning that it would rival the brightest of the bright globulars were
> it not
> for the intervening dust!
To add to this field is another little-known globular – NGC 6540, which
is 37' E of NGC 6520. In fact, Djorgovski actually thought he
discovered this object about 10 years back, so it is also listed as
Djorg 3, although it first found over 200 years ago by William
Herschel. Doesn't look very globular-like, though, but because of
Djorgovski we now recognize it as a globular (and not an open cluster).
17.5" (7/10/99): this interesting globular is located nearly midway
along a short 1.5' E-W arc of a half dozen or so mag 13-14 stars that
are bowed out to the north. The globular is a faint, round, 40" glow
which is embedded just inside the center of this string which extends
beyond the globular to the west and east. At 100x, this string, along
with the haze of the cluster creates the impression the globular is
quite elongated.
Steve
Received on Mon Apr 18 19:48:45 2005