How We Recoat the LDT’s 14-foot Primary Mirror

The massive primary mirror of the Lowell Discovery Telescope (LDT) measures 14 feet in diameter by 4 inches thick. Yet its critical reflective layer is only 100 nanometers thick—1,000 times thinner than typical photocopy paper! This aluminum skin must be periodically replaced, a painstaking process that takes weeks to complete. Tonight, LDT Engineering Manager Frank Cornelius will join Lowell Historian Kevin Schindler to describe the process, sharing dramatic video footage from a recent recoating effort.