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Binocular question


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I'm thinking of buying some bins to accompany my telescope and was wondering whether to buy porro-prism or roof prism? If I went for the more compact roof-prism design, are phase corrected prisms essential for light astronomy use / general observing or are they a must?

Thanks in advance.

Richard.

:icon_salut:

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Personally I'd go for a good pair of 10x50s.

I have a pair of Nikon 10x25 Sportlites (£60) that are excellent, even for night viewing but they are not as good as my 10x50 Rocktrails (£13.99) that came from Lidl for night viewing. Due to the much bigger objective optics these have a much better FOV and a much brighter image so you can see much more.

Only my opinion of course.

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Richard

This all depends on how much you would like to spend

at the moment FLO have Celestron Skymaster 15x70 for £49.95 and you know how much people think of them here= A1

the overall winner in the Sky at Night dated May 2010 was Hellios Fieldmaster 7x50 Bak4 FOV 6.3 price 49.99

The Strathspey marines 10x60 are great I have a pair and IMHO there great www.strathspey.co.uk

hope this helps let us know what ones you get :icon_salut:

Doug

Essex

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Thanks BazMark and Doug.

Some interesting comments there, but that doesn't really help me much. I like to more modern roof-prism binocular design, but if I get a pair of those then I wanted to know if phase correced prisms are essential; I also don't want anything too heavy so anything bigger than 10x50 is a no no.

I was originally thinking of just getting a cheap pair, say from scopesnskies.com as they seem to sell a wide variety of bins, and I noticed a pair of 10x50 bressers with an accompanying star chart, book and red flash light all for under £50! :icon_salut:

Are these any good, see here... Bresser Bresser 10x50 astronomy starter kit

Thanks again.

Richard.

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I have an older Bresser and it has been my binocular workhorse for years, until I got my 15x70. I find Porro prism binoculars more comfortable, because they are wider and shorter than roof-prism designs with the same specs. The increased length tends to make them a bit more wobbly. It is also easier to get cheap Porro prisms working nicely. My experiences with cheaper roof prism binoculars are "mixed" to put it diplomatically.

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I have a couple of pairs of the Bressers and they go for around £20 in the right places. For that, you get a bliistering bargain but not a pair of Leicas! Ours get lots of use here and no complaints. Can't open your link though, I'm afraid.

If you want to use them by day avoid the marines with individual focus which would be a nightmare for catching a passing eagle...

Your original question; roofs for a given image quality, cost more. I don't know how important the phase correction would be but I suspect 'very.' If you want the best optics at a lower price then I would say go for porros. Check out the FLO site for some good options and a reliable supplier. Read the last sentence twice...

Dead set on 10x? That's what I have but 8x is very steady when tired. That's just a personal thing anyway.

Olly

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If you want to use them by day avoid the marines with individual focus which would be a nightmare for catching a passing eagle...

Olly

Absolutely true, but marines keep focus MUCH better on the stars! One annoyance I have with both binos I have is that if my glasses knock one of the EPs accidentally, I lose focus in at least one eye.

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Roof prism bins are "neater" but you pay a lot for the privelege. Porro prism bins almost always perform better than roof prism bins of the same specification, unless you pay at least 5x as much ... a good pair of 10x50 roof prism bins will set you back around £1000 but you can get a good pair of 10x50 porro prism bins for not much more than £100.

Yes, with roof prism bins, phase coating makes a difference, I've never found a pair that are even acceptable for astro work that doesn't have phase coating.

Those cheap 10x25 roof prism "sports" bins are a total joke. Forget them. Porro prism bins at the budget end of the price range are often unsatisfactory (slop in the focusing mount, collimation errors) but you might be lucky and get a usable pair. Going up to £80 - £100 more or less guarantees that you won't be disappointed.

You have a scope already so you want a binocular with a low magnification - 1/5 or 1/6 of the objective diameter size - 8x40 or 10x50 are handy for general purpose work as well (sports, bird watching). Since you have a scope already I wouldn't reccomend going any bigger than that (weight, bulk makes them less useful for other things).

Get a tripod adapter (if the bins don't have a tripod bush built in) and a good, rigid tripod to support them. For astro work, hand holding binoculars more powerful than about x8 is not effective, even if they're "comfortably" light and even if you find them usable hand-held in daylight - your eyes work more slowly in dark conditions and "wobbles" reduce both definition and effective light grasp.

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I think your original question roof prism V porro prism, went some way to be answered in this months S@N mag, where they reviewed both types, it would seem there is little to choose between them now for Astronomical purposes.

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The Bresser you mention can be had for £25 ish from Telescope House. I have a pair my wife bought for me a couple of years ago. They are great for birding - saw my first Spoonbill on my first outing at Langstone Harbour with them! - and good for star gazing too.

They can be picked up cheaply from Lidl on occasion, but herein lies the collimation issue. A bit more from Telescope House and you should be ok. Mine are perfectly collimated with no slop at all and the peace of mind that they could always have gone back in needs be.

I also have a pair of 8x42 Opticrons as well, which are great for both purposes too. Both of mine are porros. I find them cheaper to purchase initially (although the Opticrons were given to me) and more robust.

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Apologies. I misunderstood your question.

Having done a little reading on Phase corrected prisms I would say that it's not essential as my Nikons which use roof prisms and can't be PC for the price they were, produce very clear night time images. Where they fall short however, is brightness of the image but then they weren't designed for astronomy use. However, if I were to want a larger pair of roof prism binos I would opt for at least a 40mm OL and I would want to try them first.

This site made interesting reading:

Binocular Prisms: Roof or Porro?

The Bressers you mention would probably be fine (Lidl sell them from time to time too for about £15) but I would read the Supplier Review section of this forum before purchasing from the site you mention as many including myself have had real problems with them. My case, which involved a pair of £30 binoculars and began last December was never resolved.

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Personally I'd go for 10*50 porro prism bins if your using them with a scope, because with the larger models like 15*70 you WILL need a tripod. Plus as said above roof prisms tend to be optically inferior to porro prisms.

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