From my +33° latitude, today’s OOTW, NGC 1851, is not a particularly flashy object, but it is a fascinating and fairly unique globular cluster nonetheless. It is located at declination -40°, low in the western corner of the small and faint constellation Columba, the Dove, which is mostly directly south of Lepus, the Hare, which is itself mostly directly south of Orion, the Hunter. It never gets too high above the horizon for me, about 15° or so, and it is probably even lower for many readers here. Still, it is a nice surprise for everyone who looks at it for the first time. I vividly remember the first time I star-hopped to NGC 1851 about 35 years ago with my brand-new C-8, I was surprised just how pretty it was and how its core was unexpectedly bright. It is one of the most compact GC’s known. I’ll bet it is a wonderful sight from Down Under. Here is a nice photo by Damian Peach from Siding Spring, Australia…
But wait! There is more to the story than NGC 1851 being just another bright Globular Cluster. It seems that NGC 1851 is a possible remnant of a dwarf galaxy! This would put it in rare company, for only about 8 or 10 other objects can say the same thing. Studies show that there are at least (2) subpopulations of stars formed at different times, with each showing different metallicity measurements, making this an ‘anomalous’ cluster. So, there are apparently (2) scenarios to consider… one is that NGC 1851 is one of several globular clusters left over from a dwarf galaxy that was previously ripped to shreds by the Milky Way, ,or that NGC 1851 is the ‘kernel’, or core, of a former dwarf galaxy… but in either case it appears to be of extragalactic origin. I need to say that I have learned much of this from the recent availability of Volume 6 of The Annals of the Deep Sky (Jeff Kanipe & Dennis Webb), and there is still even more to the story, so check it out for yourselves.
In any case, this is a terrific object, especially if you can get yourself way down south for a really good view.
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