Science In Your Hands!

4 Inch Telescope Mirror Blank

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Quick Overview

A 4 inch telescope mirror blank is great size for beginning and experienced amateur telescope makers.

4 Inch Telescope Mirror Blank

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A mirror blank is the key item that an amateur telescope maker will need to begin building a reflecting telescope. Our blanks are made of a low thermal expansion borosilicate glass called SUPREMAX® 33. They are also precision annealed to improve resistance to thermal shock and overall durability. SUPREMAX® 33 has replaced Pyrex® as the standard for telescope mirror glass as the production of Pyrex® mirror blanks has stopped.

Additional Information

Glass Type Supremax® 33 Borosilicate Glass
Diameter 4.0 in.
Thickness 1.0 in.
Coefficient of Thermal Expansion 3.25 x 10-6 K-1 (20-300°C / 68-572°F)
Density 2.2 g/cm2
Technical Information Supremax® 33 Borosilicate Glass
Weight 1.2 lbs

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