Mounts - Frank Johns

Go to content


Astro Equipment
Losmandy G11
The Losmandy G11 is mounted on a homemade steel pier.
After a few years the original Gemini I system suffered a number of failures and at great expense acquired the Gemini II. However this proved to be totally incompatible with the existing motors so it was returned to Losmandy.
I did get the dead Gemini I controller 'revived' but with the unreliability and a  loss of faith in the system, I looked around for an alternate.
I came across the OnStep unit, designed by Howard Dutton, which is an arduino based system mainly for DIY. However I located a commercial version from, and to further convince me the cost was probably only a tenth of the cost of Gemini II. Onstep has proved to be even more accurate with GOTO than I experienced with Gemini I.
The main counter balance weight is wrapped in rubber becauase of my tendency to crack my head on it in the dark. the brass weight allows for fine balance adjustment.

The OnStep kit for the Losmandy G11. The motors mountings were well designed and only took around 10 minutes to fit

Vixen Polarie
The Vixen Polarie is a replacement for the Astrotrac. It is compact and relatively light and so ideal for taking on trips overseas and where space/weight is limited.
The fairly heavy duty camera tripod was modified to enable reasonably fine adjustment to the pointing of the Polarie. As I already had a Canon right-angle eyepiece unit, a connector was made to mount this on the polar finderscope, which saves getting a crick in the neck. The red dot finder allows for very quick rough polar alignment and is then transferred to the camera for more accurate target alignment.
The thing which looks like a lens hood is in fact a homemade muff which will carry 1, 2 or 3 hand warmers to combat dew. Made of wetsuit neoprene it performs very well.
As far as performance is concerned with a wide angle lens on the camera, exposures of 10-15 minutes without star trailiing are perfectly possible.

Skywatcher 127
This mount is used for outreach work, often with the National Trust, but also with scouts/schools/etc.
Back to content