The Barn-Door Tracker of the Jim Loudon Observatory

I got inspired when I read the article by Dave Trott in February, 1988 issue of Sky & Telescope magazine (additional article in the April, 1989 S&T) and I had to build one of these. This one is made of brass and walnut plywood left over after I built an 8" f/6 Dobsonian for Robert Haag (the "Meteorite Man"). The legs of the tripod are made of unstained maple. The tracking is very good allowing exposures of over 10 min with a 28mm lens and four to five with a 50mm lens. See these pictures of Hale Bopp and an image of Orion for examples.

Other good references for building a barn door tracker:
A version of David Trott's original article on his website
Single Arm Barn Door Tracker
Manually-Driven Barn Door Star Tracker (Scotch Mount)
Affordable Astrophotography With a Motorized Barn Door
Astrophotography Without a Telescope
Barn Door Tracker (Wikipedia)