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Need Help 4 Project: Owners of multiple binoculars

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#1 Urban Observer

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Posted 19 January 2013 - 08:43 PM

There is a project, currently in "the works"...
It is: To produce and provide binoculars, with GCE Nebula Filters installed inside the eyepiece barrels.
I'm very excited about this potential new product :) In fact, whenever I use or even think about Binos w/ nebula filters, I get all giddy inside :jump: And, I'd like to see this idea become a reality. "We" are trying to find binoculars that meet the following criteria:

Size: 10x50 or larger preffered
Price range: ~ $200 preferred
Mechanical: Eyepiece optics must be easily accessible. i.e., relatively easy to disassemble/re-assemble the eyepiece barrels.

This last criteria is important. I should also point out, in case anyone is curious: That, yes, EdZ :bow: has been consulted about this already.
What we need now, are some owners of multiple Binos to make some (informed) suggestions...
:question:Which (currently available) binoculars do you think would be perfect for this project?

Below, are just some models that I've been thinking of. Since I don't own any of them, I can't determine if the EP barrels can be disassembled, etc. :confused:

The difficult challenge we face, is to choose one model...out of all the possible prospects :help:

After all, "There can be only one"

Orion UltraView 10x50 Wide-Angle Binoculars
Nikon 12x50 Action EX Extreme ATB Binocular
The Garrett -or- Oberwerk 15x70's might be good?

I will post updates, of any progress that is made.

P.S. I may be wrong, but I don't believe that Pentax Binos are good candidates. Due to their unique eye-cups.

Thanks!
-Al

#2 Mark9473

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Posted 20 January 2013 - 02:39 AM

Since Harry Siebert appears to be able to install new (better) eyepieces on several binocular lines, the problem may not be a big as you think.

Am I correct in thinking this brings the eyepiece out a bit? If so, make sure you take a model with very long eye relief to start with.

#3 GlennLeDrew

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Posted 20 January 2013 - 03:38 AM

If using ~27mm diameter filters, the eyepiece barrel must be large enough to accommodate the filter, the latter of which which likely will best be removed from its cell. This will probably limit to wider field models of bino, which tend to have physically large eyepiece assemblies.

The filter will move the focus, and hence the eyepiece, farther back by a distance about equal to 1/3 the filter's thickness. While small, this effect is nonetheless worth bearing in mind.

A worthy project! In spite of the misplaced concerns of many who seem to believe that only large apertures are useful with nebula filters, I can state unequivocally that 50mm apertures are eminently useful, even with narrow-band UHC and O-III types. All aperture does is to controll how small an object can be detected. There are a good number of interesting objects large enough for a 10X50 or similar bino.

#4 daniel_h

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Posted 20 January 2013 - 05:51 AM

The GO SS or Obie ultra might be a go if the larger ep's will fit as if I remember some of the big models come with threaded ep for filters, I tried to get my local retailer to get me one ep from united optics, am waiting for the order to see if I can get one to replace on one eyepiece so I can use a filter

#5 Urban Observer

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Posted 20 January 2013 - 06:54 AM

Thank you very much for all the replies so far! I hope to get some more.
* I should point out that the filter manufacturer is able to cut the filter element to the needed diameter * Such as 21mm for the Barska X-Trail, just as an example.

I believe we have a real shortage of Binos with threaded EPs...And, at the same time: Filter elements installed inside the EP's have recently been reported to work nicely (on one of the 1st prototypes) :)

Thanks again, All!

Thanks again!

#6 EdZ

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Posted 20 January 2013 - 07:36 AM

The difficult challenge we face, is to choose one model...out of all the possible prospects

After all, "There can be only one"

Orion UltraView 10x50 Wide-Angle Binoculars
Nikon 12x50 Action EX Extreme ATB Binocular
The Garrett -or- Oberwerk 15x70's might be good?



I would NOT choose a binocular that is a single in a model line.
The Nikon AE 12x50, 10x50 and 8x40 IIRC all use the same eyepieces, so sizing for tat model line gives three choices.
If you choose a waterproof nitrogen filled binocular, you have the added expense of recharging them after you open them up.

It seems the intent is to permanenntly mount the filters inside, not to be removable by the consumer. that means forever after you are limiting the use of that binocuular to nebula observing. Frankly, that might steer some people away from it as too restrictive a use.

Quite a few years back, I replaced the eyepieces on my Oberwerk 15x70 LER (the $150 model 15x70). If I'm not mistaken, that model line has similar parts through other sizes, like the 12x60. Removing and replacing the eyepieces is a quick and easy job.

