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Great Double 57Cnc & 7 More In Cancer


cloudsweeper

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7.20pm, Wednesday, still, mild, clear. 8SE with Focal Reducer, on GoTo. Aligned on Procyon (only).

Σ1322 - 8th mag pair, 1.7” sep. x36 > x191, possible split, clearer at x 213 in moments of good seeing. Very close, well matched, sec at 2 o’clock.

Σ1276 – another 8th mag pair, much wider at 12”. (Not in handset, went via A2Cnc.) Part of a lozenge-shape of four. Just got the split at x36. Good match, one above the other.

OΣΣ97 – yet another 8th mag pair, perfect match, 52”. (Via 75Cnc.) Very easy of course at x36, stars side-by-side.

Σ1332 – mags 7.9, 8.1; sep 5.8”. (Via 6LMi.) x36 > x73, components close, matched, sec at 2 o’clock.

Σ1245 – quadruple system (2) + (2), visual double, 6th and 7th mags, 9.8”. Very good split at x191, slightly fainter sec at 1 o’clock.

(Σ1171 - 6th and 10th mags, 2.1”. No success here, even up to x213 – large Δmag and very faint sec.)

The fine Tegmine (16Cnc) – this is a system of nine, although not all members are physical. The A, B, and C stars however are gravitationally bound. AB: 5th and 6th mags, sep a tight 1.1”. AB-C: 4th and 5th mags, 6.3”. I easily split the AB-C pair at x191, with the slightly fainter component at 2 o’clock. The AB pair however did not yield their prize – conditions and aperture were not up to the task, despite trying at x320, by which point there was loss of sharpness.

OΣΣ96 - 7th and 8th mags, superwide 50”. Not a physical pairing. Very easy at x36, fainter star at 11 o’clock.

57Cnctriple, with mags 6.1, 6.4, 9.2, and seps of 1.5” and 54”. This was the highlight of the session, and the closest sep I was able to resolve. It is part of a long curve of stars. At x36, the 9th mag component was easily seen, sitting at 7 o’clock. Next, the tricky part. I went up in stages to x256, and got the split – very close – two bright spots in the general glare and rings. Pleasingly, those spots were still sharp, showing once again that the Focal Reducer really does sharpen up the view in the Cat. The two were well matched, with the sec at 4 o’clock. I even got the observing chair out to sit and enjoy the spectacle in comfort! I tried x 320, but sharpness was again lost at that magnification.

I finished after 90 minutes, having had a great run, with some very pleasing targets.

Doug.

 

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Well done Doug I went in the yard looked up could see 5 stars of Leo and could not see Orion`s Sword it was that milky, over the top of my house Cassiopeia was supposed to be there but that milky could not see one star.

Nice getting Tegmine I believe this can be split in a 4" but I have only done it in a 5"  I will check those doubles to see if I have done them before if not I can add to my lists thanks for posting.

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2 hours ago, wookie1965 said:

Well done Doug I went in the yard looked up could see 5 stars of Leo and could not see Orion`s Sword it was that milky, over the top of my house Cassiopeia was supposed to be there but that milky could not see one star.

Nice getting Tegmine I believe this can be split in a 4" but I have only done it in a 5"  I will check those doubles to see if I have done them before if not I can add to my lists thanks for posting.

Thanks Paul.  The sky here is also poor, which is why I opted for GoTo.  Had a go with the Dob recently and didn't find much!

Splitting tight doubles with a small aperture depends very much on the seeing, so I generally use 8 or 10 inches of aperture for that.

Doug.

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Thank you for an enjoyable observing report.  I was out last night as well with a 5” refractor.

Tegmine AB I could make out as binary but with out a clean split at X225.
57Cnc slit cleanly at the same X225 and a lovely sight.

I think I was somewhat luckier here in Suffolk as the sky was not as milky as others have reported.

John

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6 hours ago, OK Apricot said:

Thanks for your report, what you saw is well described 🙂 I must take a look at this Tegmine soon, it sounds like a gem. 

Yes, Tegmine is a nice (and rather tricky) triple.  It might be a system of nine stars, but visual observers will not make them out of course.  57Cnc is not "promoted" as much as Tegmine, but I found it a more pleasing target, with a beautifully near-matched close pair, all in an attractive stellar setting.

Doug.

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