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ginger

So which end of these things do I look into?

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Hi there,

Just bought a set of Binos (8*56 Pentax) hoping they'd be good enough to see a few things. General advice seems to be 10*50s but these were a bit of a bargain so I couldn't resist :)

I'm based in salisbury and hoping to get up to the pepperbox at some point for some proper darkness - wondered if old sarum would be OK for looking north as well?

Seen there's a star party in August so depending how I get on I might swing by that as well.

Ginger

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Hi ginger, welcome to SGL.

Sounds like a nice set of Bino's. The magnification difference between 8x and 10x probably won't be noticed, the objective aperture of 56mm is actually better than the recommended 10x50, and therefore they'll gather more light.

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:) Hi and welcome to SGL, Ginger.

The 8x56's probably gather more light than you're able to use, but if they were a bargain it doesn't matter. If you take the larger number (56) and divide it by the smaller number (8), you get the bino's exit pupil, which is 7mm. That's how large the opening is in the eyepieces where the incoming light passes through before entering your own eyes' pupils. The larger the number, the more incoming light.

More isn't necessarily better, though. Most of us don't dilate to 7mm, which is why the 10x50's are so popular. When shopping for binos it's a good idea to get a pair whose exit pupil matches the size of your own pupils when they're fully dilated, otherwise it's money wasted on optics which are bringing in unusable light. Wish I'd known all this when I purchased my 11x70's, lol.

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Thanks for the welcome.

I'm not sure quite what I'm going to be able to see through these things - I'm planning on looking for jupiter when it's up, saturn and the moon of course - what else can I expect to see?

Also, with the exit pupil issue - how does this manifest itself - does it mean I simply won't get the full benefit from the increased apeture? And how do I measure my dilated pupil... if it's dark enough to be fully dilated I won't be able to see in the mirror?

Ah well, I'm gonna go have a look this evening and see what I can see

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Yes exactly, Ginger.. you won't get the full benefit of the incoming light.

Amateurs have tried various ways of measuring their exit pupils but the one which seems easiest and most intuitive is explained at the bottom of this page. To be honest I've never tried it myself but have heard it works well.

Regarding what you'll be able to see (or to share what you've seen), please stop by our Binocular Forum.. lots of great advice to be had there. :)

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Hi Ginger,

A warm welcome to SGL, binoculars are good way to start, you might also like to download some star maps to help find your way about such as, Stellarium, Cartes du ciel and TUBA, the latter is dedicated to binoculars and can be found through Phil.S.Harringtons web site. Whatever you do enjoy the forum.

John.

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Hi Ginger and welcome from another who likes to grab the bins,

just waiting for some good clear nights when i'm not working to use scope,

as mentioned download stellarium etc as it will help identify what you are looking at,

regards ron.s.g

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