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Hi, been using binoculars for nearly 2 years & want a telescope but I find it uncomfortable looking through one - binoviewers seem like the answer - do they degrade or darken the image? I don't believe in free lunches. I will be spending about 1K on either: a 100ed refractor on a EQ5, a 150mm Mak Cas on a EQ5 or on a 10" flex tube Dob. Are any of these 'scopes more suited to binoviewing?

How much should I spend on a binoviewer & can anyone recommend a suitable model?

Thanks again.

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they tend to be better for moon and planets cos they do darken the image a little. the mak cass will work best - with the others you might have trouble achieving focus without barlows and that wil give very very high mags which you might not want. the newt will probably work worst and will effectively be "stopped down". I suspect all the cheapy ones are much the same although the williams optics ones consistently seem to get good reviews.

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Binoviewers are brilliant in a Mak or Sct and the WO bv's are superb value for money. I didn't try them in a refractor yet but (as stated above) you may have focusing issues in a dob.

In my Sct it feels like you're flying a few hundred feet above the surface of the moon, planets look allmost 3D, and the benefit of using 2 eyes makes starfields totally immersive. Next best thing to an Ethos imho :)

(tip - get winged eyeguards for them - makes a huge difference)

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I've got the WO binoviewers for my SCT and don't need to use the supplied barlow to get focus. Agree with the others that they really come into their own with planetary viewing where the views really are are incredible, but I do find the views too dim for my liking when observing DSOs.

Brantuk / red dwarf - I haven't got any winged eyeguards myself - be interested to know what they're for.. and where I would get them from? Thanks :)

Matsey :)

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the mak cass will work best - with the others you might have trouble achieving focus without barlows and that wil give very very high mags which you might not want.

Not true :) Work the maths! :)

The Barlow will slow the F-Ratio of a Newt to be similar (or even less) than the Mak, which results in similar magnification:

127mm F12 Mak + Bino + 26mm Plossls = 58x magnification

130mm F5 Newt + Bino + 2x Barlow + 26mm Plossls = 50x magnification

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Brantuk / red dwarf - I haven't got any winged eyeguards myself - be interested to know what they're for.. and where I would get them from? Thanks :)

Matsey :)

you can buy them from here, winded rubber eyecups, they really do help keep out the light from the sides when using them with binos.

Skywatcher Eyepiece | Diagonals and Filters

sherwoods, about halfway down the web page.

hope it helps

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Not true :) Work the maths! :)

The Barlow will slow the F-Ratio of a Newt to be similar (or even less) than the Mak, which results in similar magnification:

127mm F12 Mak + Bino + 26mm Plossls = 58x magnification

130mm F5 Newt + Bino + 2x Barlow + 26mm Plossls = 50x magnification

incorrect G-B due to the positioning of the barlow its effect is increased . there are a number of threads on this here and on CN. Plus, have you backed up your "theory" with observation? i have and i can assure you it is true :)

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incorrect G-B due to the positioning of the barlow its effect is increased

Oh dear...

Well if you will go sticking a normal Barlow in that position, what do you expect? :)

I'm talking about using the correct (e.g. William Optics) Barlow that's designed specifically for 1.6x / 2x magnification in conjunction with a binoviewer.

Sorry if that was unclear :)

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Oh dear...

Well if you will go sticking a normal Barlow in that position, what do you expect? :)

I'm talking about using the correct (e.g. William Optics) Barlow that's designed specifically for 1.6x / 2x magnification in conjunction with a binoviewer.

Sorry if that was unclear :)

oh dear oh dear,

I love it when people say "sorry if that was unclear" when what they actually mean is "sorry I actually said something completely different":):) . perhaps someone who actually has the WO binovewers can comment as to whether it's just a regular 1.6x barlow or a barlow that gives 1.6x when stuck at the end of a pair of binoviewers (and if the latter I suspect it still won't come to focus in most newtownians and many refractors).

ps you didn't answer the question as to whether you'd actually backed up your "theories" with observation. hmmm. are you a policitician? :)

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I love it when people say "sorry if that was unclear" when what they actually mean is "sorry I actually said something completely different"

Well I kinda assumed no-one would take it to mean "Use an unsuitable Barlow designed for a completely different purpose" - but I appreciate it would have been technically more accurate if I had said "OCA" or "OCS" rather than "Barlow" - but since sales material for the William Optics Binoviewer often refers to the OCA as a Barlow I thought I'd use this more common terminology. Sorry if that was unclear :)

Anyway, you asked if I'd made any such observations, and - owning both the WO binoviewers and OCAs - yes I have.

In the case of the 1.6x, yes - you are quite right - this alone is not enough to bring it to focus in (e.g.) a 130P. I can't remember whether I needed just the extension nosepiece or the 2.0 OCS as well to bring it to focus, but either way, it's still no more magnification than you'd get with the Mak as explained in my previous post. I didn't measure it accurately since - from observation - it was functioning as expected.

