Gary's Motorized Big Bino Chair

Construction of Bino Mount

by Gary Honis

Parts for Binocular Mount:


In the design of the binocular mount, I considered use of a parallelogram mount that could be attached to the chair base. I decided against this because of the additional weight this would add to the system and need for portability and quick setup. The bino mount I built is relatively light, requires no modification to the reclining chair and can be adjusted for the size of different observers. This design works well for a single observer.

Altitude (up-down) position is controlled by the observer shifting his weight and by leg and foot pressure on the reclining chair. This is how these reclining chairs are designed. I used a chair that was given to me by my daughter that she got free for purchases made from a supermarket. Look for a chair that is comfortable, well built and easy and smooth to operate when reclining. My daughter said she has seen the lawn chair for about $50 at Walmart, "Bed Bath and Beyond" and "Big Lots".

With the additional weight that the binocular mount and large binoculars add to the system, I use bungee cords on the front of the chair to assist with returning to the upright position and also to balance the large binoculars on the mount. Use of the bungee cords instead of counterweights, minimizes the weight of the system. Minor altitude adjustments while observing can be made by lifting and lowering the binoculars slightly.

Right Ascension (left-right) position is controlled by a DC powered reversible and variable speed drill. The drill has a switch that is activated with the thumb and forefinger to change direction. How hard you press on the drill's trigger determines the speed. The drill chuck also has a clutch that I found works best at a high setting for my system. The binoculars can be rotated on the computer tray for observing to a certain degree, before moving of the chair with the drill drive is required.

The position of the binoculars from an observer's eyes can be adjusted as needed while observing since the binocular support (computer tray) is spring loaded. The binocular mount can be swung upward out of the way for sitting down or getting up off the chair.


1. Drill a hole in the center of the computer tray for mounting the 25X100 binoculars on its center post with 1/4-20 bolt and washers.

2. Make four spacers for mounting the metal pipe arms to the side of computer tray. The spacers for my chair needed to be 1 1/4 inch. I used a 1.5 inch diameter hole saw in a drill to make 8 spacers out of 5/8" plywood. I stacked two of these spacers for the needed 1 1/4 inch spacing:

3. The sliding computer/keyboard tray comes with four brackets for mounting the tray under a desk top. I removed two of the brackets (back) since they were not needed. I used the other two brackets (front) for mounting a long spring. I used the existing holes at each end of the sliding tray brackets to install four 3/16" by 3' bolts for mounting to the conduit pipe arms.

4. Cut the 10 foot conduit pipe into three pieces: two 4-foot sections and one 2-foot section. I marked the location of the holes needed in the two 4-foot pipe sections to line up with the holes for the 3" bolts in Step 3. Drill these two 3/16" holes through each pipe section as shown below. Attach two 1/2 inch EMT to EMT Pull Elbows to the end of the 2-foot pipe.

5. Complete assembly of the tubular frame by installing the spacers and metal pipes and tightening all screws of the EMT to EMT Pull Elbows:

6. For attaching the binoculars to the computer tray, I made two spacers out of 5/8 inch plywood using a 1.5 inch hole saw and a 2 inch hole saw. Add felt strips to the front and back of computer tray where the binoculars make contact to avoid marring the binoculars. Tighten just enough to allow the binos to be rotated left and right:

7. Place two 1/2 inch conduit hangers on the tube assembly 23 inches from the binocular end of the tube assembly.

8. Use a 1x13/32x1/16 flat nylon washer and a stainless steel washer between the 1/2 inch and 3/4 inch conduit hangers and fasten with a 1/2 inch long bolt and locking nut. The locking nut will keep the joint from coming loose in time as the bino mount is rotated.

9. I installed two long springs from the front brace of the computer tray to an existing bolt on the back end of the tray. The tension of this spring helps support the weight of the binoculars when they are pointed near zenith.

10. The Binocular Mount is now complete! It can be placed on the the chair with the two 3/4 inch conduit hangers positioned about five inches from the top of the chair on the chair frame and fastened with wing nuts. I used rubber grippy material found in dollar stores on the tubular frame under the conduit hanger to prevent marring of the chair frame and to keep the conduit from slipping out of position:

11. The completed bino mount attached to the reclining chair. The bino mount can be left on the chair for transport; it folds flat with the chair when it is folded.

12. Bungee cords were added for the optimum motion of the chair in altitude. I used two 18" cords (blue) on the front and two 40 inch cords (yellow) along with two 32 inch cords (Green) on the back.

Next Page - Setting Up For Field Use

Big Astronomy Binoculars - Large Astronomy Binoculars


To My Astrophotography & Digital Imaging Home Page


Detailed procedure for drill-powered astronomy binocular chair.

Binocular mount for Apogee 25X100 large astronomy binoculars.

Comfortable observing with big astronomy binoculars.

Reclining chair for large astronomy binoculars.