DIY 16" binoscope

[keith5700]

Hi all. First post so go easy on me.

I'm building a 16" binoscope. I've been at it since Xmas and thought I'd put some pics up of progress so far.

I'm sure most of it's construction is self explanitory from the pics, but a couple of things are maybe worth a note.

The main focussing is done by raising and lowering the main mirrors, which are fixed to a frame which slides on hardened shafts and linear bearings. The focussing knob is at the top and this drives a screwed shaft through the centre of the main tube.

The eyepiece width is achieved by sliding the eyepiece holders apart and together, again on shafts and bearings.

The diaoptre adjustment is done by moving the eyepieces left or right as a fixed pair.

So, the first adjustment is to set the eyepiece width. Then, whilst looking at a star, the pair is moved left or right to get both stars equally out of focus, which is easy as the images are concentric.

Then the main mirrors are adjusted to bring it all into focus.

Sounds complicated but it only takes a few seconds, after a bit of training.

There is a control box for the eyepiece adjustment so they are moved by turning some knobs, and 3 settings, for 3 viewers, can be stored and retrieved from the controller.

Anyway, I'll see if I can get some pics to load.

Keith.

[Psychobilly]

Awesome :icon_salut:

[lukebl]

Awesome :icon_salut:

You took the words right out of my mouth!

Doubly awesome.

[beamish]

And again ! Superb, well done !

[Earl]

Like WOW!!!

how does it perform?

I read up on the massive bino scope in the US and it gives a huge mirror.

Is this the way forward?

Dobsonian Binoscopes?

Edited May 19, 2010 by Earl

[sgazer]

wow, I've never seen anything like it. You must have gone to immense effort to create that. Are you a machinist, did you make all the parts yourself? I'm amazed!

[Doc]

Stunning it must have took a lot of hard work, can you tell me about those Alt/Az guages and it's set up.

[brantuk]

You just gotta bring that down to EMS dark site - early and in the daylight before sunset.

[Euan]

What an amazing piece of engineering

Is there an award for the best first post ever?

[mdstuart]

Or perhaps picture of the week!

[LeoLion]

Mmmmm . Telescope making is still alive and well in the UK . The Bolton AS ATM ers have done a smaller one. Did you do an earlier 12" bino too ? It may require a shroud like Dracula's cloak to keep the stray light out !! Bridgeport Miller in the shed ?

Yummy scope ,

Len E

[acey]

Awesome!

Like those secondary mounts. What sort of diffraction do you get from the vanes?

[Coco]

This is possibly the 'MOST' exciting project I've seen on any astro forum..

Respect!

Guy..

[DarkerSky]

WOW !!! That is outrageously stunning !! Really quite bowled over by that. Fantastic stuff !!

[Brett]

WOW:eek:

[step_hen]

Jaw dropping!

[themos]

That's a bit too flash for my liking....joke!

[LukeSkywatcher]

16" bins !!!!

I am drooling.

[argonaut]

A stunning project. I really hope to see more of your posts on this project.

It's looking and sounding very good so far

Please keep us all informed.

Glen.

[keith5700]

Well thanks for the replies.

Afew quick questions answered first.

Yes I am a design engineer and have a full workshop for hobbies, including the Bridgeport.

Yes I did make a 12" version of this a long time ago.

No I've not noticed any funny diffraction spikes from the 2 arms but will try and take more notice next time out.

The alt-az gauges are about £50 each and they're just a general engineering type of angle display.

The Az encoder is belt driven off the main axle and there's a clutch under the knob so the encoder can be turned without moving the scope. So I set the scope to a known object, find the angles off the laptop, and then turn the encoders to read that angle. They work fine, but switch themselves off after 10 mins of not moving, and reset to zero, which is a pain.

[keith5700]

One thing I've not seen on other binoscopes is the coning angle I've put on the eyepeice holders. The eyepieces have an included angle of 4 degrees.

When I did the last 12" bino I used to get eyestrain fairly quickly and eventually guessed it could be from looking down 2 parallel eyepieces but trying to form an image, say, a metre in front of me. I think it was confusing my brain!

So I angled the eyepieces in on that scope and it cured the problem. It was really comfortable and natural to look through after the mod.

So I did it on this one from the off.

The worst bit was getting everything aligned. As the main mirrors track up and down the centre tube then the mirror sets had to be not only aligned with each other, but parallel in both planes to the centreline of the main tube.

We had water tube levels, plumb bobs and all sorts of lasers filling the workshop on that day!

I've set the left hand side as the datum and any little tweaks to get a nice comfortable image are done on the right hand secondary mirror.

This only needs doing sometimes after changing eyepieces.

Thanks for all the comments.

Keith.

[LukeSkywatcher]

It sure is an impressive looking bit of gear and i salute your workmanship.

Would it be rude to ask about costings for the build?

finished item,i mean.

[keith5700]

Sorry I'm doing multiple posts but I typed a long reply and lost the lot an hour ago.

The other thing on the scope is the centre mast raises and lowers. This is so whatever altitude the scope is at, it can be raised or lowered so the viewer can remain standing.

Provided you wait for the mast to move. It needs a bigger motor on it really as it takes a couple of mins to go from full down to full up, about 600mm.

This isn't the ultimate design for a binoscope, far from it. I ran out of money with the mirrors so the scope is made mainly from bits and bobs lying around the workshop.

I'm sure it could be simplyfied/improved by purchasing better sizes of tube etc.

[FraserClarke]

Very nice!

Do you observe from a dark site, or so you find any problems with scattered light? I see you have the baffles behind the secondary mirrors, but are there any others??

I would have thought one of the problems is co-aligning the two mirrors so that the field of view is reasonably common between the eyes? I guess the brain is more tolerant of a mis-alignment than a camera, but how good does it need to be?? I guess you have collimation screws on the primaries?

What resolution are the alt/az encoders?

Sorry for lots of questions -- just interested

[keith5700]

It sure is an impressive looking bit of gear and i salute your workmanship.

Would it be rude to ask about costings for the build?

finished item,i mean.

No, not rude at all.

The 6 mirrors were about £3600. These were bought by a friend of mine who has financed most of the build, and kept me on a practical level when my imagination starts to run wild with things i could incorporate into the design.

I've spent about £500 on the mechanics and electrics so far.

Most of the cost to reproduce one of these would obviously be in the labour. Not sure how many hundreds of hours have gone into this so far, and there's no drive systems or goto on it yet.

I've seen a 16" bino from JMI? in the USA which they sell for $16,000.

To finish this properly with an encoder type goto drive system, and light shrouds etc will need another £3-4000. So I'm guessing it won't ever be finished!