Adding an Azimuth Setting Circle to my Apertura AD-8 Dobsonian Telescope
This page is intended for a certain audience who are already familiar with the Dobsonian telescope and the azimuth setting circle. This describes how I added an azimuth setting circle to an Aperetura AD-8 telescope purchased from High Point Scientific. The setting circle was purchased from Mark at AstroGoods, it was custom made to my order.
Photos.
This photo shows the setting circle in place, lying on top of the ground board. The big silver circle in the center is the roller bearing system -- an aluminum plate on the bottom, roller bearing plate sitting on the aluminum plate, and another aluminum plate (the one shown here) sitting on top of the roller bearing.
This photo shows for 5mm Teflon pads I had left over from another project. I laid them evenly around the inside of the circle to (1) hold it in place and (2) put friction on the circle so, after I set it, it would stay in place until I moved it. The circle hangs over the ground board about 1/8 inch, which is enough for me to grip it and move it.
Here is a close-up of one of the Teflon pads, now screwed into place. Notice it is ever so slightly cocked so it is against the setting circle, thereby putting friction on the plate.
I used a 7/8-inch hole saw to cut out this observation hole that lets me see the degree markings on the circle. Used a fine mater saw to finish the cutout. Applied four coats of poly after this picture was made -- seal the ground board against moisture intrusion.