Now this is going back a ways, but I constructed a simple equatorial
camera mount from instructions in Sky and Telescope or Astronomy ~20
years ago. Two pieces of plywood joined at an edge by hinges are folded
to resemble a book. Sighting along the hinges provides polar
alignment. The manual drive is provided by a 1/4 x20 bolt threaded
through a t-nut mounted in the top board. The distance this is placed
from the hinge centerline determines the rpm the bolt must be turned to
match the rotation of the sky. You can mount a ball head on the board
to carry the camera. This mount is then set on a tripod to allow polar
alignment.
As I recall this arrangement worked well for exposures up to 5 minutes
or so with a 50mm lens. The initial alignment is the most important
factor in image quality. It's no substitute for a proper telescope
mount but $5.00 at the hardware and an hour or two of work will get you
something to work with.
If anyone is interested I can make a drawing and email it as a jpg
file. Contact me off list if you're interested.
Mike Luks
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