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10x42 or 8x42 for stargazing?


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For a given aperture, should I go for exit pupil or magnification?

If I were set on getting a 42mm binocular, am I better off getting an 8x to maximize the exit pupil, or going 10x to see deeper?

I know that 10x50 is often cited as the ideal, but I think 50mm is going to be too big, and while I am sure the extra 8mm helps, I’m hoping that it is not going to make too much of difference because I don’t want to pay the penalty in size and weight.

So then it is either 8x42 with the bigger exit pupil, or 10x42 with the higher mag. Is there an answer that most people lean towards?  

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I have the £16 Lidl's / Bresser 10x 50's (43mm actual aperture) and they are OK for keeping steady without using a monopod or tripod.

They are dual purpose for  nightime / daytime, really easy to use, and lightweight.

However - the stars are fainter and a little washed out compared to the Revelation 15x70's - on Kembles cascade in particular, but also on Pleiades, and the double cluster.

I would go for either - but would err towards 8x if you are limited to 43mm, and 10x for 50mm.

The 8x will give a slightly brighter, cleaner view, and I guess you will see more.

The 10x will offer a little more magnification, but struggle under light polluted skies.

If you can try before you buy, it might help with your decision making process.

Also - try to second guess whether you would want to go for a pair of 15x or 20x bins in the future.

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7x50? Nice widefield with good light-gathering yet also can be smaller than a 10x50...depends on what you want to achieve - wider field or higher mag? Wider field may incur a less-dark background sky...how are the skies in Honolulu? 

Have a read:      

http://stargazerslounge.com/topic/185194-are-quality-7x50-binoculars-a-good-purchase-or-will-i-regret-the-purchase/

Note ollypenrice's post # 12.

Whether there is an all-round cake-and-eat-it solution I couldn't say - 'swhy I have 2.1x 42, 7x50, 10x50 & 15x70. Thinking of a 8x42 also....Glutton? C'est moi. :) 

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The other factor is the jitters. I used to be able to hold 10x without them trembling too much but now I'm older I prefer the steadier image at 8x. I'm not hugely jittery, by the way, and 8x is very popular amongst experienced birders for the steadier view.

Olly

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The other factor is the jitters.

I used to be able to hold 10x without them trembling too much but now I'm older I prefer the steadier image at 8x.

I'm not hugely jittery, by the way, and 8x is very popular amongst experienced birders for the steadier view.

Olly

For those here with unlimited funds, Canon makes the Image Stabilizer models of binoculars. waytogo.gif

http://www.usa.canon.com/cusa/consumer/products/binoculars/image_stabilizer

One way to help overcome the jitters/shakes is to observe the night sky from a comfortable sitting position.

One of my favorite chairs is the inexpensive V-Rocker. gramps.gif

I've been using them, on & off, for approx. 10 years.  

http://www.walmart.com/ip/16472636?wmlspartner=wlpa&adid=22222222227000790424&wl0=&wl1=g&wl2=c&wl3=40845781232&wl4=&wl5=pla&wl6=78659151872&veh=sem

Stan

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Yes, the IS Canons are one way to spend unlimited funds on astronomical binoculars. They are good, too. I chose the other way, in the end, and went for the glass, with a second hand pair of Leica 8x42. I don't use binos in astronomy for magnification since I have telescopes for that. I use them for widefield and the tiny stars and high contrasts of premium optics do it for me. It's a personal call when it comes down to the wire.

Olly

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Larger aperture =  more light capture.

If your maximising your limit to 42mm I would opt for the  exit pupil, to maintain as much brightness as possible from what the 42mm is capable?

If you double your magnification  you will achieve a light reduction of over four times according to the Inverse Square Law. 

Even 10x42, you will be a shade darker than the 8x42.

8x42 will / should offer a brighter, steadier, wider view. Only your eyes and a side-by-side comparison will tell.

I also own  Bresser 'Hunter' 7x50s, had them for Years, but my  Helios 8x40s feel and seem much better, possibly a combination of better glass and exit pupil size, and  I don't favour  my  Revelation 'Astro 15x70s except for day work?

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For me personally, a good 10x50 (by good I mean full aperture) is the starting point for astronomy use. Anything less in my experience just lacks any wow factor? That said, I've never been lucky enough to look through a premium 42mm like Olly's?

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 That said, I've never been lucky enough to look through a premium 42mm like Olly's?

I have. If I could afford to, I'd do it regularly: you just cannot beat good glass. One night a few of us did a side-by-side of a hand-held Leica 10x42 and a mounted Celestron Skymaster 15xso-called-70. This was when Lovejoy was near M79. The globular was easy to see in the Leica; none of us could see it in the Celestron. Couldn't see it in my Opticron 10x42 BGA either, but could in my 10x50 BA8 (easy in the 15x70 BA8).

