Hi folks - after months of waiting for things to arrive in the post...
I have finally motorised my Dob.
The aim of this project was not to be able to do long tracking
or take DSO pictures, but track long enough to
keep a planet in a camera viewfinder for more than 5 seconds,
and have a bit more stability than bumping with my clumsy
mitts.
Purists might notice i only have one 30cm azimuth track (what a cheapskate) This was most definitely a money saving plan -
bearing in mind that this gives at least 4 hours of tracking.
Here is a basic parts list:
Altitude bits
1x 0.45rpm dayton motor (altitude motor)
1x 128t 32p aluminium hub mounted gear (1 inch bore)
1x 1inch hub mount for above
1x 48t 32p 1/2 inch bore aluminium gear
1x 3/8" hub mount for above to attach to motor
Azimuth bits:
1x 0.5 rpm gearmotor (azimuth motor)
1x 16t 32p 1/4" mount gear
1x 30cm 32p acetal gear rack.
Sundry metal items for mounting
Control
2x 12v PWM motor controllers for speed control
2x DPDT cetre off switches for direction control
Jiffy box to stuff it all in.
For mine, i think the altitude gear ratio is too low, so
it moves the scope too quickly - but 48t is the smallest
i could get to fit on the 3/8" motor shaft -if it is too
much of a problem some re-engineering will be required.
Here is a quick video showing the bits and how they work:
http://youtu.be/0V4lAv7nrsc
Shamelessly plagiarized from a video
by "Dakota Starry Nights" on youtube
Finished just in time to see the first cloudy nights in a month :-(