Easy To Build Binocular Chair
By Greg Walton (MPAS / ASV Member)
Date 12 February 2010

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Most Bino’s are designed to look at the horizon (Terrestrial) very few come with 45 or 90 degree eyepieces and these are very costly. So I had to come up with some way of holding the Bino’s and be able to look through them at the zenith (straight up). First I tried the camera tripod but these were too low and hard to aim at the object, plus I would end up with a bad neck trying to look through them. The second thing I tried was the trick of looking down into a mirror laid on a table, which was much easier on the neck, but my arms quickly became tied. Also the sky was up side down, and all the stars were double stars because, I used an ordinary mirror that was aluminized on the back instead of the front. The third thing I tried was to lay on my back, and rest the Bino’s on my head, this worked best so far, until I wanted to look at an object close to the horizon.

I then thought I should get a declinable car seat and put it on a swivel base, then motorize it all and mount the Bino’s on a bracket in front of my nose. With a push of a button I could move around the sky. But it all looked like too much work.

Then I came across a metal framed reclinable chair in an Opportunity shop for $30 and it had a swivel base. I thought to myself, that’s it, I can make this work. I would not need electric motors; my legs can do the job of steering the chair. So I dragged it home and fitted a bracket to hold a pair of 80mm Bino’s. I also added a 300mm long spring with a diameter of 25mm at the rear to balance the weight of the Bino’s. (Photo 7) Then I found when I leaned all the way back, I could not lean forward again, because of the extra weight of the Bino’s. So I added a strong spring under the chair to help me lean forward. (Photo 7) I added 4 knobs to the mounting bracket, (Photo 8) so I could adjust the angle of the Bino’s quickly. I found as I lent back in the chair, I tended to slipped down lower in the chair. (Photo 1 to 5) I had to compensate by changing the angle of the Bino’s, so when the chair is all the way back, the Bino’s are looking straight up at the zenith. The chair is light weight in construction, so it’s easy to move around or take to a dark sky site. I thought about adding wheels, maybe when I’m 90.

I have also added a pair of 100mm Bino’s to one of these chairs and have spent many hours at a time looking at the sky with no ill affects. My only complaint is that every body who comes along wants to test the chair, and I can’t get them out. I have found these types of chairs are quite easy to come by at $50 and have bought 5 in the last year, so I am sure there must be a lot around.

I used 25mm U bolts to attach the balance bars to the steel frame, at the top of the back rest. By adjusting the tension on the nuts I can get the right amount of friction when adjusting to the desired angle. I bent the balance bars to a slight S shape, to make it easy to get into and out of the chair. The balance bars are made from 22mm round steel tube 1.5mm wall thick, and is easily bent or flattened in a vice. I am sure anyone could make this chair and improve upon it.

To Contract Greg, Phone 03 9773 0098 Mobile 0415172503