12" Binocular Telescope - now building my set

[omaroo]

Our astro society (Macarthur Astronomical Society) had Mark Suchting of Deep Sky Optics as its guest speaker tonight. He gave a great talk on the theory and practice of binocular telescope design and use - which he has been practising for 20-odd years, and even had John Dobson ask him to build him a set at one stage).

As a real bonus he also brought along Paul Shoppis' set of 12" binos that I originally fell in love with at the Lostock star party this year and again at South Pacific Star Party. Thanks Mark for driving all the way south to Macarthur to show people what a great viewing experience can be had through a set. Images of this unit are here on my site: http://www.omaroo.com/index.php?option=com_g2bridge&view=gallery&Itemid=2&g2_itemId=2211

Anyway - as an added surprise he brought my two new perfectly matched f/5's that he had been working on for eight months and had just completed!! They are true sparklers, and I can't wait to start to build the binos now that the core components are here and ready to go

I'll keep this thread going as I go through each process. Keep coming back for more as I progress. Can't wait to start designing the hardware now - materials, mirror cells, electro-mechanical collimation systems, rotating cages, etc, etc, etc.......

I guess that there is a fair whack of theory to be applied first to come up with the appropriate dimensions of everything. Based on these I'll make a decision on what materials I'll use - nice wooden components or lots of aluminium & carbon fibre. I'll start to order accessories such as 3-vane curved spiders, focusers, truss joints, etc, etc now.

The journey begins!

Here are our two new babies:

http://www.omaroo.net/albums/album46/DSC_2646.sized.jpg

Mark Suchting and his optics in Paul Shoppis' 12" binos at Lostock this year:

http://www.omaroo.net/albums/album43/Lostock_021.sized.jpg

http://www.omaroo.net/albums/album43/Lostock_017.sized.jpg

Cheers
Chris

[Caveman]

I'm Impressed:welldone:

[Radar]

I'm well impressed mate. Great DIY project. How long do you reckon it will take to build?

Ray

[omaroo]

Thanks Michael & Ray :)

Ray - I'm not going to rush it. I have the optics now which gives me room to move. I plan to use an open-box design to do away with the rocker box altogether - too much unnecessary weight given the two mirrors.

I'm looking at emulating the Obsession Ultra Compact design and attaching the truss tubes directly to the alt bearings:

http://www.obsessiontelescopes.com/telescopes/UC_18_gallery/images/IMG_3083.jpg

The who sequence of OUC photos is here: http://www.obsessiontelescopes.com/telescopes/UC_18_gallery/index.htm#9

Time to start my homework in earnest!

Cheers
Chris

[Radar]

Interesting that the primary mirror isn't directly in the centre. So does this mean that the secondary is not exactly in the centre of the spider?

Ray

[omaroo]

Interesting that the primary mirror isn't directly in the centre. So does this mean that the secondary is not exactly in the centre of the spider?

Ray

LOL! The mirror is definitely in the centre of the optical train Ray - it just isn't centred in the rocker.

[omaroo]

Step 1: Mirror protection and transport.

Given that these mirrors will not form part of the permanent structure of the scope and will be inserted before each viewing session and removed after, they need to be protected in transport. There are several thousand dollars-worth of glass here - so I want them safe.

I've built the first of two boxes which will stack and be locked together for transport. The bottom has a raised section which will hold the mirror up off the bottom. There is good room at each corner to be able to curl your fingers underneath to safely grip and lift the mirror out. I'll be covering the interior in felt - which will close the gaps down the side and protect the sides. The wood I used is 2cm-thick solid jarrah - nice and solid and very pretty. Brass screws finish it off.

I intend to make elasticised soft acid-free "swimming caps" to cover the mirrors to protect them from dust and being accidentally touched.

Another thought... I'll see if I can incorporate a peltier-cooled airstream into the boxes somehow. I can get this going in the morning and have their core temps down to ambient before I go out and insert the mirrors....

Cheers
Chris

http://www.omaroo.net/albums/album46/DSC_2696.sized.jpg

http://www.omaroo.net/albums/album46/DSC_2699.sized.jpg

http://www.omaroo.net/albums/album46/DSC_2698.sized.jpg

[orion]

I will really enjoy seeing this come to life.

[Radar]

LOL! The mirror is definitely in the centre of the optical train Ray - it just isn't centred in the rocker.

Woops! :duh:

Wasn't sure if there was some kind of wierd optical thing I'd never heard of being used here.


[i][b]Another thought... I'll see if I can incorporate a peltier-cooled airstream into the boxes somehow.


Great idea Chris.

[Tenacious Del]

what will they think of next? inspiring project omaroo, good luck with it :thumbsupmate:

[AstroBob]

not much I can say here except "wow!". good luck with building it mate. :thumbsupmate:

[omaroo]

Thanks all :)

Focusers -

I bought (or more accurately, Jenny bought for me) two Bintel (TS) 10:1 Low Profile Newtonian focusers for the project. They have 37mm travel so should be nice. They're a tiny but heavy but are good value.

I've reversed one of the focuser shaft assemblies so that the slow focusing knobs are symmetrically presented for the user. The great thing is that as you turn both the same way, the tubes rack in and out in the same direction on either side :) Nice!

http://www.omaroo.net/albums/album46/focusers.sized.jpg

[omaroo]

Rocker Box -

Two long rails are 755mm inside edge to edge, two short are 420mm. Aluminium rail will form frame under the sides which will hold the two separate mirror cell assemblies. Edges are rebated so that the finish is nice and neat. Jeez this jarrah wood is tough - it's like steel to cut. Stainless screws will hold it together - and the corners of the frame will be either tigged or bolted.

Mirror templates are 395mm between centres.


http://www.omaroo.net/albums/album46/siderail2.sized.jpg

http://www.omaroo.net/albums/album46/rockerbox.sized.jpg

[wakaleo]

Lookin' good Chris. I'll be following your adventures too!

Jim

[Mason Dixon]

This seems like a really interesting project, has any progress been made?