A Quartz Lightweight Blank for a TI35 Astrograph

Holding a 362 mm diameter quartz blank in your hand and having the impression that it is made of plastic … it’s fantastic   –    Fused Silica (Quartz) performs an awesome thermal expansion coefficient of 5.4 x 10-7/℃ , 6 time less than borosilicate glasses, harder enough to allow better figuring process and advantage in terms of strength to density ratio.