(Special thanks to Brent Parrish for his interest in sharing his hard work. Brent gave me permission to publish his new article on how to make a usable mount for big astronomy binoculars.  As anyone who has ever used telescope binoculars for a length of time knows, the challenge is to hold without shaking!  Not only that, but to have a comfortable way to view, without twisting your body – well, that’s a challenge with almost any store-bought system. Tripods just don’t cut it.  So – take a look at a terrific solution to a painful problem!)

An Affordable Binocular Mount

Having been bitten by the astronomy bug, I’ve been champing at the bit to buy a telescope. I decided to talk to a few amateur astronomers and read a few books before I made the leap into an expensive purchase. It became clear that it might be a good idea to learn the sky first and a good pair of astronomical binoculars should do the trick. I’m glad I took this advice. Astronomical binoculars are good for wide-field viewing and offer a good starting point for learning how to align yourself with objects in the sky. Additionally, large apeture binoculars are an excellent way to scan the sky in concert with a telescope.

I settled on a pair of Celestron Skymaster 20x80 Binoculars. I appreciated the fact that the Celestron’s came packed in a thick foam and a nice big box, but most importantly the optics are good. Eager to view the night sky with my new binos I realized that it would be nice to have some kind of mount for vibration-free viewing. I determined to mount my Celestron 20×80s to an inexpensive digital camera tripod I had bought a short time ago.

Removal of the hinged camera mount on top of the Carson tripod was accomplished by using an X-ACTO Fine Razor Saw. A razor saw is good for cutting plastic and was perfectly suited for the job. In the above photo you can see the protruding 5/16″ diameter 1″ T-Nut where the mount will be secured. Also, a 1/2″ hole directly behind the T-Nut is visible and will be used as a registration hole for the wooden mount. Adhesive-backed aluminum oxide sandpaper was also affixed to the top of the tripod mount as a frictional surface for securing the wooden mount.

Following removal of the hinged camera mount, an oversize hole was drilled through the top of the tripod mount for a 5/16″ diameter 1″ T-Nut. It was a tight fit to get the T-Nut into the hole from underneath the mount, hence the short length. The hole was offset from the center and is located toward the front of the tripod. A large rubber and steel washer was used to help dissipate the pressure when the wooden mount securing knob is tightened.

The dimensions of the wooden mount are roughly 9 1/2″ x 7 1/2″. The hinged Rigel Quikfinder mount stands approximately 6 1/4″ high. 3/4″ birch plywood and poplar stock was used for construction. A 3/4″ diameter Forstner bit was used to countersink a hole for the mount-securing knob to a depth of roughly 3/8″ on top of the custom bino mount. Countersinking is necessary since the securing T-Nut mounted underneath the tripod mount is only 1″ long. A 5/16″ hole was then drilled through the countersunk hole. The rubber pad from the discarded tripod camera mount was salvaged and acts to hold a retaining clip around the bincoluar-securing knob. This prevents the knob from falling out when the binoculars are not mounted.

A 1/2″ dowel center was used on the tripod mount to precisely mark the registration hole on the bottom of the wooden mount. A 1/2″ hole was countersunk into the bottom of the wooden mount and a 1/2″ oak dowel was glued in place.

In the above photo is shown the 1/2″ oak dowel on the bottom of the wooden mount which acts as the registration pin. 3/4″ Forstner bit was used to countersink a hole for the 1/4-20 threaded male binocular securing knob to a depth of 3/8″. A 1/4″ hole was then drilled through the center of countersunk hole. The 1/4″ stud of the securing knob threads into the binocular’s vertical tripod adapter post and secures the binoculars to the wooden mount. A small square of 1/4″ baltic birch plywood was glued to the bottom of the wooden mount to provide a shelf for the hinged Rigel Quikfinder mount to rest upon.

A Dowl-It Jig was used to center a hole on the edge of the wooden mount which accepts a threaded insert for the knob that secures the hinged Rigel Quikfinder mount. The jig automaticlly centers the hole and steadies the drill bit so the hole is square to the edge.

The shop-made jig above is the one to best ways I’ve discovered to install threaded inserts. Typically, folks will use a large flat-head screw driver to install a threaded insert and then quickly discover how difficult it is to keep the insert square in the hole, meaning it goes in cock-eyed! The jig above prevents this dilemma by using a long 5/16″ stove bolt with two 5/16″ nuts (one nut acting as a locking nut) which threads into the thread insert. Using a wrench or ratchet to turn the stove bolt, the threaded insert will thread easily and stay vertical during installation.

Above is the first mounting of the binoculars. The hinged Quikfinder mount makes it easy to secure the binos to the mount. Also visible is the securing knob for the Quikfinder mount, which threads into the previously installed threaded insert, and the sercuring knob below the custom mount which threads into the binocular’s vertical tripod adapter post.

A simple cabinet hinge was used for the Rigel Quikfinder mount. The Rigel Quikfinder has an adjustable reticle that allows you to more precisely point your optical device at objects in the sky. Powerful optics see a very small sliver of the sky and a device like the Quikfinder can greatly aid in aligning your view to the desired object.

