A "Yard Cannon" refractor mount

In the amateur astronomy community, long focal length (i.e. - long tube) refractor telescopes are semi-affectionately termed "yard cannons." They're long, they're bulky, and well - they kind of look like cannons in one's yard. So when I picked up a 5" diameter refractor lens about a month ago, I had planned on making a "folded refractor" - or one that bounces the light off a number of mirrors, making for a small, compact telescope.

Then the guy who sold me the lens found the tube and focuser....

So I thought, "Hmmm... I can spend a lot of time trying to figure out how to accurately bounce light off three mirrors, and subsequently lose a lot of photons in the process, or just build a huge freaking tripod/mount and have a yard cannon."

Clearly, as evidenced by the picture below, I opted for the latter:

So how did I go about building this monstrosity? Well, first off, I knew I wanted to be able to have the eyepiece, when pointed at the zenith, be at a relatively "viewable" angle. That necessitated a rather high tripod. But when balancing the scope, I also realized that if it were to be that high at zenith, then the radius arm of the eyepiece would be HUGE, and therefore mean I'd need a stepstool (ladder?) to see anything below 40 degrees or so. Not the greatest option!!

I made use of the CAD software that I have, and figured that by using counterweights in the right places, I could have a scope that keeps the eyepiece in relatively "normal" heights, and also not be so heavy or difficult to move. Well, it IS a little bigger than I'd hoped, but this scope is likely to be used more at home anyway, so it should work out fine for my needs.

The tube is placed in a plywood "box" of sorts, that has the radius of the tube cut into the ends, with a removable top. The top then has four thumbscrews that allow for tightening the scope in place, or loosening it slightly for minor balance adjustments. It actually balances across a pretty wide range before requiring rebalancing (I'd estimate 35-45 degrees or so). The finderscope is bracketed onto that box, and is high enough that I can still stand and not have to contort too much to point towards the zenith.

Note in the picture above, two 5 pound weights are bolted to each side of this box to counterbalance the rather weighty 'lens end' of the scope.

Some rather convenient PVC plumbing parts are used as the bearing surfaces, which then rest on nylon furniture glides. Very smooth movement - nice!

The handle is place so that when transporting the scope, it balances and remains level.

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One last thing: Please be sure to turn off your outdoor lights, or if you must have an outdoor light on, be certain it is a full cut-off fixture, and the minimum wattage required. No sense in lighting the underside of planes at night - it just ruins the night sky for everyone else! Besides, doing so really will save you money on your electric bills. For more information about light pollution, please visit the International Dark Sky Association.