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Equipment Discussions >> Binoviewers

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denis0007dl
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BinoVue Clear Aperture prism? new
      #5641183 - 01/24/13 06:12 PM

Could some of BinoVue owners measure precisely Clear Aperture prism on telescope side?

I know info that BinoVue have 27mm aperture prisms, but what is his really Clear Aperture prism on telescope side?

Thanxs for mesurements!


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GlennLeDrew
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Re: BinoVue Clear Aperture prism? new [Re: denis0007dl]
      #5642292 - 01/25/13 10:32 AM

The front aperture is more a limiter on the fastest f/ratio which can be accommodated. As long as it's large enough to accept the on-axis light cone, all is well. For longer f/ratio telescopes, this aperture can be surprisingly small.

For example, let's for the moment assume the equivalent air block of the optical path length through the BV's glass, and the additional rearward location of the focus behind the rear prism aperture together to be, oh, 80mm. For an f/10 scope, its on-axis light cone would be just fully accommodated by a front BV aperture of only 8mm. A little extra aperture is useful for fully accepting the off-axis light cones, but it doesn't require very much extra to do this.

If you plan to mate the BV to something like an f/5-ish system, then the front aperture, in conjunction with the optical path length/focus location with respect to the rear prism aperture, becomes critical.


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denis0007dl
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Re: BinoVue Clear Aperture prism? new [Re: GlennLeDrew]
      #5642352 - 01/25/13 11:12 AM

Quote:

The front aperture is more a limiter on the fastest f/ratio which can be accommodated. As long as it's large enough to accept the on-axis light cone, all is well. For longer f/ratio telescopes, this aperture can be surprisingly small.

For example, let's for the moment assume the equivalent air block of the optical path length through the BV's glass, and the additional rearward location of the focus behind the rear prism aperture together to be, oh, 80mm. For an f/10 scope, its on-axis light cone would be just fully accommodated by a front BV aperture of only 8mm. A little extra aperture is useful for fully accepting the off-axis light cones, but it doesn't require very much extra to do this.

If you plan to mate the BV to something like an f/5-ish system, then the front aperture, in conjunction with the optical path length/focus location with respect to the rear prism aperture, becomes critical.




Thanxs, but I still need measuements of clear aperture prism on scope side!


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denis0007dl
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Re: BinoVue Clear Aperture prism? [Re: denis0007dl]
      #5642744 - 01/25/13 02:53 PM

Does anyone have TeleVue BinoVue to measure that?

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GlennLeDrew
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Re: BinoVue Clear Aperture prism? new [Re: denis0007dl]
      #5644336 - 01/26/13 12:46 PM

In the absence of real data, you might provisionally assume 21-22mm as likely. I'm curious to know if you have a minimum aperture below which you prefer not to have. What scope(s) do you intend to binoview with?

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Fred1
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Re: BinoVue Clear Aperture prism? new [Re: GlennLeDrew]
      #5644386 - 01/26/13 01:15 PM

With the 1.25" nose piece removed, I measured the interior diameter of the Bino Vue's aperture at 30.09 mm with my digital caliper. Is that what you needed?

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denis0007dl
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Re: BinoVue Clear Aperture prism? new [Re: Fred1]
      #5644446 - 01/26/13 01:55 PM

I need Clear aperture diameter prism on telescope side, measured like on the picture, just for info..



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GlennLeDrew
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Re: BinoVue Clear Aperture prism? new [Re: denis0007dl]
      #5644508 - 01/26/13 02:32 PM

If 30mm, that's surprisingly large for a 1.25" format, it being larger than a 1.25" barrel's ID. What's needed is the diameter of the nosepiece's inside diameter where it abuts the beamsplitter.

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Fred1
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Re: BinoVue Clear Aperture prism? new [Re: denis0007dl]
      #5644515 - 01/26/13 02:35 PM Attachment (24 downloads)

I measured from the hard surfaces between the two arrows.

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Fred1
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Re: BinoVue Clear Aperture prism? new [Re: Fred1]
      #5644540 - 01/26/13 02:47 PM

Well, I did my best. My apologies but I no longer have the nosepiece, at least it's not handy. I suggest that the OP call TV for the info. I realize it's an international call but it might be worth it to get the exact info. FWIW, as I recall from when I had an Orion Filter Wheel, the 1.25" nose piece for that was the same nosepiece as on the Bino Vue. Both were T-Threaded. (I now use my Bino Vue with a PTR-2200 T adapter with a Powermate 2x for my Dob. Thus, the missing nosepiece.) Good luck with your endeavor.

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denis0007dl
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Re: BinoVue Clear Aperture prism? new [Re: Fred1]
      #5644549 - 01/26/13 02:52 PM

Thanxs for measurements, but 30mm aperture prism is not possible, because BinoVue have 27mm prisms as you can see

BinoVue Home Page

30mm of hole ddiameter is possible...


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Fred1
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Re: BinoVue Clear Aperture prism? new [Re: denis0007dl]
      #5644596 - 01/26/13 03:23 PM Attachment (18 downloads)

I have a Siebert Power Mag Wheel which is an Orion Filter Wheel with barlow lenses in it. As I mentioned earlier it uses the same nose piece as the TV Bino Vue. The inside diameter of the nosepiece meausred 28.07mm. I can't locate the original TV nosepiece. I hope this helps.

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Fred1
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Re: BinoVue Clear Aperture prism? new [Re: Fred1]
      #5644928 - 01/26/13 07:08 PM Attachment (20 downloads)

I found the original TV BV nose piece. It appears the TV is manufactured to different specs than the Orion. I measured 28.42mm at both the front and back of the nosepiece. I hope this helps.

This pic is the part that goes "butt up" against the BV's opening just in front of the prism.


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Fred1
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Re: BinoVue Clear Aperture prism? new [Re: Fred1]
      #5644934 - 01/26/13 07:11 PM Attachment (22 downloads)

This pic is the measurement that faces into the telescope.

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GlennLeDrew
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Re: BinoVue Clear Aperture prism? new [Re: Fred1]
      #5645081 - 01/26/13 08:30 PM

Thanks for all those measurements and pics, Fred! So it would seem the Binoview has a rather generous clear aperture at the front end. How about the apertures at the back end?

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Fred1
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Re: BinoVue Clear Aperture prism? new [Re: GlennLeDrew]
      #5645144 - 01/26/13 09:13 PM

Not sure how I can help you there, Glenn, if you're looking for a measurement inside the bino at the EP end. It snugly takes 1.25" EPs and handles my 24mm Pans' 27mm field stops with no vignetting. Heck!! I still don't understand why the OP needed the measurements to begin with.

Edited by Fred1 (01/26/13 09:17 PM)


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