As an amateur astronomer I want my primary mirror (diameter 37 cm) to maintain the same temperature as the air. Small fans on the backside do the job. Only, the air cools quicker during the night than the 1.5 cm thick glass. Do I obtain a slightly lower temperature on the backside by sticking something wet (cloth?) on the backside, where the fans blow? And thereby cooling the mirror somewhat quicker. Wet skin, or wet clothes on my skin feels colder when it blows. But does the same principle apply concerning my solid mirror?