Dave's 16 Inch Binocular Telescope Page

This binocular telescope was built by Chris Redshaw of Tauranga New Zealand, it has two 13" mirrors that where ground by him. He's a fitter and turner by trade so the mechanics of this project weren't to daunting for him.

These are some notes from Chris about how he made this binocular

My13inch binocular telescope.

Grinding

the only strict requirement that you have to watch is that the focal lengths be within 1% of each other. Having only made an 8” before I though this might be difficult, so after hogging out I swapped the mirrors over and did a couple of wets this was repeated with every grade of abrasive I’m not sure if I was wasting my time or not the end result was the mirrors finished within 3mm focal length of each other how ever it consumed a lot of extra time. Foucault test is interesting, but if you can’t leave the setup in place it can be annoying.

The tubes

These are 8”apart; the eyepieces are mounted in holders that are hinged with the centre at the mid point of the tertiary mirror this lets the eyepieces move to accommodate for eye spacing. The equatorial table is driven by a hydraulic ram powered by an accumulator; the speed is controlled by an adjustable restrictor on the exhaust side of the ram, when the ram reaches the end of its stroke you have to pump oil into the exhaust side to return the table. It’s a very cheap way of driving the table, but not perfect. The rods on the sides of the tubes are for collimation of the primary mirrors while looking through the eyepieces. The end result of all this hard work that you will never go back to one eyepiece observing.

Chris Redshaw :-)