Mirror Lab
Build your own telescope from scratch
Start with Raw Glass
Begin with a glass blank—typically Pyrex for thermal stability. Common sizes range from 6" to 12" diameter.
Rough Grind the Curve
Using silicon carbide grits, create the parabolic curve. This is satisfyingly physical work as you shape the glass.
Fine Grinding
Progress through finer and finer grits (120, 220, 320, 500) to smooth out the surface while maintaining the curve.
Polishing
Switch to a pitch lap with cerium oxide. The surface becomes optically smooth—you can see your reflection.
Figuring
The most delicate phase. Fine-tune the parabola using controlled polishing strokes guided by optical testing.
Coating
Once figured, your mirror is sent out for professional aluminum coating—then it's ready for first light.
Rough grinding a 10" mirror blank
Foucault knife-edge test in action
A freshly coated 8" primary mirror
Our well-equipped mirror grinding workshop
Member-built Dobsonian telescope
Fine polishing with pitch lap