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Chris Smale:
Busy building me a star-tracker. That's why I needed that worm/wormwheel-set I posted earlier.
The geared stepper has 1:100 ratio, the (self-made)worm/wheel another 1:157. That should be enough to slow things down.
Worm and wheel are pushed against each other with a controlled spring.
There's an adjustable green laser on board serving as 'Polaris pointer'.
There are 3 large and 2 smaller ball-bearings.
The unit measures 160x75x55mm(about 6x3x2 inches)
At the top of the smooth rod (on the right side) comes a small platform.
There are 3 large and 2 smaller printed parts.

A DC-version of this star-tracker will also be made.

The electronics for this tracker will be designed and made by Guy, our electronics guru.
PCB not yet in the drawing

I like the spring loaded worm idea.


This is what I'v got so far.
Works perfectly, not tested under stars yet. Still, one weak point has to be removed.

In the last pictures there's a 'dummy cover' on top, just to look inside while it's running. The real cover is on the right.

I really like the work you are doing and all the attention to details. Congradulations.

However, there is one thing I don't understand: what is the purpose of the shaft that sticks out right next to the motor? Would a camera not normaly be attached to the worm gear driven shaft only?

Paul Woodrow:

The wormwheel's axis is supported by two ball bearings. One ball-bearing sits at the bottom of the box and the other is pressed into the cover. On top of that axis(outside the unit) rests a large ball-head to support a camera or whatever small device.

Thanks for the comment.


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