A “witness sample” from the moment in the early 1980s when the Hubble mirror was vacuum electrocoated with a reflective layer of aluminum and overcoated with a protective layer of transparent magnesium fluoride.
A “witness sample” from the moment in the early 1980s when the Hubble mirror was vacuum electrocoated with a reflective layer of aluminum and overcoated with a protective layer of transparent magnesium fluoride.