Available soon one 18" F/4 fused quartz mirror -Focal length 72 inches. Edge thickness 1-1/4" (31mm)
This glass was supplied by Five Star Optical Supply, then finish machined and precision annealed by ZOC. This mirror has precision ground face and back bevels using our unique ring grinding process for smoothness and uniformity, and a fine grind and 30 hr polish on the back, eliminating any possibility of Twyman effect in this thinner substrate.
Enjoy ultra fast equilibration and ambient tracking combined with a quartz expansion coefficient 1/6 that of borosilicate for consistently stable images limited only by seeing conditions. Especially in large sizes such as this we belive quartz is the "Holy Grail" of telescope mirror substrates.
Our customer cancelled their order so this mirror is available in 60-90 days.
Price includes Zambuto IAD coating, center spot of your choice, packaging and shipment to the lower 48 states (international shipping at cost).
Perfect anneal test (below)