August 26, 2012 


Astrophotography may involve exposures of several minutes or more. Since the sky appears to move due to Earth's rotation, such exposures often require some way to track the sky's movement during that exposure. This article describes building and using a simple, relatively inexpensive "Barn-door" tracking mount based on an article by Gary Seronik in the June 2007 issue of Sky and Telescope magazine, page 80. Since reprints of that article may  be hard to obtain, you can view the plans online at

I will not attempt to duplicate those plans here in my article. But I will add my comments and photos of my implementation of the plan. Be sure to consult the plans for construction details and important points not covered here.

The Barn-door mount gets its name from the two plates of plywood with a hinge connecting them, like a barn-door. We see it pictured above installed on an old Celestron equatorial wedge, which has adjustments for altitude and azimuth. The mount can also be placed on a heavy-duty photo tripod. A gear head on the tripod with altitude & azimuth adjustments can make polar alignment much easier.

 The view above shows the tracking mount and equatorial wedge on a very solid Celestron Tripod.