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 uniform bevels using our unique ring grinding process, and a fine grind and 30 hr polish on the back.
Enjoy ultra fast equilibration and ambient tracking combined with a quartz expansion coefficient 1/6 that of Pyrex for consistently stable images limited only by seeing conditions. Especially in large sizes such as this we belive that quartz is the "Holy Grail" of telescope mirror substrates
Customer cancelled order, so this mirror is available for shipment in 60-90 days
50% deposit places order
Perfect anneal test (below)