The view through a porthole of the Gemini South coating chamber

The view through a porthole of the Gemini South coating chamber as the magnetrons apply four extremely thin (about 1/1000 the thickness a typical human hair) layers of adhesive, silver, another layer of adhesive, and finally a silica sealant. This image was taken during the application of the silver layer. Read more at https://www.gemini.edu/node/11532.