A short construction report by Werner Wöhrmann

December 2024

My 20 x 80 binoculars have a true field of view of only 3.2° (a full moon covers about 0.5°). Therefore, the area of the sky that is visible through the glass is not very large.

When looking for comets or galaxies, for example, which are often faint, you have to know exactly where to look for the object – this can sometimes mean a somewhat more time-consuming search.

That's why I came up with the idea of attaching a red dot finder to the binoculars, as I also use it on my telescopes. Even astronomy binoculars often do not have a mount for a viewfinder – so how do you attach the finder to the binoculars?

While combing through various small astro parts boxes (over time a lot accumulates), one or the other useful thing came to light.

A fastening element (binoculars, tripod holder, Carl Zeiss Jena Nobilem) for screwing binoculars onto a photo tripod was included.

Now an idea had to be developed and tried out with what was available.

The idea matured to turn this attachment over and screw it upwards to the joint rod of the glass with the tripod screw (normally the screw sits at the bottom of the tripod).

With the photo tripod thread opening pointing upwards, a normal finder shoe can then be screwed on with a photo screw. No sooner said than done – the finder shoe got a (halfway) central bore and was screwed to the Nobilem – and everything was prepared for the red dot finder. It can now simply be slid onto the finder shoe – that's how it should be!

The first practical test has already been successful and so nothing stands in the way of its use at one of the next kosmos-os "Sternstunden".