Expert: Paul Soderman - 12/21/2008

Question
Hello Paul,

Is there a way I can make a light or heat seeking device to fit onto a telescope?
I'd like it to track the path of the sun automatically, no servo motors, just a seeker locked on and moving the barrel of the telescope.
This might be impossible to make....but I am trying to do away with the motor and replace it with maybe magnets or something that are activated by the moving sun....you see I'm asking for some inventive ideas on how I can create a "mechanical muscle" that is activated by the gradually moving sunlight or sunheat....any ideas?

Thank you.  

Answer
Mike
A passive solar tracker might do the trick.  Here is what Wikipedia has to say:

"use a low boiling point compressed gas fluid that is driven to one side or the other (by solar heat creating gas pressure) to cause the tracker to move in response to an imbalance. As this is a non-precision orientation it is unsuitable for certain types of concentrating photovoltaic collectors but works fine for common PV panel types. These will have viscous dampers to prevent excessive motion in response to wind gusts. Shader/reflectors are used to reflect early morning sunlight to "wake up" the panel and tilt it toward the sun, which can take nearly an hour. The time to do this can be greatly reduced by adding a self-releasing tiedown that positions the panel slightly past the zenith (so that the fluid does not have to overcome gravity) and using the tiedown in the evening. (A slack-pulling spring will prevent release in windy overnight conditions.)

The term "passive tracker" is also used for photovoltaic modules that include a hologram behind stripes of photovoltaic cells. That way, sunlight passes through the transparent part of the module and reflects on the hologram. This allows sunlight to hit the cell from behind, thereby increasing the module's efficiency. Also, the module does not have to move since the hologram always reflects sunlight from the correct angle towards the cells."

Do a google search on solar tracker.
Paul