Saturday, September 18, 2010

Binocular mount

I finally made a binocular mount for my faithful Celestron 15x70s.  It's a parallegram mount with five degrees of freedom: (1) the whole thing swivels where it attaches to the tripod, and (2) goes up and down; the binoculars then swivel (3) up and down and (4) left and right, and (6) can rotate a bit side to side.  It sits on a very short tripod as it's designed to be used by seated me and standing children.

Total cost was quite low.  The long dark pieces of wood are pieces of a recalled cherry crib that was being given away for scrap wood on Craigslist.  Most of the rest of the wood is 1/2" Baltic birch leftover from the 6" F/5 made for my friend, for some parts laminated to approximately 1" thickness.  There are a bunch of 1/4-20 carriage bolts and knobs from Amazon's Industrial and Scientific store.  I had some leftover PTFE for the main azimuth bearing, and purchased some cheap PTFE washers from Amazon for a low price (the price has now gone up by an order of magnitude).  The hideous counterweight is a bubble wrap envelope full of sand, duct taped all around.  The first iteration used a brick, but I was worried that a kid might whack someone on the head with it, and so bubble wrapped sand is better.

It was pretty easy to make.  I used a router for some round pieces, like the semicircular binocular attachment, but polygonal pieces cut with a hand saw would have worked just as well.

The azimuth bearing was the most complicated part.  It's basically scaled-down Dobsonian azimuth bearing: there are three PTFE pads inside, which ride on a CD (two out of my three Dobsonians ride on vinyl records).  This then bolts to tripod platform.

The tripod is entirely home made, too.  I once ended up buying twelve feet of 1.25" PVC conduit at Home Depot or Lowes because I needed a few inches worth for a focuser.  I expected I would eventually find a use for it, and hereby I did.  The tripod platform is a round piece of 1/2" Baltic birch, with some square poplar rods glued underneath, between which the PVC legs sit, attached with a carriage bolt.  To keep the legs from sliding apart too much, I glued three pieces of webbing, I think scrapped from a car seat or feeding seat, glued to the legs with Shoe Goo, and then screwed into place for additional safety.

I may later make a post with more detailed photos, but it was all fairly simple.  One thing that took me a bit of time to figure out is the brown block of wood that the semicircular binocular attachment attaches to.  It is a rectangle of cherry, with an up-down 1/4" hole and an across 1/4" hole.  The latter hole has a permanently mounted carriage bolt.  I used a 5/8" Fortsner bit to dig a deep well for the head of that bolt so that the up-down bolt would be able to sit to the left of that head.  I then filled the well with JB Weld for strength.


  1. Impressive! Though I do have to agree with you that the counterweight is aesthetically unappealing, to say it politely. lol Other than that I think it looks quite neat. The design, the different woods used, and the tripod made out of different material, gives the mount character.

    Seeing you do all these DIY projects makes me want to do some.

  2. Maybe what I could do to improve the look is put on a weight-lifting weight, and then wrap it with bubble wrap or some other foam?

  3. I glued pieces of oak on either side of the central column, to give it more resistance to torsion. The torsion was making the binocular view take a while to settle down.

  4. While the central column still has some torsion, the viewing is now much steadier, and the remaining torsion doesn't seem to be a problem.

  5. That's good you bettered the torsion. Did you decide to go with the bubble wrap or foam with the counter-weight?

    I didn't know what should've been with it.