Gem at the bottom of the falls

March 10, 2008 - pm - T4S3 - 29 degrees
Kemble's Casecade is beautiful in itself, but at its bottom this stream of stars pour into a small, open cluster that is dominated by an absolute gem of a pair of perfectly matched, magintude 7 stars.

I "discovered" them again last night when I turned the 100ED towards the cascade - but I remember "discovering" these about six years ago when I was using Myauchi 32X77 binoculars in the observatory. These had been my instrument of choice for reintroducing myself to the night sky after several years of being totally wrapped up in the Web development and teaching online.

One of the interesting things about Kemble's Casecade is that such a prominent asterism, well-placed in our northern sky, could go unnoticed for so long. A Franciscan monk, Lucien J. Kemble, discovered it in 1980 and it's now featured in Gary Seronik's "Binocular Highlights" and Stephen. J. O'meara's "Hidden Treasures. " The beautiful double, however, is not mentioned in Seronik's book because it won't be seen with ordinary binoculars. However, point a small telescope toward's this celestial waterfall of magintude 9 and 10 stars, trace the stream to the "bottom," and you find a little circlet of stars to one side, and a small cluster - NGC 1502 - to the other.

This cluster has been known for centuries and ocmmented on by other observers. I can only assume they were using telescopes with relatively small fields of view and so missed the more fascinating cascade, though you would think it would have shown in their finders. In any event, O'Meara describes the double this way:

"Through the 4-inch at 23X, a brilliant double star (ADS 2984AB) shines like a finely cut topaz near the cluster's center. Both components shine at Magnitude 6.9 and are simply mesmerizing."

It's fun to read about these things. It's more fun to discover them yourself.