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Scotch Mount

This is a mount I made for use with a camera in order to track the night sky. The mount is a standard scotch mount, or barn door mount, modified to accept a motor. The motor is 3V 1rpm which, when combined with 1/4/20 screwed rod, will move the scotch mount at the sidereal rate. The motor bracket, couplings and battery box are constructed from meccano. A design for the scotch mount can be found at the following web sites:

http://www.u-net.com/ph/mas/projects/scotch/scotch.htm - Detailed specs for a scotch mount

http://www.astunit.com/tonkinsastro/atm/projects/handscotch.htm - Hand driven scotch mount.

http://www.nightskypix.com/equip/ScotchMount.htm - Another hand driven scotch mount

Construction

Materials Required:

· 2 pieces pine timber, rectangular, same size
· Large hinge to join timber together
· ¼" threaded rod
· Cap nut ¼" for threaded rod
· Tee nut ¼" x 2
· 1 rpm motor, 12V or less with mounting holes >4mm
· Battery box to suit motor or DC adaptor.
· Ball mount for camera
· 2 rubber grommets as stoppers on the rods
· Meccano parts, 2x 150mm rods, 2x 25mm bossed circular brackets, 1x double rod connector

Cut the boards into 2x approx. 310mm x 100mm pieces
Attach the hinge to both boards
Drill a hole 290mm from the centre of the hinge Important: This must be exact.
Drill a hole here for the t-nut
Hammer the t-nut in
Drill another hole in the centre of the base board for another t-nut. This is for attaching a tripod
Screw the threaded rod into the first t-nut.
Add a cap nut to the top of the threaded rod so it will slide easily on the timber
Attach the motor shaft to the other end of the threaded rod using the rod connector. One end of the rod connector needs to be drilled out to ¼” to accept the threaded rod. The other end should fit your motor.
Attach the two rods to the underside of base board using the bossed circular plates.
Insert the two rods through motor mounting holes, so the motor can move freely up and down when the threaded rod turns. Use grommets on end of rods to prevent motor from falling off.
Attach battery box or use external DC adaptor.
Mount on tripod and test operation