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  • 3 weeks later...

For a given aperture, should I go for exit pupil or magnification?

If I were set on getting a 42mm binocular, am I better off getting an 8x to maximize the exit pupil, or going 10x to see deeper?

I know that 10x50 is often cited as the ideal, but I think 50mm is going to be too big, and while I am sure the extra 8mm helps, I’m hoping that it is not going to make too much of difference because I don’t want to pay the penalty in size and weight.

So then it is either 8x42 with the bigger exit pupil, or 10x42 with the higher mag. Is there an answer that most people lean towards?  

If I were 'given' the choice..I would go with the 10x ... I have 10x50 that have proven quite usefule for large field DSO's Like M44, M45 or Mellotte20..they do get a bit shakey after a few minutes though..if you can find a pair of stabilized binocs that may help.

I would like to hear other opinions on stablized binocs 

Brian K9WIS

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I really enjoy the view through my Bushnell Legend 8x42, I think they are now called Bushnell Legacy, they are fully multi-coated, waterproof, Bak4 porro prism, twist-up eye cups (which I really like), the focuser isn't the smoothest but it works well so it's easy to achieve focus and keep it.

I have tried 10x50 and 15x70 but just never got on with them, maybe my wonky eyes just can't handle the extra size as I always see two images through anything larger than my 8x42.  Could be a quality thing, but I can't be bothered trying to find out.  8x42 is comfortable to hold up for short periods, I sometimes mount on a tripod (with the larger L bracket for stability) if I am feeling lazy or lunar observing.

A very nice pair of binoculars (really nice thick strap with mine too) for the money at a smidge over £100.

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I have looked through Olly's 8x42, and they are great. I still prefer my 15x70 BA-8 binoculars. More light, and the stars, if not as tight as the Leica, still very tight indeed. I can hand-hold these for quite a while, and 10x50 presents few problems. This is very personal, however, and try before you buy might be the best option. For longer sessoins I use a P-mount (home made).

http://stargazerslounge.com/topic/204423-p-mount-mark-iii-now-finished/

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I think it's as well to try a formal self-test regarding the highest magnification you can usefully hand hold. We can all be deceived by impressions, though I don't think this applies to an observer of Michael's experience. It's dead easy to do: find some distant text at the edge of legibility and try it in different powers. If you really want it to be a tight test, don't try to read the words, rather try to read the letters to yourself in reverse order, starting with the last. This way the brain won't fill in or guess for you.

This test confirmed to me that I had more real resolution in x8 than in x10. But, of course, that's just me.

Olly

Edit. Hand held, that is.

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I love my Helios Nirvana ED 8x42's. Compact and easy to hold steady. I use them for either planning star hops and then using 15x70's on tripod or scope to observe something. The wider field of an 8x Is perfect for this. I'll often just take them out just for some general stargazing - perfect. The ED glass gives lovely sharp stars and no chromatic aberration. I see more with10x50's, but the latter are perhaps the perfect jack of all trades; I prefer the 8x42 + something else combination. I've always fancied a go on the William Optics 10x50 ED's. Enjoy, whatever you choose.

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for my few pence worth - £49.99 to be exact - I went for the Helios Fieldmaster 10x50. They're light and well made and the image is nice and sharp.. and as I mentioned, they're only 50 quid. Good if you're on the tighter budget.

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+1 for 8x42. The x10 doesn't sound like much difference but it means 25% more hand shake. If LP is really bad though the x10s will give a bit more contrast - but if I was going the x10s route I'd also go up to 50mm aperture while I was at it.

It's all down to personal preference and x8 or x10 will be for quick sweeping views for most people rather than the detail you can start to get with 15x70s or 20x60s.. and you do need a minimum magnification to see most deep sky objects - e.g. a great 50mm telescope lens might just show the ring nebula in ideal conditions, dark skies, etc but not at x8 or x10, more likely you'd need x50.

Dave

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but if I was going the x10s route I'd also go up to 50mm aperture while I was at it.

Sound advice, I think, but with one caveat. A lot of budget 10x50s have an effective aperture of 42mm or less (the Strathspey Marine 10x50 is effectively 10x41, the Olivon QB 10x50 is effectively 39mm) - unless you are getting an actual 50mm aperture, the 10x42 will be a better choice as it will be lighter and smaller for the same aperture.

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I have the opticron 10x50 - they were on a good price from FLO.

I find they are manageable handheld if scanning the sky. I get more pleasure from putting them on the tripod as that enables a longer more relaxed viewing session - with more precise viewing without any shaking if you try and hold on one section of sky.

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