Astronomy Specialist



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This dew heater is designed to heat the back of the Newtonian's secondary mirror.

Newtonian telescope have open tube and that can facilitate the condensation of dew on mirrors, especially the secondary. Once the mirrors are fogged up, the telescope is unusable and cannot be dried up easily with paper.  A heater can prevent this problem.

This model is shaped for glued elliptical secondary mirrors, it is flexible and split on one side so it can be easily installed. Gluing can be done with silicone, glue or double-sided adhesive tape (all not included).

This heater works with secondary mirrors with the longer axis of 75mm or larger. The heater warms the mirror slightly above ambient temperature and clears away dew or condensation. Once the mirror is dry, you can leave your power regulator at a low power setting (about 10%) and the mirror will remain dew free. In extreme conditions you can increase the power as needed. These heaters are very efficient at converting electricity to heat and very little power is required.

The orange thermal insulation reduces heat dissipation into the environment.

Wire length 380 mm


RCA plug

Power usage

2 watts max (0.17 A)

Internal hole dimension
50 mm x 71 mm
Outer dimensions 72 mm x 100 mm
Voltage 12 V

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