ngc 2158 behind M35

At CalStar, Dan Wright and Craig Colvin were having fun gazing at 2158 -

>Next, Craig put lots of power on NGC 2158: that ancient, distant,
>probably very mighty cluster lurking off the side of M35. It was my
>finest view ever of that object. My thanks to Craig, and to the
>other fellow who suggested the object ...

I've spent a lot of time sitting and staring at that cluster. It's
dense and luminous enough to let on that it's big and far away.
Burnham has an evocative and thorough description of it. It's been
measured to be 4900 parsecs from here, about 16 kly, more than 6
times the distance of M35. "This places it far out near the outer rim
of the Galaxy." And yes it's old, with an H-R diagram similar to
those of 7789 in Cassiopeia and 752 in Andromeda, older than the
normal open clusters while still younger than the ancient ones like
188 in Cepheus. They're part of a short list of intermediate-age
clusters. 2158 is probably about 800 million years old.

It's certainly mighty - Burnham says "this cluster would nevertheless
rank among the finest of all galactic clusters if it was as near to
us as M35 itself."

But it's Burnham's reach of vision, to describe 2158 as out near The
Rim, that captivates my imagination.

Thanks for the vicarious eyepiece thrill, Dan.

DDK

-- 
Jamie Dillon <mavericks@redshift.com> <*>
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"If there's a hull breach I'm screwed."
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