Kendrick Primary Heater for 6 to 10 inch Newtonian Primary Mirrors

Kendrick Heating for the Primary Mirror of Newtonian and Dobsonian Telescopes

Especially on our humid nights the primary mirror of a telescope can dew. This ends the observation or astrophotography session before it has really begun. Telescopes with an open design are particularly affected.

A primary mirror heater can prevent this. Fogging is prevented by minimal uniform heating of the primary mirror from the rear.

It is sufficient to operate the heater at a low level to avoid tube seeing. 10-20% of the maximum controller setting is usually enough. Only in order to "free" already dewy mirrors, you should go to the maximum level for a few minutes.

Heating the primary mirror is much more effective than ventilation, the essential advantages are:

No additional moist air will be blown into the telescope interior.

With the appropriate control, the dew protection can be optimally set and possibly even controlled via the computer.

Depending on the user´s preference, securing can be done with adhesive tape, glue or silicone caulk. The latter has the advantage that it can be easily peeled off to remove it if necessary, but it holds better than usual adhesive tape.

Safety informations: PDF Download