The most recent results from wet washing the 2016 coating of the 6.5m MMT primary mirror in-situ

By performing mirror washing one to two times per year, we have surpassed the expected life of our coating. The broader and, therefore, more complete picture for our 2016 unprotected aluminum coating will be presented. After years of periodic water, soap, and cotton swab dabbing of the standard aluminum coating at the MMT, on-glass mirrors-coating properties were maintained close to near-fresh coating levels without detectable scratching of the bare aluminum surface. Data will be shared about the life of the 2016 coating using our Konica Minolta Spectrophotometer CM-600d.