The Caldwell Objects

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5.25 and 5.95, lies 2° south of the globular; it ous. James Dunlop listed it as the 337th object in
shines with a distinctive orange hue.
his 1827 catalog, describing it as a “very bright
NGC 1261 does not pack a visual punch at low round nebula, about 1½' diameter, pretty well
power in the 4-inch. This is not surprising given defined and gradually bright to the centre.”
the object's great distance. NGC 1261 is a halo At 72x the globular offers the 4-inch a hint of
object 55,500 light-years from our Sun and 59,400 resolution. With averted vision its nearly 3'-wide
light-years from the galactic center. Although the central condensation appears as a swollen mass
cluster is far from the plane of the Milky Way, the punctuated by several stellar clumps. The outer
field at 23 x is busy with stars congregating so envelope looks fractured, especially to the north.
closely together that they look like dim deep-sky A high t power the cluster's core starts to resolve
objects or minicomets, giving rise to many false well, with many similarly bright stars in
alarms that something new and wonderful lurks geometrical patterns separated by apparent dark
near the cluster. I wonder if any of these lanes or absences of stars. In this way NGC 1261
asterisms fooled John Herschel, since during his appears very similar to NGC 5286 (Caldwell 84),
second observation of the cluster he penned: " A and indeed, each cluster has a horizontal-branch
very faint nebula (??) precedes [lies to the west]." magnitude of 16.7 and a smattering of 13th-
The cluster's small form all but hides among magnitude stars. But NGC 1261 "looks" older, as
these fuzzy apparitions. At low power you'll find if it's decaying. In fact, high-resolution hydrogen-
NGC 1261 marking the eastern arm of a 40'-long alpha images of the cluster's core taken with the
"warped Northern Cross" asterism of 8th- and European Southern Observatory's 3.5-meter New
9th-magnitude suns. It manifests itself as a soft Technology Telescope show a similar effect: the
but compact 8th-magnitude glow immediately core appears to be melting, with globs of starlight
southwest of a roughly magnitude-9.5 star. Once dripping southward from its northern rim. The
you fix your gaze on it, the cluster is obvi-
cluster is about 15 billion years old, according to
some es-
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Deep-Sky Companions: The Caldwell Objects