The Caldwell Objects

each square arcminute of its disk shines with the
light of a magnitude-13.2 star. Some patience is
required to find NGC 7006 because the cluster
resides in a region devoid of bright naked-eye
landmarks. The closest such landmark is
magnitude-4.5 Gamma (γ) Delphini, the nose of
the celestial Dolphin, 3.5° due west
of the cluster. Owners of equatorially mounted
telescopes will have no problem finding the
cluster, since they just have to sweep their
telescopes eastward with a low-power eyepiece.
(In a more relaxed vein, Walter Scott Houston
suggested setting the telescope on Gamma
Delphini and waiting 15 minutes for the globular
to drift into view.) Those using altazimuth
mounts should refer to the finder chart here.
Note that NGC 7006 is part of an upside-down
and tilted Τ of 6th- to 7th-magni-tude stars. First
use binoculars to locate this asterism; then, using
the widest field your tele-
The Caldwell Objects
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scope provides, sweep from Gamma Delphini to
the T. If you have a Telrad finder, place the right
edge of the widest illuminated ring on Gamma
Delphini; the left edge of the outer ring will slice
through the T. Don't expect to see the cluster in
binoculars. I tried, with hand-held 7x50s and
10x50s, but failed. Houston tried with 16x40s
mounted on a tripod, and, though he knew
exactly where to look, he could not see the
cluster through them.
Although NGC 7006 has been seen in telescopes
as small as a 3-inch, doing so is a challenge.
At 23x in the 4-inch Genesis under dark
skies, the cluster appeared as a faint glow whose
body had only a little more substance than that of
NGC 2419. To pull NGC 7006's glow out from the
background, Scotty suggested using more than
50x; with his 4-inch refractor 100x seemed best to
him. In the Genesis at 72x the cluster shows a
definite roundness, with hints of a core and a
breathlike extension or outer halo. In time the
core becomes obvious, as does the outer
envelope, which causes the cluster to swell
slightly with averted vision, just like a "blinking
planetary." At 130x there is no hint of resolution.
The cluster keeps its form but takes on a pasty
glow The core begins to show stubby crosslike
arms or appendages. NGC 7006's amorphous
nature should not surprise us. After all, the
globular is one of the most difficult to resolve,
and its brightest star shines at a feeble magnitude
15.6. Christian Luginbuhl and Brian Skiff were
unable to resolve the cluster with a 10-inch
telescope even in good seeing, though they did
resolve a few faint stars over a granular
background with a 12-inch at 475x. Using a 13.1inch
f/4.5 reflector, Barbara Wilson found the
cluster to be a very dense fuzzball with no
perceptible individual stars. Photographs taken
through large telescopes reveal the cluster to be a
tight snowball of starlight with an almost
hexagonal core. A promi-
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