• Greg Babcock's Astronomy Website

• Tube Service Co. - Supplier of Seamless Aluminum tubing

• Parallax Instruments

• Zambuto Mirrors

• Astro Systems

• Teeters Telescopes

• Equatorial Platforms

• Battery Station - for gel cell batteries

• Rose City Astronomers

• Mel Bartel's Diagonal calculator

• McMaster Carr

• Reid Supply

• Carbon Fiber Tube Shop

• Cloudy Nights Forum

These three articles are a great review of why and how to use fans to cool your primary mirror, by Gary Seronik and Byran Greer

Article about cooling your primary mirror - Part 1
Article about cooling your primary mirror - Part 2
Excellent article on fans and cooling