With regard to the specific magnification that these Barlow / OCA lenses have, I was interested in the differences that I'd achieve with a Mak 180, since the change in focal length caused by the Maks focussing mechanism would impact the magnification somewhat as well, and I wanted to know exactly what to expect, since this was uncertain, and this is my main planetary instrument.

The results were as follows:

(in a Skymax 180 Mak Pro - other Maks may be different)

Bino with no WO Barlow: mag x 1.2

Bino with 1.6x WO Barlow: mag x 1.75

Bino with 2.0x WO Barlow: mag x 2.12

- just to be "clear" :) the "1.2" above is caused by Mak 180 focus-shift, as are the deviations from spec in the bottom two.

Hope that helps.

rgds, J.

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Well I kinda assumed no-one would take it to mean "Use an unsuitable Barlow designed for a completely different purpose" - but I appreciate it would have been technically more accurate if I had said "OCA" or "OCS" rather than "Barlow" - but since sales material for the William Optics Binoviewer often refers to the OCA as a Barlow I thought I'd use this more common terminology. Sorry if that was unclear :)

Anyway, you asked if I'd made any such observations, and - owning both the WO binoviewers and OCAs - yes I have.

In the case of the 1.6x, yes - you are quite right - this alone is not enough to bring it to focus in (e.g.) a 130P. I can't remember whether I needed just the extension nosepiece or the 2.0 OCS as well to bring it to focus, but either way, it's still no more magnification than you'd get with the Mak as explained in my previous post. I didn't measure it accurately since - from observation - it was functioning as expected.

With regard to the specific magnification that these Barlow / OCA lenses have, I was interested in the differences that I'd achieve with a Mak 180, since the change in focal length caused by the Maks focussing mechanism would impact the magnification somewhat as well, and I wanted to know exactly what to expect, since this was uncertain, and this is my main planetary instrument.

The results were as follows:

Bino with no WO Barlow: mag x 1.2

Bino with 1.6x WO Barlow: mag x 1.75

Bino with 2.0x WO Barlow: mag x 2.12

- just to be "clear" :) the "1.2" above is caused by Mak 180 focus-shift, as are the deviations from spec in the bottom two.

Hope that helps.

rgds, J.

G-B, I am glad that with my patient guidance you have managed to clarify what you meant :) and I must admit I didn't know that the WO 1.6x barlow is not actually a 1.6x barlow at all (although still not completely convinced of that). :)

off to lunch (humble pie):)

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didn't know that the WO 1.6x barlow is not actually a 1.6x barlow at all (although still not completely convinced of that).

By comparison, the (similar-looking) nosepiece from a Revelation Eyepiece Kit Barlow (2x) can be seen to have a much stronger lens then either of the William Optics OCAs. For experimentation, I've sometimes tried to use that on the nose of the Binoviewer, but as you've said in your earlier post, it just leads to ridiculous magnification.

When these clouds clear I'll post some Newt-based measurements for reference.

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This is interesting. If the OCA of the WO binoviewers really does introduce so little relative amplification, they would be the ones to go for, saves buying the more expensive Denk types :). It all depends on the "stength" of the Barlow in use, modern Barlows are pretty short focus so that they can be used in a minimal length tube. I experimented with one of the old Vixen .96" 2X Barlows which because of their long focal length gave minimal amplification with just the lens itself screwed into the binoviewer eyepiece.

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The trouble with the William Optics OCAs however (both the supplied 1.6x and the optional 2.0x) is that the inside of the black barrel is very shiny. This doesn't seem to matter on Jupiter, but - in my scope - on the moon, you get dreadful flaring across the dark sky when looking at the moon's terminator. It's for this reason I've just bought another pair of brand-new eyepieces this week, so I can look at top magnification at the moon, without using either of the OCAs.

It's a shame really - I suppose an experienced DIYer could remove the lenses, spray the assembly matt black and put it back together again, but I've got too many household jobs to account for before I can be caught spending time on something like that! :)

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I've got too many household jobs to account for before I can be caught spending time on something like that! :)

Hide it behind the toilet and do it in stages :)

"rattlerattlerattle PSSSSSSSHHHTT"

"Whats going on in there? You've been in there 30 minutes! Are.. Are you spraying something?"

"Nothing dear, must've been a dodgy bit of toast for breakfast"

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Hide it behind the toilet and do it in stages :)

"rattlerattlerattle PSSSSSSSHHHTT"

"Whats going on in there? You've been in there 30 minutes! Are.. Are you spraying something?"

"Nothing dear, must've been a dodgy bit of toast for breakfast"

:)

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