The Caldwell Objects

82
tail of stars that stretches nearly 1½° to the northnortheast
of HD 150136, where it connects with
another cluster, NGC 6200. Interestingly, NGC
6193's discoverer, James Dunlop, also noted this
feature: "A very considerable branch or tail
proceeds from the north side, which joins a very
large cluster." Another swath of Milky Way
curves away to the north-northwest from the
bright wedge's western edge. My mind pieced
everything together to see an enormous "comet"
with a parabolic hood smashing into NGC 6193.
The Milky Way looks very peculiar in this
region, especially since its boundaries seem to
conform so sharply to specific stellar patterns.
330
One night, as I pondered the view, I noticed a
dark pool of nebulosity southwest of the bright
wedge; its edges were filigreed with sparkling
suns. This pool of cool, opaque matter turns out
to be a bright source of infrared radiation and
thus a likely site of star formation — and it is
readily visible in a 4-inch telescope. It's very
difficult (at least visually) to discern any emission
or reflection nebulosity in NGC 6193 with a small
telescope. Certainly the glow from the bright
wedge at the cluster's core is obvious in the 4inch.
But how much of that glow comes from
faint, unresolved stars rather than from heated
gas or reflective dust? I do not know. Dunlop did
not suspect the presence of any
Deep-Sky Companions: The Caldwell Objects