Small angled GOTO bins?

[PeterW]

Noticed i’d got a few spare 9x50 finders and knowing the benefit of angled binoculars for ease of viewing near the zenith I wondered if I could make my own. Currently no IPD adjust and better focus/collimation is still to be added, but initial trials are promising, focus being a little sensitive these being f3.2 objectives.

With the eyepieces I have I can switch between 7x/10x/12x50, using >65degree eyepieces. Given the lack of field flattener and fast objectives the edges are not going to win any prizes, but the sweet spot is quite useable and the stable view makes seeing faint stars much easier.

I included a synta rail in the design, so now I have 90degree GoTo binoculars when mounted on an AZ-Gti… almost cheating.

 

Peter 

[Ships and Stars]

This is brilliant. I bet the NAN and Milky Way would look incredible with these. I really like the concept. Wonder why more binoculars with interchangeable 1.25 eyepieces aren't out there, besides giant bins. Might be onto something here!

[Kimboman]

great idea binoculars viewing is the way forward I am certainly hooked ,I use my binoculars viewer at every opportunity.

I have never observed the moon and planets in a single eyepiece that can compare with binoculars viewing

[PeterW]

Certainly a gap in the market, but then you’d be paying extra for flexibility rather than anything necessarily optically better. Imagine a pair of 70mm APM with even smaller objectives!! Also the current large binoculars have longer focal ratios  to give good views, but this then impacts on the maximum exit pupil that they can deliver (24mm max focal length for 1.25” eyepieces), people are showing large exit pupils are capable of showing a lot of really quite impressively faint stuff. Of course fast optics are hard to correct and deliver sharp fields for. Everyone knows small binoculars are handheld, but we know that the more stable the views are the better.

 

I hope that these make for good large scale sweeping binoculars, I’m thinking of adding swappable filters to make nebula hunting easier. Under my skies galactic nebulae are way beyond the reach of conventional glass 😉

Version1 is designed for my IPD and the miscollimation can usually be sorted by some  wiggling. I plan several more iterations in the coming months to end up with something that others could equally well use and enjoy.

I’d be interested in understanding what lenses I might need to add some field flattening, though they may just end up as another source of miscollimation or vignetting, can but try.

I need to find a company to cost effectively add some anti-reflection coating to the prisms to up the transmission.

 

Hopefully the new year might bring options to get to darker skies to see what these CaK deliver.

 

Peter

[Paz]

I've been on the odd camping holiday where my whole set up was just a hand held 9x50 finder due to lack of space.

I wondered back then about making a pair into right angled bins but laziness and a lack of the necessary skills/brains got in the way.

[Peter Drew]

I have a similar setup.  I made the binocular a couple of years ago following a post on CN asking why was there no small angled binoculars.  I had enough bits to build one so thought why not?.  I was amazed how good they were considering they were pretty cheap binocular objectives.  Unfortunately using high grade components soon racks up a considerable outlay.  I've often been tempted to use a pair of the 50mm SWED guide scopes, but again, the cost!     🙂

[WJC]

You can make your EPs out of two Plossels from any two identical (cheap) binoculars. Plossel is just the more expensive name for symmetrical doublets.

[PeterW]

I am only attempting this as I have been 3D printing stuff for a while and so happy to design, test and combine different design aspects as I move towards a final version. The printer doesn’t care how complex things are, though you need to be careful to ensure it prints well and any supports can be properly cleaned off.

If I had had to buy the finders, eyepieces etc it wouldn’t be worth it. 2”‘erecting diagonals probably house bigger prisms, but they aren’t common or cheap. 

Effortless, rock steady views of the zenith with no arm strain, I could get used to this…..

If/when I have a more user friendly version I’ll post to e OpenSCAD code so anyone can tweak it to the parts they own, it’s rather Kludgey at the moment……

 

Peter