7 replies to this topic

[bykhed]

I have a Parks binoviewer I picked up in the classifieds here on CN, which I think is a converted microscope head. It is very similar to the older Celestron BVs with the 60 degree angle and the sliding IPD adjustment (see attached photo of Celestron BV).

It works great in my CATs and I am just buying a 127ED triplet f/7.5 refractor. Will this BV work in the refractor without a barlow? I won't have a diagonal in-between the BV and focuser.

Thanks!

-Matt

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[Tak North]

Only one way to find out - give it a try. Unless you happen to know the internal optical path of the BV and the amount of backfocus available for the new scope.

One thing to keep in mind is that those microscope heads have a very small clear aperture. It probably works OK with your CATs because of the high focal ratio, but a fast APO will have a much wider light cone and you will be losing allot of light due to vignetting.

[bykhed]

Thanks for the info. I haven't measured the clear aperture but I know that I can use Celestron 26mm plossl eyepieces without vignetting in my CATs.

-Matt

[johnnyha]

Should work!

[Erik Bakker]

Congrats on a great bino made in Germany. It is a Baader: very sharp, with minor ghosting. It will work wonderfully in your 120mm refractor. The focus position is roughly the same as that of a 2" diagonal with a 1 1/4"eyepiece in mono mode. Take that out of the focusser, insert the 60 degree bino and voila, your bino image will be sharp with minor focustweeking. You may want to look for a pair of 19mm PanOptics or Celestron Axioms (Japan). They give the widest true field of view at a great magnification. And when you enter a 2x A-P barcon barlow, you will have a great magnification for the moon and planets. Great convenience a la Questar.

CS,

Erik

[bykhed]

Thanks, Erik. I should clarify that the photo is not my binoviewer but mine looks VERY similar. It's marked "Parks - Japan". I'll post a photo of it here.

-Matt

[bykhed]

Good news - I got it to work with my Stellarvue 70ED Raptor refractor! I had to rack the focuser out quite a ways but it didn't seem to vignette with 19mm Axioms (old type).

Tonight will try it out with my new (to me) Meade 5000 triplet 127mm.

-Matt

[Erik Bakker]

Hi Matt,

Congrats on the good news, glad that the bino works in your scope. On the old type 19mm Axioms (I presume the made in Japan 1 1/4" Celestron Axioms): they are one of the finest eyepieces for binoviewing I have ever used. You may want to use a good 2" 2x barlow in front of the bino to increase the magnification by 2.5-3.5 times due to the glaspath of the bino. In that way, you have the maximum widefield views possible with 1 1/4" eyepieces in your bino AND a great magnification for the moon, planets and doubles. As a bonus, the "Einblick verhalten" of thge 19mm is tuned to perfection by the barlow. It does require more focussing outwards, so you may need an extension tube to reach focus.

Enjoy your new window on the heavens and clear skies,

Erik