Amazon.com : Astromania Adjustable Guiding Scope Ring Set with Plate - 80 mm Inside Diameter (Pair) - for Telescope Tube Diameter or Finders 53 to 79mm : Electronics
60mm CompactGuide scope with PLUS 80mm guide rings: Buy online | Primalucelab.com
Autoguiding a Telescope for Deep Sky Astrophotography (Basic Setup)