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CESDewar
GorillAstronomer
Reged: 01/16/05
Posts: 1679
Loc: Morganton, GA, USA
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Someone PM'd me and asked me to post about the other double-double in Lyra since I had responded to a post on another forum about this pair.
Lyra is well-positioned for viewing right now (look towards the East at around 40° elevation at around 10pm from most Northerly latitudes). Many observers know about the famous Double-Double in Lyra (Epsilon Lyrae) and while the secondaries of each double are not a binocular target (except in my Saturn III's at 150x!), it still makes a fine view at lower power with Vega and Zeta Lyrae (aka "the false double") with a 3° FOV or better. Zeta Lyrae at around 43" separation is a nice target in binoculars and shows well in my 11x56 Garrett's.
The other double-double may not be quite as well known, but it is actually a finer target in large binoculars. In this case, the two primaries (mag. 7) have a separation of about 10'30" and the secondaries (mag 8) are around 13" and 15" respectively - reasonable targets for larger binoculars. I can just split these handheld in my 18x50 Canons, but they are a particularly fine sight in my 30x77mm binoculars. The PA's on each pair are similar, with the slightly fainter secondaries positioned towards Sheliak.
If you have a larger pair of binoculars (certainly 15x70's would be big enough), this is a fine pair to scout for. Let us all know what you think about it!
A finder chart is attached here.
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Edited by CESDewar (06/21/08 10:45 PM)
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GlennLeDrew
sage
Reged: 06/18/08
Posts: 286
Loc: Ottawa, Ontario, Canada
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About a decade ago I stumbled on this one quite by accident. I was trying to sweep up the Ring nebula with a 5" f/5 binocular I built for a buddy, and when this "pair of pairs" drifted into view I had to blink my eyes a bit because I really thought I was starting to see double!
But this duo is a really neat sight due to the similarities; separation, position angle and component brightnesses. In other words, kind of like clones of each other. They're cataloged as Struve 2472 and Struve 2474, if memory serves.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 5538
Loc: Pennsylvania, USA
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The proper designation is Struve 2470/2474.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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SaberScorpX
Post Laureate
Reged: 01/12/05
Posts: 4077
Loc: illinois, usa
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Another look and the DSS plate:
http://tinyurl.com/6xqvmn
Stephen Saber
PAC/Astronomical League
www.astronomyblogs.com/member/saberscorpx
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Special Ed
Post Laureate
Reged: 05/18/03
Posts: 3434
Loc: Greenbrier Co., WV 38N, 80W
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CESD,
I took a look at Struve 2470/2474 this evening with my 15x70's on a p-gram mount. The "other" double-double was easy to find using your chart. I could *almost* split the easternmost pair (Stuve 2474) and could definitely see an elongation at about PA 270°. I couldn't make out any elongation for Struve 2470. The seeing may have been a factor--I took a look at M57 before I looked at the doubles and The Ring kept popping in and out of view. Maybe next time the seeing will be better. 
Thanks,
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Michael Rosolina
8" f/10 Orange Tube SCT
4.25" f/4.2 Astroscan Reflector
SVP 3.6" f/13.6 CA Reflector
40mm PST f/10
APM Germany HD 15x70 binoculars
Canon 12x36 IS II binoculars
Mark I Eyeball
My CN Gallery
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ronharper
scholastic sledgehammer
Reged: 02/14/06
Posts: 877
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CESD,
With a 16x70, this is definitely a challenge. I find the southeastern pair is difficult but doable, the other is extremely difficult, I just got it once or twice.
Through a telescope however, this is a unique sight at around 30x. The two doubles are so nearly identical in brightness and orientation that I can hardly tell the difference, yet you still have to scan across a considerable field to view one or the other. It does a funny thing to my head. I look at one, then the other, then the one, then the other, etc. This can go on for a long time before I've had enough!
Ron
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CESDewar
GorillAstronomer
Reged: 01/16/05
Posts: 1679
Loc: Morganton, GA, USA
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Yes it's definitely a challenge object when you drop down to the 15x range. It's a very nice view in my 30x77mm binoculars, and I can just split it in my 18x50 IS Canon's handheld, although it's borderline.
The separations are around 13" and 15" (I see an earlier post listing it at 14" and 16" - this may be choice of rounding or truncating the fractional part).
There's another thread here about splitting 100Hercules which is a 14" separation that I was just barely able to catch in my 11x56mm Garrett's (possibly 11.75x?) but which I could not split at 10x although two other posters claimed to catch it at 10x and even 8x.
But the secondaries here are quite a bit fainter too. I still think though it should be do-able with 15x under good viewing conditions. Perhaps some other viewers can take on the challenge and report their results! I find objects like this to be an ever-entertaining aspect of binocular observing.
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Dis
member
Reged: 03/04/08
Posts: 23
Loc: Sonoran Desert, AZ
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I'll have to give it a go in the next few nights. Thanks for pointing this out and creating the chart.
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Nikon Action Ex 7x50
Orion Resolux 15x70
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