That's a fairly wide angle eyepiece at Afov=64°. The inside of the 15x70 eyepieces has a retaining ring that screws in to hold the lens assembly in place. That retaining ring is plastic and has the field stop, a fs clear aperture of 21mm. When that retaining ring is removed the inside of the lens housing is threaded and it is very close to 26mm in diameter. So the retaining ring with field stop could be removed and a filter could be threaded to match the 26mm threads, then becoming the new retaining ring in the eyepiece barrel, but you'd lose the field stop. However, I'd guess the substitute ring you would use would potentially be sized to act similar to the removed field stop.

These eyyepiece sets are available from Oberwerk as aftermarket replacement eyepieces. You could very easily obtain a set of these eyepieces to test with. If it works, you don't need to sell whole binoculars, you can sell aftermarket replacement eyepiece sets. Based on how many other companies sell what appears to be a similar if not thee same model binoculars, this approach would reach a much broader existing owner base. That would have the added benefit that owners, buying alternate nebula fitted eypiece sets, could change back to the clear eyepiece set anytimee they want.

edz

#7 Jon Isaacs

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Posted 20 January 2013 - 09:51 AM

It seems the intent is to permanently mount the filters inside, not to be removable by the consumer. that means forever after you are limiting the use of that binocular to nebula observing. Frankly, that might steer some people away from it as too restrictive a use.



That would be my concern. Add to that, the problem of choosing the right nebula filter, O-III, H-Beta, Ultrablock/True UHC?

That would have the added benefit that owners, buying alternate nebula fitted eyepiece sets, could change back to the clear eyepiece set anytime they want.


That seems like an interesting alternative. Along this same line of thinking, how about filters that fit between the observers eye and the eyepiece? With a long eye relief binocular or with individual eyepieces, a set of filter pairs of the different types would allow the filters to be easily changed without disassembling the binoculars. One could even design the external filters to fit the eyepiece cups of popular models of binoculars. One would be out of the filtered binocular market and into the filters for binoculars market.

Jon

#8 EdZ

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Posted 20 January 2013 - 10:00 AM

Well that option already exists. The Garrett Signature binoculars are fitteed to put filters behind the eyepieces. Two probllems with that appraoch. It really cuts the eyee relief to extremely shhort. It's tthe wrrong place to put a filter.

edz

#9 Jon Isaacs

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Posted 20 January 2013 - 10:27 AM

Well that option already exists. The Garrett Signature binoculars are fitted to put filters behind the eyepieces. Two problems with that approach. It really cuts the eyee relief to extremely short. It's the wrong place to put a filter.

edz


Ed:

I understand the issue with the eye relief but a carefully designed filter could overcome this difficulty for binoculars with sufficient eye relief.

As far as it being the wrong place to put a filter, why do you say that? I have done this in the past with telescope eyepieces when I had a 2 inch eyepiece and a 1.25 inch filter. Outside of the concern for scratching the eyepiece coatings and that need to have my hand holding the filter, it seemed to be effective.

Jon

#10 EdZ

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Posted 20 January 2013 - 12:02 PM

Effective? yes. But it is the least effective position.

Filters are not designed to accept light rays at a large angle. You want the llight rays to pass thru the filter at the least angle possible. That's why telescope filters aare designed to bee placced in front off eyepieeces or diagonals.

edz

#11 Urban Observer

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Posted 20 January 2013 - 12:34 PM

Thank you soo much, Ed :bow:for all your feedback! Excellent stuff! Exactly the kind of opinions we need.
Great idea, re: offering filtered EP's.

-Al

#12 Urban Observer

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Posted 20 January 2013 - 12:52 PM

Not to worry, Jon: The filters of which I speak, are no ordinary nebula filters... :D Just my humble opinion, of course. The filters for this, will be the GCE Nebula Filters, from DGM Optics. I've typed up a short review of them, which I submitted here to CN.
Now, I'm just anxiously waiting for it to be reviewed/approved, and published.
After which, Folks can at least get an opinion on them.

I keep mine screwed on my Garrett SS 10x50's all-the-time, and I love 'em.
Thank you again, to all who responded

#13 faackanders2

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Posted 20 January 2013 - 12:58 PM

Please make a binocular able to screw on 48mm filters in front of the lenses, or larger binos that can screw 1.25" filters on the back of the eyepieces; and or removable eyepieces that can accomodate 1.25" filters in front of the eyepieces (I do this with binoviewers).

P.S. I also have a 48mm filter holder for my 2.3x40 operaglasses which do show improvements on Orion, Lagoon, M27, and North American, and possibly Californian (since Hbeta worked on it naked eye).

#14 faackanders2

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Posted 20 January 2013 - 01:04 PM

or have binos with removable eyepieces that can accomodate the additional length of putting 1.25" filters in front on the eyepiece.

#15 Rich V.

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Posted 20 January 2013 - 03:04 PM

I don't know about the GCE filters but with UHC and OIII the highly reflective, mirror-like coatings on the filters creates reflection problems when mounted on the eye lens side of the eyepieces.

