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first light with unfinished 12" Truss dob.


cassiewoofer

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Well I've finally finished the 12 inch build! The 9 point mirror cell isn't as beautiful as many I've seen but it works. Maybe post fotos next time the mirror's out.

 I definitely learnt loads from the previous solid tube builds, and the trick of using large circle diameters for the altitude bearing surfaces really makes a difference in the size of the mount. I've welded the mount from scrap speedframe.... 1mm steel square section.

I'm particularly pleased with the curved sections, which involved a technique more commonly used in wood. Just angle grind cuts at the required distance to generate curve and bend inwards clamped to the plywood circles and spot weld. It's functional but will get some mat black paint on all important parts in the near future.

 The azimuthal base is running on skateboard bearings, and I definitely need to improve the friction/clutch mech. which is currently just the central bolt tightness.

 Anyway, here's hoping for clear skies over the christmas break!

Must just add that I am tempted to go to a more conventional 3 vane spider having read some stuff on here recently.

Thankyou all for your encouragement and help!

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post-14797-0-82827900-1387365430_thumb.j

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Thankyou,

..................... yes stability! well since these pics were taken, I've added a strut between the two verticals, half way up. which has improved matters. Also I've added three height adjustable feet to the three corners that stick out a bit.

 It's definitely sturdy enough. The main problem I want to solve is preventing the way it springs back a bit from the position you turn it round to. Altitude setting is on four PTFE bushes running directly against the plywood edges at the moment, but I might do what others do on here and get some iron on formica strip to coat the plywood.

i'm hoping to borrow a CCD camera this holiday so if we get any clear skies I'm hoping to capture Jupiter. Just need to get my head round loads of flippin' software! 

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Have you tried using three ptfe bushes rather than four?

Thanks JRM

Funny you should say that CTD, I was thinking along those lines when playing with the setup. As you can see I'm very fond of the three points of contact (which define a plane in mathematics) And my last 10 inch had a bit of a wobble on 4  pads because of the inaccurate cuts/mounts to the plywood.

 I'l probably try 3 over the christmas break.

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Thanks for all the encouragement. Regarding build photos, I never took any!......... However, I will be dismantling some parts in the future so will try to explaining the build as comprehensively as possible. 

 It's working beautifully and was out last night initially trying to get images of Jupiter...... However after getting the planet on the webcam I realized I was not going to get anything decent and I was missing the great seeing so decided to get the gloves on, put the computer away and just enjoy the views!

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