Glossary > Telescopes > Reflector > Secondary mirror heating
Glossary | Telescopes | Reflector | Secondary mirror heating
This heater prevents condensation on a reflecting telescope’s secondary mirror.
Advanced secondary mirror heaters (SMH) not only heat the secondary mirror, but also measure and compare the air and mirror temperatures. As both temperatures equalise, the heater increases the temperature of the mirror slightly. As a result, no condensation settles on the mirror and there is no interference in the light path.