Wide-Angle Binoculars for Stargazing
Someone on the cloudy nights forum found out hat you can use a teleconverter as a binocular with low magnification but high field of view. Due to a larger aperture, more stars can be seen on the night sky that with the naked eye. The Nikon TC-E2 is especially popular, due to its great quality and great price, since it fits only obsolete cameras that nobody uses any more.
Some of the forum users also created 3D prints to hold them. Because i don’t like the existing designs, i made my own. After some first concepts of a rigid binocular, where the inter-pupillary distance is adjusted by an eccentric ring, i settled on a laser-cut design. The teleconverters are clamped by means of a screw, so that i do not have to glue them in and the stresses are more uniform than with a grub screw. Interpupillary distance is adjustable between the teleconverter limit of 65 mm and a maximum of 90 mm 1. The design can be found under this thingiverse link.
I was able to get it laser cut from a small local model shop. Assembly was a bit difficult, especially getting good threads and i failed to make a nice looking glue connection. But it tunred out completely functional and is quite robust.
For the eyepieces i used some Schwalbe No.19 bicycle tubes. They can be folded over to provide a nice eye rest, but are a bit annoying when putting the lens caps on. I also use wings on the side, made from the same tube, but cut so that they are not a ring any more. They are just fixed with rubber band. It would be possible to glue them on, but then i can’t remove them when they become annoying and its even more difficult to fit the caps.
In the future, I am planning to get some lenses made by an optician that i can fit inside of the eyepieces to correct my eyesight, because wearing glasses destroys the wide angle purpose of the binos.
Here are some pictures:
notice the ugly gluing. The thread depth is also a bit shallow, i might use longer bolts later on.
the hinge
another look of the hinge
There is probably no person with such a distance, most people are well below 75 mm. But it was difficult to fit the hinge closer to the center line. In addition it also provides more space for the nose ↩︎