open cluster NGC 2017 may not really be an open cluster at
all. Nonetheless this tight grouping of stars is a
pleasing sight. The five brightest stars are
quite colorful and can be viewed in any instrument.
Ron Bhanukitsiri describes the grouping in his TV-102 as,
"A group of 4 stars at 30x with yellow, blue and dark
orange color, quite lovely. A 5th star popped into
view at 110x."
inspection two of these stars split into close pairs.
AB is the close double BU 321, a 6.4+7.9 mag pair separated
by 0.61" at PA 156o.
CD is the close double HJ 3780, a 8.5+9.2 mag pair separated
by 1.4" at PA 356o.
The AB pair is usually described as blue. I had
difficulty describing the color of the CD pair, finally
settling on purple-green. Star F is invariably
described as deep orange or red.
In my 18-inch
F/4.5 my best view of the grouping as a whole came at
270x. I noted a slight fuzz surrounding the
group. This fuzz did not respond to the OIII filter
and I concluded that it consisted of scattered light from
the bright stars. Interestingly, a similar oval
haze can be seen in DSS images if processed extremely.
I wonder, is this scattered light too, or is there some