Celestron Tripod Adapter Weakness Unveiled

While observing Jupiter one fine August evening, I found that my binoculars had come off the mount in my hands — fortunately! I thought that the securing knob must have come loose. To my surprise I discovered that the part below was the culprit.

The above part screws into the bottom of the Celestron Binocular’s vertical tripod adapter post and is used to secure the binoculars to the tripod or desired mount. There’s an inherent weakness with this design and it has to do with the multi-threaded part that threads into the center of the knurled disc. (See below)

The part in question has a smaller diameter non-standard thread on one end that screws into the tripod adapter’s vertical post. The photo above shows the broken part to the right of the knurled disc in two pieces — should be one! The thread only extends less than 3/8″ into the post. The other end of the part has a larger diameter thread that screws into the knurled disc. Additionally, the part is bored out internally for a 1/4-20 thread. This is where the weakness lies: since the small thread only extends into the post a very short length and the part is bored out internally, any sway or torque on the post will easily cause the part to break. You can see in the photo above how thin the wall is from the internal thread to the outside thread. This could lead to disaster and almost did! Fortunately, the binos were in my hands when the part failed.

I thought about getting a new part from the manufacturer, but then I simultaneously thought that if it happened once it would happen again. My solution was to punt the small multi-threaded part and knurled disc and provide a more stable and rigid arrangement for mounting the binoculars. Unfortunately, the inside diameter of the vertical post was a non-standard size — around 11/32″. This was close enough to 3/8″ standard size and I decided to tap the post using a tap and die set. Additionally, a 3/4″ thick square of oak measuring 2″ wide by 3 3/4″ long was glued to the top of the wooden mount. A 5/8″ hole was drilled into the oak block for the vertical tripod adapter post. This design greatly improves the stability of the post.

A hex head insert was installed to provide a 10-32 thread for a clamping knob. A hex head insert can be installed with an allen wrench and is easier to thread than a standard threaded insert. The clamping knob is located in front of the newly added oak block and helps to reduce the binocular’s tripod adapter post from moving left or right.

I was unable to find a male knob with a 3/8″ stud and was required to make my own. A 3/8″ diameter carriage bolt measuring 2 1/2″ long was used for construction of the knob. A one inch long piece of oak dowel was centered drilled using a 3/8″ bit and a drill press. A square piece of 1×2 pine was used for the knob. Before cutting the 1×2 to shape, a 7/8″ Forstner bit was used to countersink a hole to roughly 1/4″ depth and then a 3/8″ drill bit was used to drill a center hole in the countersunk hole. A chisel was used to square out the top of the 3/8″ hole for the square portion of the carriage bolt. Epoxy was used to secure the 2 1/2″ carriage bolt in the pine knob and the oak dowel was secured with carpenter’s glue. A 3/8″ nut was used to clamp up the assembly while the glue cured.

It was necessary to tap the Celestron Skymaster’s vertical tripod adapter post for a coarse 3/8″ thread using a 3/8″ tap. The post was threaded to a depth of roughly 7/8″. Be patient when tapping a new thread if you have never done it before. Too much torque and pressure can snap the tap. The secret is to turn the tap a 1/4 to 1/2 turn, depending on the hardness of the matrial, then back it out a few turns to clear the shavings, then keep repeating the process. It takes some time and elbow grease, so once again be patient and apply only enough pressure as needed to hog out the material. It took about 15 minutes to tap the post to a depth of 7/8″.

Not shown in the photo above are the extra steps taken to protect the lenses while threading the post. Painter’s tape was used to secure the lense covers and the binos were then wrapped in visqueen plastic with only the bottom of the vertical post poking through the plastic. Additionally, a two foot piece of 1×2 pine stock, with a 5/8″ countersunk hole on one side and a 3/8″ center hole drilled in the center of the 1×2, was used to steady the tap vertically while threading the post. The 1×2 is placed perpendicular to the post, with the post being inserted into 5/8″ hole. The tap was then inserted into the 3/8″ hole which aided in keeping the tap square to the post.

I decided against the use of a lubricating oil while threading the post. I can’t think of anything worse for optics than oil and metal shavings! Great care was taken to ensure that nothing got to the lenses. I also used some compressed air to blow out the shavings from the post and shavings that had collected on the bottom of the binocular’s vertical post securing knob with the lenses covered. DO NOT USE COMPRESSED AIR TO CLEAN YOUR LENSES!

Conclusion

Now that the teething problems have been resolved, the custom binocular mount serves it purpose well. The solid 3/8″ bolt and the stablilizing oak block firmly secure the binos to the mount with little risk of failure. I couldn’t be happier with my Celestron Skymaster binoculars regardless of the aforementioned weakness with the tripod adapter. This is not the ultimate setup, but a good start. Due to the inexpensive quality of the tripod itself, vibration is still an issue, but it beats holding the six pound binoculars by hand. It was a real thrill too see Jupiter and her four major moons for the first time. Yep, I’m hooked now! Looks like my next project might be a parallelogram binocular mount. Stay tuned!

(Thanks Brent! We are looking forward to your next installment. In the meantime, you are invited to check out our selection of telescope binoculars for your viewing pleasure.)

This entry was posted on Monday, September 14th, 2009 at 12:04 pm and is filed under About Telescope Binoculars & Astronomy. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.