Binoviewer on small tripod

· 2 inch (minor axis) elliptical secondary mirrors have ¼ wave or better surface.

· Hinged lid protects optics for travel and is fixed for viewing at 135 degrees relative to the mirror faces by one bolt. The bolt serves double duty to secure lid for travel.

· Zeiss 7x50 binoculars are held in place by a central pillar and 2 small bungie cords.

· One elliptical mirror has 3 point adjustment to permit exact convergence.

· Viewing is comfortable – straight down at horizon and straight ahead at zenith.

· All wood parts are ¼ inch aircraft plywood. Baltic Birch or Fir Ply would work well.

· Recessed T-nut accepts camera attachment bolt on tripod.

· Central compartment between mirrors holds mounting pillar and bungies.

Bottom view showing adjusting screws

Observer’s view showing pillar detail

A lot of binoculars are taken to star parties together with lawn chairs, tripods with adapter brackets, parallelogram mounts and chest mounts, all intended to lead to comfortable enjoyment of the stars. These devices are little used and shaky hand held views are no better and soon the binoculars occupy an unimportant corner of the observing table.

Views through Canon binocs with stabilized prisms are remarkable but arm fatigue and neck strain remain as lesser issues. Sim Picheloup has invented a fold up rotating binocular chair with ingenious mount for the binoculars, allowing them to float in front of the observer at whatever position he desires. Arm strain is gone and the reclining chair eliminates neck strain. The observer, propelled on a turntable beneath him, by his own feet, has access to the entire half dome of the sky in comfort.

My compact binoviewer lets the observer look straight down when viewing to the horizon and straight ahead when viewing at the zenith, precluding neck strain. A small tripod as pictured provides a steady view with no vibration. The binoculars become unnoticed, and the observer can devote full attention to the sky. I expect removal of vibration, arm strain and neck strain, coupled with the observer looking comfortably downward while seated results in at least a 50% increase in information available at the eyepiece.

I recommend any of the three approaches above. What can be seen? With the 1940 technology Zeiss 7 x 50’s

Open clusters come into their own. Over 90 of the Messier objects as well as many NGC objects can be seen under a dark sky (the binocs reach mag 10.4) The milky way becomes a journey of many nights and the coal black dust clouds provide wonderful contrast to the star fields, given a dark site. The moon has many shades of grey and with a steady field, surprising detail can be seen at 7x. A lunar map proves nice to have while viewing – something not usually found when the moon is being “scanned” with hand held binoculars or arrangements which require continued arching of the neck upward. Company 7 sells Baader Planetarium solar filter material which is in a class by itself. A bit of cardboard engineering (see their instructions) will yield filters for the binocs. Before attempting to view the sun, be certain the filters fit tightly and no stray light enters the binoc objectives.

It is satisfying to take your entire observatory to the field under one arm. It is more satisfying to know there are hundreds of objects waiting for you. With a 4.5 degree field of view, goto systems are not needed. Your personal on board analog computer plus a good star map and a small red led light will open the door to the sky.

The cost of one moderate 2 inch eyepiece will pay for the binocs - $225.00 via Ebay, and another $100.00 will buy the secondary elliptical mirrors and miscellaneous supplies to make the binobox. The pillar I built to attach the Zeiss binoculars can be replaced with a tripod adapter if your binocs are threaded for an adapter to be attached. Here is a source for the elliptical mirrors. Here’s some information about the Jenoptem binocs, and here’s a commercial viewer – not sure their glass has as good a surface as the telescope secondary elliptical mirrors and without a means to adjust one mirror while the other remains fixed, you cannot “dial in” the view, resolving any convergence issues and setting the apparent depth of field of the view. The designs with a fixed binocular and moveable mirror, however, are inviting as you are always looking down at the same angle and from the same height, precluding raising and lowering the tripod central pier.

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