Equatorial Platform for 18-inch Dobsonian   HOME INDEX BACK NEXT

These photos show the equatiorial platform for my 18-inch Dobsonian telescope. The hardware, stepper motor, electronics, and basic design instructions were purchased from TL Systems. To make the platform as sturdy as possible, I modified it by using a wooden wedge to set the roller bearings at an angle 41 degrees, my approximate latitude here in southern Connecticut. However, I have been able to use it in northern Vermont, at a latitude of 45 degrees, by propping up the north end of the platform with some wooden wedges.







  The equatiorial platform provides continuous tracking for 50 or 60 minutes.
  The ground board of the platform has a stepper motor and roller bearings tilted at 41 degrees, the latitude of my location.
  Two segments on a circle on the base represent the "polar axis." The one on the left rides on a roller bearing, and the one on the right is driven by the stepper motor.
  The handbox has a dial to adjust the tracking rate, and a toggle switch for panning east or west.
  The drive wheel of the stepper motor turns the polar axis segment, which is covered with a strip of leather that provides smooth movement.