12.5 Inch Telescope Mirror Blank

• Schott BOROFLOAT^® 33 borosilicate glass
• Low thermal expansion
• plano x plano, straight sides
• virtually no bubbles
• 1" thickness

A 12.5 inch aperture telescope is a great size for amateur telescope makers who have previous successful experience in mirror making. The first thing you will need to make is your primary. or objective, mirror. With this top quality mirror blank and the appropriate abrasives, polish, and pitch you will be able to make a telescope mirror to your own specifications that can potentially out-perform many mass produced telescopes.

Our 12.5 inch blanks are made from Schott BOROFLOAT^® 33 borosilicate glass. The advantage to this glass is its low coefficient of thermal expansion which helps your mirror to stabilize quickly as temperature changes through a long night of astronomical discoveries.

Each blank is water-jet cut from stock 1" thick float glass. This provides a nice smooth finish on the side and a polished finish on each surface. They have straight sides, parallel surfaces and virtually no bubbles. You will not need to do any preparation on the side or backside of these blanks before you get started grinding the main face.