DIY 16" binoscope

[keith5700]

40 minutes ago, AstroKeith said:

Nice engineering!

The price you get is proportional to the size of the market. This is a pretty unique instrument and you may be searching for a customer, rather than the other way around. Anyone interested in forking out say £6k is going to be pretty demanding too. (If it was me I'd worry about dew)

So I definitely consider selling just the mirror sets.

Yes, I fear you may be correct.

[PeterW]

C11, assume you’ve seen this post https://www.cloudynights.com/topic/503466-celestron-c11-binoscope-with-matsumoto-ems/# worth asking how it went and for tips. Good luck. Maybe a faster, slightly smaller bino, more postable and wider fields?

 

Peter

[keith5700]

8 hours ago, PeterW said:

C11, assume you’ve seen this post https://www.cloudynights.com/topic/503466-celestron-c11-binoscope-with-matsumoto-ems/# worth asking how it went and for tips. Good luck. Maybe a faster, slightly smaller bino, more postable and wider fields?

 

Peter

No I hadn’t. Thanks, it was very interesting.

[PeterW]

Maybe a look at Mel Bartels thoughts on Richfield, entendres and binocular summation… https://www.bbastrodesigns.com/tm.html#myProjects the things he’s seen with very fast 7mm exit pupil are awesome, but 2eyes would mean more better….

 

peter

[Peter Drew]

I have built both SCT and Maksutov binoscopes, initially attracted by the compactness.  However, the relatively high resultant magnification and restricted field of view, for me, detracted from the main benefit of binoviewers, the wide field potential.  In this regard I feel that refractors and Newtonians are a better option.

Another drawback of the catadioptric binoviewer is that considerable back focus is necessary to account for the additional optics to achieve translation to normal eye separation, although possible easily due to the moving mirror focusing, any mirror shift causes misalignment of the images.  Adding a third party external focuser to overcome this just exacerbates the back focus problem.    🙂

[keith5700]

51 minutes ago, Peter Drew said:

I have built both SCT and Maksutov binoscopes, initially attracted by the compactness.  However, the relatively high resultant magnification and restricted field of view, for me, detracted from the main benefit of binoviewers, the wide field potential.  In this regard I feel that refractors and Newtonians are a better option.

Another drawback of the catadioptric binoviewer is that considerable back focus is necessary to account for the additional optics to achieve translation to normal eye separation, although possible easily due to the moving mirror focusing, any mirror shift causes misalignment of the images.  Adding a third party external focuser to overcome this just exacerbates the back focus problem.    🙂

Yes, all valid points. There’s no getting around the field of view reduction, so I’ll have to think if I can live with it.

I’ve not done much work on a design yet, but I was thinking of spacing the tubes apart and bringing the light cone out the side of the tube.

[Peter Drew]

6 hours ago, keith5700 said:

Yes, all valid points. There’s no getting around the field of view reduction, so I’ll have to think if I can live with it.

I’ve not done much work on a design yet, but I was thinking of spacing the tubes apart and bringing the light cone out the side of the tube.

That would be an interesting option, I presume you propose tertiary flats?  Catadioptric telescopes usually have large central obstructions so plenty of room to hide them.   🙂

[keith5700]

On 04/07/2023 at 20:09, Peter Drew said:

That would be an interesting option, I presume you propose tertiary flats?  Catadioptric telescopes usually have large central obstructions so plenty of room to hide them.   🙂

Yes, tertiary flats, similar set up as on my current scope. Hoping it will be a bit easier as I won’t be standing in the light path.

[keith5700]

Well, it’s up for sale on the Astrobuysell site. I’ve put it up for £4750. No takers yet, but been offered a couple of interesting swaps.

Itching to get started on the next one.