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Building this
mount was great fun. A bike wheel fastened to a sheet
of plywood and braced on a couple of trestles so that
the wheel spindle (The RA Axis) points at the pole. I
used the equatorial wedge from my first project to achieve
the correct angle.
The wheel only rotates a few degrees which
is equivalent to 15 mins of viewing time. Rotation is
achieved by winding a 2mm pitch threaded rod at 1 RPM.
The purple wheel is turned by hand to match the motion
of the second hand of a watch.
I had some good results from this contraption
in the 2 weeks my wife would let me have it in the garden.
Eventually though the grass started grow and it had to
go.
Still, at a cost of £2.00 for the wheel
(everything else was in my scrap box) it is yet another
low cost approach.
If I was to do it again, I'd use a 0.5mm
thread pitch rod and a much smaller wheel. |
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Some of
the results from the tracker
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The wheel actually worked well.
The problems with these images are: |
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1.
Too much light pollution;
2.
A badly focused lens on the camera - most visible in top
image. The lens won't focus at infinity;
3.
The mounting is unwieldy. But if you live in a rural area
with some unused space in the garden then you could do
much worse than a nice alloy bike wheel set up as a permanent
mounting for your astro camera. |
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