As long as it's photo night . . .

Hello everybody,

Here is my 14.25" f7 Newt. I have posted a few pictures before but this is a "latest version" photo.

Matt

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Hi Matt,

That is stunningly gorgeous and very technical-looking all in one package.

Please say more on the contruction and materials for the various components. Does it easily come apart into something transportable? What parts are wood, metal, or other? It is an Alt-Az design? How are the movements?

I'd love to see photos from more angles.

Thanks for sharing...

Lee

Lee,

Thanks for the kind words. My creation is all plywood with the obvious exceptions of the truss poles and sundry hardware. The primary is 1979 vintage Coulter, made before their Dob mass production era. It disassembles completely and easily fits into a 1986 Nissan Sentra. The mount is alt-az, similar in design to the Giro (but a bit bigger, heh). Here is another picture, with more to follow.

Matt

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Here's a closeup of the mount. Pointing is courtesy of Wildcard's Argo Navis.

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Here's a closup of the bottom end.

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heh, well, the OTA weighs ~90lb or so, but the counterweights (100lb) and the mount (80lb) add up. It is an extremely mobile scope, but it does take ~1 hr to set up (and take down). But it is definitely worth the effort.

Matt

Lee,

You are correct, the heaviest component is ~40lb.

The pier is ~7" schedule 40 steel pipe. The azimuth pivot is based on a 3" diameter aluminum shaft topped by a Timken tapered bearing with an Aluminum "cap" to provide for preloading the bearing via a center bolt into the shaft. The az encoder attaches to this center bolt. The az axis rides on ~1.5" O.D. common sealed ball bearings on a "race" (3/16" aluminum plate)with a diameter of 14". The motion is very smooth. The only problem I have is that the center bolt loosens over time so I have to watch it closely. I am thinking on a fix for this niggling little issue. I know it might be hard to visualize, but I welcome any ideas. I might take the thing apart and post an exploded view picture if it would help.

Matt

Lee and Chuck,

Thanks again for the complimentary words. I see from the wonderful scope pictures posted here that I am not alone in my love for scope making!

Lee, I would consider motorizing the scope, if only the ServoCat was a little less expensive. For now the excellent accuracy of the Argo Navis and my muscle power will have to do. I must admit, there is something special about pushing the scope myself, although tracking would sure be nice.

I definitely plan on placing the scope in an observatory setting some day on a massive EQ mount (of my own creation, of course). The only problem there is with focuser position, so a rotating OTA would be in order. Or perhaps I might dedicate the scope to CCD planetary work. By that time (who knows how far off this dream is), CCD cameras should be really awesome!

Chuck, I have no real balance issues. I do hold on to the scope when changing EPs, but the ~1 lb EP weight range is not enough to upset the balance.

In the initial design, I was very close on the OTA balance, purposely making the thing a bit bottom heavy. I now regret this, as I have had to hide some lead CW in the top end. I should have trusted my math . . .

Also, the mount has a bit of "twang" in altitude. It is nothing serious, and damps out in ~2-3 sec, but it is annoying. I will be adding a thrust face to the alt axis at some future date. That is why the alt/az head is still only primered . . .

Matt

[jaw dropped to the ground] WOW! It's beautiful! Can I have it? How much do you want for it? Are you selling the plans? [/jaw dropped to the ground] LOL!

Bart,

heh heh, thanks, but it's not for sale. And, there are no "plans" in a real sense--I drew things up "on the fly," sometimes right on the plywood. I did make a few life-size "sectional" drawings of some parts as construction proceeded, but they are in no way organized! I would build something, decide if it "looked right," and then move on.

I spent more time weighing things on my postal scale to nail the OTA balance than anything else. And painting it by hand, that was rather time consuming.

Building this scope was definitely a labor of love, and as my first large scope project, *really* educational as well.

I hope to top it some day by building a 30" f3.5 Newt based on a Stabilite mirror (a Paracorr will be needed for this one!). My main design parameter is that no scope be taller than my eye-height at the top of my 4-step Little Jumbo ladder (98"), and a 30" f3.5 is about the biggest aperture that meets this limitation. I imagine a 6-strut minimalist, motorized everything (including OTA rotation) monster that moves in and out of its transporter under servo/RC control--a 4-wheel-drive telescope. I don't need no stinking transport handles!

Oh, and a trailer is in the future, too. And bunches of $ (hopefully) to pay for it all.

Matt