Like EdZ says, with filters outside the eyepiece, the widely diverging light cone leaving the eyepiece isn't as effective as having the same filter mounted ahead of the eyepiece or objective. This is why Al, the OP, wants to mount them behind the eyepiece, I suppose.

Rich

#16 Dan McShane

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Posted 20 January 2013 - 11:06 PM

There is a project, currently in "the works"...
It is: To produce and provide binoculars, with GCE Nebula Filters installed inside the eyepiece barrels.
I'm very excited about this potential new product :) In fact, whenever I use or even think about Binos w/ nebula filters, I get all giddy inside :jump: And, I'd like to see this idea become a reality. "We" are trying to find binoculars that meet the following criteria:

Size: 10x50 or larger preffered
Price range: ~ $200 preferred
Mechanical: Eyepiece optics must be easily accessible. i.e., relatively easy to disassemble/re-assemble the eyepiece barrels.

This last criteria is important. I should also point out, in case anyone is curious: That, yes, EdZ :bow: has been consulted about this already.
What we need now, are some owners of multiple Binos to make some (informed) suggestions...
:question:Which (currently available) binoculars do you think would be perfect for this project?

Below, are just some models that I've been thinking of. Since I don't own any of them, I can't determine if the EP barrels can be disassembled, etc. :confused:

The difficult challenge we face, is to choose one model...out of all the possible prospects :help:

After all, "There can be only one"

Orion UltraView 10x50 Wide-Angle Binoculars
Nikon 12x50 Action EX Extreme ATB Binocular
The Garrett -or- Oberwerk 15x70's might be good?

I will post updates, of any progress that is made.

P.S. I may be wrong, but I don't believe that Pentax Binos are good candidates. Due to their unique eye-cups.

Thanks!
-Al


Here`s images of my cheapo Tasco 10x50s with the internal raw filter setup (GCEs). Despite the appearance in the first image, internal reflections are pretty much nil with this setup.

Dan McShane

Posted Image
Posted Image
Posted Image
Posted Image

#17 Dan McShane

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Posted 20 January 2013 - 11:26 PM

Effective? yes. But it is the least effective position.

Filters are not designed to accept light rays at a large angle. You want the llight rays to pass thru the filter at the least angle possible. That's why telescope filters aare designed to bee placced in front off eyepieeces or diagonals.

edz


Hi Ed,

Actually visual use astro-filters are extremely insensitive to AOI. Even OIII`s still do not present a problem for most amateur visual optical systems, scopes or binos, no matter where they are placed.

The GCE is a notch design and like widebands it is the very insensitive to AOI.

best regards,
Dan

#18 Dan McShane

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Posted 20 January 2013 - 11:34 PM

I don't know about the GCE filters but with UHC and OIII the highly reflective, mirror-like coatings on the filters creates reflection problems when mounted on the eye lens side of the eyepieces.

Like EdZ says, with filters outside the eyepiece, the widely diverging light cone leaving the eyepiece isn't as effective as having the same filter mounted ahead of the eyepiece or objective. This is why Al, the OP, wants to mount them behind the eyepiece, I suppose.

Rich


Hi Rich,

That is one reason the GCE is my favorite for smaller binos. They`re a notch design have a very high optical throughput, a mild and narrow rejection band, and conversely very unoffensive reflections vs narrower filters like UHCs or OIII`s

best regards,
Dan

#19 Dan McShane

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Posted 20 January 2013 - 11:46 PM


It seems the intent is to permanently mount the filters inside, not to be removable by the consumer. that means forever after you are limiting the use of that binocular to nebula observing. Frankly, that might steer some people away from it as too restrictive a use.



That would be my concern. Add to that, the problem of choosing the right nebula filter, O-III, H-Beta, Ultrablock/True UHC?

That would have the added benefit that owners, buying alternate nebula fitted eyepiece sets, could change back to the clear eyepiece set anytime they want.


That seems like an interesting alternative. Along this same line of thinking, how about filters that fit between the observers eye and the eyepiece? With a long eye relief binocular or with individual eyepieces, a set of filter pairs of the different types would allow the filters to be easily changed without disassembling the binoculars. One could even design the external filters to fit the eyepiece cups of popular models of binoculars. One would be out of the filtered binocular market and into the filters for binoculars market.

Jon


Hi Jon,

This is the reason I`m most interested in using my GCE`s for this idea. High optical throughput and TX%. I know even OIII`s can be used with small binos, but my limited experience with small binos so far has been that the GCEs are a good match. I intend to leave the GCEs permanently installed on my prototype 10x50s. (See pics in this thread)

best regards,
Dan

#20 GlennLeDrew

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Posted 21 January 2013 - 12:42 AM

Such filters as high transmission notch filters are certainly viable as a 'permanent' option for city-bound stargazers, if changing out eyepiece sets is considered annoying.

