Double Doublers (1 Viewer)

danhdz · Sep 8, 2004

Hi folks,

I have an 8.5 EL, the doubler, and the tripod adaptor thing. It makes a good, light, little scope. I had the idea last night of getting another doubler so that now I would have a pair of high-powered bins too. I looked at the instruction manual for the doubler and there is a diagram showing this set up (2 doublers) with an "X" through it. Presumably this means that this should not be done. I, however, don't see why not; the doubler screws into both eyepieces equally well, the threads look pretty sturdy and since the focus is internal (in the bin) there are no moving parts to get strained.

So, has anyone tried this setup? And/or does anyone see any reason why this would be ill-advised or wouldn't work?

Many Thanks,

Dan

henry link · Sep 8, 2004

danhdz said:
Hi folks,

I have an 8.5 EL, the doubler, and the tripod adaptor thing. It makes a good, light, little scope. I had the idea last night of getting another doubler so that now I would have a pair of high-powered bins too. I looked at the instruction manual for the doubler and there is a diagram showing this set up (2 doublers) with an "X" through it. Presumably this means that this should not be done. I, however, don't see why not; the doubler screws into both eyepieces equally well, the threads look pretty sturdy and since the focus is internal (in the bin) there are no moving parts to get strained.

So, has anyone tried this setup? And/or does anyone see any reason why this would be ill-advised or wouldn't work?

Many Thanks,

Dan

For fun I tried a thing like this by simply placing a pair of 2.3X Russian opera glasses behind the eyepieces of my EL's and some other bins. It did work, producing a very narrow field (10 degrees AFOV) but well enough collimated image of about 20X in the EL. Collimation will probably be a problem with two Swaro doublers, however, since they will not be collimated relative to each other as my opera glass barrels are. The apparent field will also be narrow as you can see from the doubler you already have, and there is the time and trouble involved to install and remove the things in the field.

I think the Zeiss 3X12 opera glass is about the same thing optically as two of their 3X boosters put together. Might be interesting to try that.

hinnark · Sep 10, 2004

danhdz said:
Hi folks,

I have an 8.5 EL, the doubler, and the tripod adaptor thing. It makes a good, light, little scope. I had the idea last night of getting another doubler so that now I would have a pair of high-powered bins too. I looked at the instruction manual for the doubler and there is a diagram showing this set up (2 doublers) with an "X" through it. Presumably this means that this should not be done. I, however, don't see why not; the doubler screws into both eyepieces equally well, the threads look pretty sturdy and since the focus is internal (in the bin) there are no moving parts to get strained.

So, has anyone tried this setup? And/or does anyone see any reason why this would be ill-advised or wouldn't work?

Many Thanks,

Dan

Hi Dan,

I had the same idea as you and so I asked Swarovski and Zeiss about it on a birding fair. Both said clear that it doesn´t work and they wouldn´t recommend it. The problem is to get a coherent image when watching with both eyes caused by collimation problems and by a too narrow field of view. So I didn´t try this any further.

Steve

Double Doublers (1 Viewer)

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henry link

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