Asterion Cooler NT8

nozzle for blowing the telescope main mirror

(Synta 200mm)

The problem of thermal stabilization of telescope optics is familiar to many amateur astronomers. The mirror of a reflector telescope, just taken for observation from a warm room or car interior, takes a long time to cool down to the ambient air temperature. A boundary layer of warm air appears above the reflecting surface, and upward currents rise along the tube. All this spoils the picture, especially at high magnification. At a temperature difference of 10-15° the main mirror of a large telescope can cool down for several hours, making it impossible to make quality observations.

The problem is solved by installing active cooling for optics. The Cooler NT8 main mirror frame attachment is equipped with a powerful blower fan. The fan creates a low-pressure zone around the main mirror and, due to this, the air inside the tube starts blowing the front surface of the mirror. This blowing solves three problems at once: it
allows to get rid of convective flows rising along the tube walls, to blow away the layer of warm air bordering the mirror, and to speed up the mirror cooling process.