Cancer's Sigma Doubles

[cloudsweeper]

(Bayer designation, lower case Greek, brightest stars.)

Sigma 1 - 4 fall within about 2deg of field.  I tried for these yesterday with the Dob and failed miserably - conditions (lack of darkness for naked eye spotting, outside lights, some cloud) conspired to stop me from getting a fix on anything in the region.

So at 8.45 this evening, I set off with the 8SE GoTo.  There were some clouds, and the sky was darkening - Pollux, Castor, and Procyon were clear.  I aligned on P and P.

Sigma 1 Cnc - a double - details vary between printed, online, and planetarium sources.  GoTo put me bang on it (using the SAO number) with x42/1.94deg.  There was an "arrowhead" of stars, with Sigma 1 on the baseline.  The fainter companion at an easy 77" (ref Haas) was very clear, not as sharp at x106, better x71.  I wonder if this is in fact an optical pairing?  I saw no sign of another, fainter companion at 5.2" (ref Sky Safari).

Sigma 3 Cnc, Sh 100 - a triple - 90" and 156".  Bang on again - I saw an inverted "L", with the primary at the corner.  The fainter companions were again very easy (x42).  Noticeably, the one at 90" did not feature in Stellarium.  

Sigma 4 Cnc, 66 Cnc, Sigma 1298 - latter Sigma being upper case, as used in the FW von Struve catalogue of doubles.  It was getting cloudier by now, but I still got the faint, close secondary at a separation of about 4.3" using x71, better at x106 this time.

Sigma 2 Cnc - not a double.

As clouds thickened, I finished at 9.30, after a quick look at the lovely M44 Beehive Cluster.  Although brief, this was a most satisfying session, and I confess to having greatly enjoyed the speed and convenience of GoTo and its associated tracking.

Doug.

[cotterless45]

Nice , don't forget to catch Zeta Cancri , Tegmine , SAO 97645. A lovely gem of a triple , showcase . There are a whole gamut of binaries in M44. SLE 337, SLE 336. Σ 1249, SLE 332 and Σ 1254. All these are wide and add to the buzz of the beehive ,Nick.

[cloudsweeper]

6 hours ago, cotterless45 said:

Nice , don't forget to catch Zeta Cancri , Tegmine , SAO 97645. A lovely gem of a triple , showcase . There are a whole gamut of binaries in M44. SLE 337, SLE 336. Σ 1249, SLE 332 and Σ 1254. All these are wide and add to the buzz of the beehive ,Nick.

Thanks Nick.  Yes, the showcases never fail to please.  And the "Cinderellas" usually make for interest and good viewing too of course!

Doug.