Regarding filter placement. Narrow passband or notch filters are somewhat sensitive to angle of incidence. Behind the eyepiece, for a 60 degree apparent field light can transit the filter at up to 30 degrees off axis. This will 'de-tune' the filter sufficiently so that a considerable portion of the outer field will not be properly filtered.

You can appreciate this simply by peering through the filter while tilting it. For a notch filter, look at a sodium street light and note the tilt which results in an observable brightening of the light. It will be rather less than 30 degrees.

The only type of filter which might deliver full-field performance when placed behind an eyepiece is a broad-band type, such as, e.g., the Lumicon Deep Sky.

#21 Jon Isaacs

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Posted 21 January 2013 - 09:57 AM

Regarding filter placement. Narrow passband or notch filters are somewhat sensitive to angle of incidence. Behind the eyepiece, for a 60 degree apparent field light can transit the filter at up to 30 degrees off axis. This will 'de-tune' the filter sufficiently so that a considerable portion of the outer field will not be properly filtered.



Ed had previously alluded to this, thanks to both of your for explaining this. As they say, one learns something new everyday. I guess I can relax and take a nap, I learned my one things... :)

Do these filters work on the same principle as an Etalon?

Jon

#22 Dan McShane

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Posted 21 January 2013 - 11:31 AM

Regarding filter placement. Narrow passband or notch filters are somewhat sensitive to angle of incidence. Behind the eyepiece, for a 60 degree apparent field light can transit the filter at up to 30 degrees off axis. This will 'de-tune' the filter sufficiently so that a considerable portion of the outer field will not be properly filtered.



Ed had previously alluded to this, thanks to both of your for explaining this. As they say, one learns something new everyday. I guess I can relax and take a nap, I learned my one things... :)

Do these filters work on the same principle as an Etalon?

Jon


An Etalon would be an example of filter which is extremely sensitive to AOI change. For the most part this is due to the "spacer" layer. With most common interference filters the spacer is a relatively thin optical layer deposited between sets of layers, both before and after the spacer, which are referred to as the reflectors. Generally speaking the thickness of the spacer determines bandwidth of the resulting filter. With an Etalon the optical spacer is replaced with a very thin physical spacer placed between the reflectors. And, although it`s still quite thin, it is much thicker than a traditionally constructed interference filter spacer, but even more important, it is also much more consistent in terms of refractive index than an optically deposited spacer, which would require many more 1/4 waves of optical deposition than is practical, to equal the same thickness, and thereby produce the desired narrow bandwidth.

#23 Urban Observer

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Posted 21 January 2013 - 03:14 PM

Here`s images of my cheapo Tasco 10x50s with the internal raw filter setup (GCEs). Despite the appearance in the first image, internal reflections are pretty much nil with this setup.

Dan McShane

Posted Image
Posted Image
Posted Image
Posted Image [/quote]

...Almost makes me want to buy a pair of Tasco's :grin: Almost

#24 Dan McShane

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Posted 22 January 2013 - 08:45 AM

Such filters as high transmission notch filters are certainly viable as a 'permanent' option for city-bound stargazers, if changing out eyepiece sets is considered annoying.

Regarding filter placement. Narrow passband or notch filters are somewhat sensitive to angle of incidence. Behind the eyepiece, for a 60 degree apparent field light can transit the filter at up to 30 degrees off axis. This will 'de-tune' the filter sufficiently so that a considerable portion of the outer field will not be properly filtered.

You can appreciate this simply by peering through the filter while tilting it. For a notch filter, look at a sodium street light and note the tilt which results in an observable brightening of the light. It will be rather less than 30 degrees.

The only type of filter which might deliver full-field performance when placed behind an eyepiece is a broad-band type, such as, e.g., the Lumicon Deep Sky.


Hi Glenn,

The GCE is even less sensitive to AOI than a Deep Sky. But neither filter is a problem for any optical system slower than around f/4. If you plot the rays for an f/4 system the worst case deviance of rays from 0 AOI will be about 7.5 degrees. That will only shift the filter CWL about 1-2 nm, which is within the +/- manufacturing tolerances of most visual astro-filters anyway.

best regards,
Dan McShane

#25 Dan McShane

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Posted 22 January 2013 - 09:03 AM

[quote name="Urban Observer"]Here`s images of my cheapo Tasco 10x50s with the internal raw filter setup (GCEs). Despite the appearance in the first image, internal reflections are pretty much nil with this setup.

Dan McShane

Posted Image
Posted Image
Posted Image
Posted Image [/quote]

...Almost makes me want to buy a pair of Tasco's :grin: Almost [/quote]

LOL!!! the real treasure in the pics is my circa 1967 JHS woodshop chessboard .... I have a long time friend and fellow chess player who tries to buy it from me every time we meet ... he`s been doing it since we first met in 1974 ... the answer has of course been; no ... :lol:






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