Kutter binoculars 120/f31

[Chriske]

Busy installing these 36 ball bearings.
I should not have use these LMUU in the first place, I only wanted to use them because it is far less work to install them.
Anyway, these 'selfmade' bearings are far better, especially because I can completely rule out all play in that system.

[Chriske]

While assembling the scopes, drawing the fork and mount. I'll be using OnStep software.
Between these two (blue)forks the(altitude)stepper, together with worm and wormwheel, will be installed.

[Chriske]

SaturnV project is finished, now I can continue working on this one.

Today I made a first attempt to make a sturdy tripod for that bino. Well imo this is a sturdy one, and heavy too..😁
There will be two platforms. The first one, the highest branch,  is for the bino itself. That smaller branch(mid-right) is for a smaller platform holding eyepieces and stuff.
Both still need to be cut to the correct height.
It's wood btw from an apple-tree. It's old, full of moss, very irregularly shaped, I love it.

The bottom is a sandwich of 3 layers 18mm plywood. These will be painted green, about the same colour as the branches itself.
All is bolted together with thick hex-head wood-screws.

[Gina]

It's certainly different!  I wonder if it will be rigid enough.

[Chriske]

I have no problem at all you calling that 'thing' ugly Gina...
Rigid..? Well the thickest branch is about 12 cm diameter. These three thick branches set in a triangular formation, no doubt about that.

In fact my point is (first of all it saves me lots of time making this tripod) I wanted to make a combination of that very rough looking tripod combined with a piece of high tech-telescope on top of that rough piece of wood. It's that contrast I like very much.
On thing is certain, it'll be an eye-catcher during open door mid September. And I'm pretty sure many people will repeat these words you just posted here : It's certainly different!
Each time someone says that during OD, I will smile and think of your words.

[Gina]

I didn't say it was ugly, in fact it's rather nice.

Edited July 10, 2019 by Gina

[Chriske]

31 minutes ago, Gina said:

I didn't say it was ugly, in fact it's rather nice.

Nice..! Thank you...!

[Chriske]

Raining outside so back to drawing...

adding Nema11 stepper(built in 1:100 reduction) + worm/wormwheel to altitude axis.
Need two of these :

 

[Chriske]

Removed one post to have free view on the Alt-drive.
Altitude bearings running on 8 ball bearings.

[Gina]

I guess a gearbox stepper motor is alright as long as there isn't too much backlash.  My DIY fork mount for widefield imaging will have timing belts for the drive.

Edited July 12, 2019 by Gina

[Chriske]

I did use these steppers in another astro-project Gina, they're incredibly good.

[Chriske]

Change of concept.
Worm on top of the wormwheel. The worm is springloaded pushing the telescope very gently in its fork.

Telescope in action

 

To hang it in or remove the telescope out of it's fork I rotate the worm away

[Chriske]

Both IPD units with that renewed linear ball bearing system installed. There's no play at all and the action is very smooth. This is far better compared to the earlier system with these LMUU8 linear bearings. I'm very happy with it.

Inside the big holes of these IPD-units there are hex-holes around the perimeter. In these hex-holes I insert nuts and with set-screws I'll be able to adjust the direction of the focusing-tubes. Both these tubes should be absolutely parallel.

I'll be able to adjust IPD from 55mm to 72mm. So only very little children are not 'covered'. Pity I know, but that's the price I have to pay, otherwise I would not have been able to use 2" eyepieces in that bino.

[Chriske]

Altitude worm-wormwheel unit .
On the right there's that hole. I was planning put a piece of metal/brass and a bolt in it. That bolt would prevent the worm from axial movement during action. But there's no need at all because there's no axial play at all in that stepper's gearbox(hidden in that printed part).
The upper-centre hole is the rotating point to release the worm from it's wormwheel during assembling and back.

Stepper Gear box 1:100
Worm/wheel  : 1:42

[Ben the Ignorant]

It's the first time I notice this thread, now following it with interest. That's one big commitment.

[Chriske]

Not an easy task, let that be clear.
But I like a challenge, especially building telescopes.

[Peter Drew]

As another builder of unusual telescopes I've been following this thread with interest. There seems, from the CAD sketches, that there is a considerable amount of off axis weight above the pivot point in declination. How are you proposing to address this?.    😀

[Chriske]

Peter,

The balance of that bino is the very last thing I'll be dealing with.
Decades ago I've built several larger Kutter-telescopes. Not one of these Kutter was built using the same materials. So back then I never knew in advance where the COG would be. But because of my experience with these scopes I have a good estimate.
Compared to these old Kutters I've built in the past, I have now kind of a lead. Inventor tells me were the COG is, But that also is an estimate because Inventor thinks the complete scope is made using the same materials.

Above that pivotpoint is a lot of material indeed. Most of it is PVC and PLA and one mirror. But below that same point is the SS secondary tube. That'll compensate for the mass above.
I will only know about that COG when the scope is completely assembled, even eyepieces and two powerpacks will be taken into account.
That is the moment where I need to add some weight(s) somewhere 'around' that scope. I'm also planning to hide as much as possible of these weights, (out of sight).

This is were the COG Inventor thinks it is now, so for the moment it is 94x82 mm wrong. But for the moment that COG is changing constantly, just a litlle bit, because I regularly add a part in that assembly, and sometimes I remove one. So for now I don't bother at all were Inventor tries to tell me were the COG is.

 

[Chriske]

Printing the fork's. It takes almost 24 hours to print one. I even needed to cut them in two because my bed is not large enough.
The square slots in the forks are for M6 nuts.

Purpose of these nuts and threaded rods is to keep both parts together but most of all to keep the forks firmly to its platform.
When all is done , I'm planning to close the slots so there's no trace of these nuts and rods.

 

[Chriske]

First fork completely printed and assembled. 4 ball-bearings for each fork.
Going to add a very thin strip of brass around the alt-bearing, 40mm wide. That’ll be necessary I think, otherwise the ball-bearings will dig itself in the PLA when the scope is stationary for a long time at the same spot. I have no idea of the weight of the complete scope this moment. Better save than sorrow...
On the other hand I think nothing will happen because the scope is supported by 8 ball-bearings.

[Chriske]

Both drives done now :

[Gina]

Very nice

[Chriske]

Both focusers just finished assembling, tested and they do work magnificently well. I'm very pleased with them.
I can also use 2" eyepieces, but not these very large diameters eyepieces.

[Chriske]

Painting the secondary tube's baffles.
Easy job because I didn’t had to rotate the cylinders while spraying the paint. Due to the pressure of the aerosol container the baffles ran by themselves, so I only had to follow the baffles.

[Chriske]

And these are extra flat baffles that will be installed between the baffles shown in the picture here above.
Holes in these baffles is 50mm.
The inner diameter of that first flat baffle (seen from the secondary mirror) should be correct. If the diameter is to small it will act as an obstruction to the incoming light, ending up with darker images. If that diameter is chosen to large, direct light from the Moon will enter at a shallow angle into the secondary tube. It needs to be perfect. When it is, these scope deliver high contrast images.