The Caldwell Objects

104 & 106
cluster's members, especially if the skies were
darker. Still, what a glorious sight to see a core so
tight, to realize that the bonds at this cluster's
heart had defied the gravitational tug of our
galaxy. I looked upon this timeworn celestial
warrior and felt honored to have made its
acquaintance.
Barbara Wilson observed NGC 362 on
November 4, 1994, while observing at an altitude
of 9,700 feet (2,900 meters) from Tacna, Peru. Her
view of it, through a 7-inch f/5.1 telescope, was
equally impressive: "Much smaller than 47
Tucanae with a bright core, very bright, stars are
fainter. . . . Cluster is fuzzy; with a 20-mm Nagler
[eyepiece] it is about 3' in size but the core is very
bright, not resolved in the 7-inch. Core is near
stellar, but I can see about 20 or 30 stars near the
core." Ernst Hartung found that he could
definitely resolve the cluster with a 12-inch
telescope: "This beautiful globular cluster is well
resolved to a very bright compressed centre, the
main part 2' wide and the scattered outliers
reaching to 4'." He also claims that NGC 362 can
be resolved with a 6-inch and that it "looks granular"
in a 3-inch.
Hartung observed NGC 362 from much
darker skies than I had in Wellington. So maybe
that's the key. But why, then, didn't Wilson
resolve the cluster in her 7-inch under the clear,
dark skies of the Peruvian Andes? Wilson's
response to this question raises an interesting
point, one that I haven't seen addressed
elsewhere: that resolving a globular cluster is
highly subjective. "Regarding [the] resolution of
NGC 362," Wilson writes, "I guess it depends on
one's definition of resolution. I don't know what
Hartung used for his criteria. Does one mean
clarity, crispness, focus [,] smoothness of image,
visibility, distinctness as all synonyms for
resolution? My definition of resolution of a
globular cluster is when one is
412
resolved to the core. When I can see stars all
across the face of the core of the cluster, I call it
totally resolved. The outer parts are a given,
meaning these stars usually are resolved in a
bright cluster. If I can see most of the cluster's
stars from its outer periphery to its mysterious
center, it is 80 to 90 percent resolved. I called
NGC 1261 in Horologium [(Caldwell 87)] semiresolved
because its bright little non-stellar
nucleus did not show stars, and had fuzzy edges.
I saw only a few stars clearly. I remember NGC
1851 in Columba from the Winter Star Party
appearing mottled in the center using 500x,
otherwise it resolved in its outer portions. But I
would not call it resolved, but nearly so."
CCD images of NGC 362 have revealed dark
patches distributed asymmetrically around the
cluster's center. Argentine astronomer Mariano
Mendez and his colleagues estimate that the
cluster contains about 0.1 solar mass of dust.
Patches of dust have been imaged in other globulars,
but have they ever been detected visually?
Walter Scott Houston thought they were worth
pursuing because "it seems reasonable that some
dust clouds could be visible to the eye." So give it
a try.
Before we move on to 47 Tucanae, I have a
challenge for you. Moving 1° north and slight-
Deep-Sky Companions: The Caldwell Objects