In a message dated 9/29/03, David Kingsley writes:
>Hi Steve,
>I am always amazed by the quality and detail of your observing notes. I
>could trace out all the major features of 6946 based on your description.
>However, I am not sure we are talking about the same object when it comes to
>the HII region and the superstar cluster. Your "very small HII not" sounds
>like it was located near the end of the long curving arm that projects form
>the North side of the galaxy core and trails to the east. In contrast, the
>massive star cluster/bubble region is found in a much shorter fainter arm
>that projects form the south side of the galaxy and projects to the west.
>This arm is not one of the main 3 brightest arms of the galaxy, and is
>actually located south of the third arm in your description (the one that
>shoots sharply to the North from the core).
You may be right that I missed the bubble region + globular, which just means
that I have another interesting object to add to my observing list!
As far as other super-star clusters that are visible in external galaxies, a
great target is NGC 1569 which has two or three superimposed near the core!
Here are my notes from the past two years:
17.5" (1/12/02): very bright, elongated 5:2 WNW-ESE, 2.5'x1.1', high but
irregular surface brightness with an asymmetric appearance. The very bright
core is mottled and irregular and is offset to the NW side of the galaxy! At
380x, there are two stellar "nuclei" within this glow. The brighter stellar
nucleus is fairly easy and a fainter stellar point is close SE. There is also
a strong impression of a third stellar spot close W of the central nucleus.
These faint "stars" are actually luminous super-star clusters, the most
massive known type of star clusters (color image at
http://www.lowell.edu/users/dah/n1569p1_color.gif). A mag 10 star is close
off the N side, 1' from center and a mag 13 star is just off the SE end.
N1569 is probably a member of the Maffei 1 - IC 342 group.
17.5" (3/1/03): at 380x this is a bright, very elongated galaxy with an
unusual asymmetric appearance, situated less than 1' S of a mag 9.5 star!
Extended nearly 5:2 NW-SE, 2.0'x0.8'. The bright core is offset to the NW
side of the glow, with a tail extending SE, possibly bending at a slight
angle to the core. Two stellar "nuclei" are visible in good seeing. The
brighter "star" is embedded with the core, possibly just slightly N of
center. A second fainter "star" is close SE, near the edge of the core and is
visible intermittently. These stars are actually SSC's (luminous super-star
clusters).
Steve
