Wednesday, January 18, 2017

revisited M67 (Halifax)

I added the open cluster M67 (NGC 2682 or King Cobra) to my imaging queue for the BGO robot as I could only find one log entry for the Messier. Wanted to visit it again. Also, the loose cluster in Cancer is filled with double stars! A good target for a Moony-sky.

Messier 67 with many double stars in luminance

Luminance only, 30 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

I can see a lot of pairs and multi-star systems including BKO 37, BKO 35, BKO 38, CHE 118/BKO 36 (triple), BKO 39, CHE 119/BKO 40 (quadruple), BKO 41 (trip), BKO 45, CHE 126/BKO 47 (trip), BKO 43, CHE 127 (trip), CHE 125, EX Cnc/CHE 123/BKO 46 (trip), CHE 122, CHE 121/BKO 42 (quad), and CHE 120. I found I had to annotate them to keep track.

BKO 41 is a triple, according to SkyTools 3 Pro, but I cannot spot the C component. The BC separation is just over 2 seconds of arc which is below the system resolution.

Variable EX is the primary element of the triple with EW as the B star.

Wow.

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multi-stars in M67 annotated

I'm still kind of amazed that the interesting dipper-shape pattern between BKO 41 and CHE 119 is not identified as a multi-star system...

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