The c4 in the user name is by accident only there seems to be 3 other brianc's on the net and they must all have similar interests to my own! Plain ole brianc is always taken times 3 about every web site I visit!

   As for the temperatures that can be achieved check out Edmund Scientifics web site they offer a 2 foot diameter perfect mirrored parabola that will hold a quarter of an inch focal point & achieve 2,500 deg. F temperature!

   That is a good thought on using the pipe as the pivot point. Very elegant and simple and well worth incorporating into my final design.

   I have my first tracking system designed using some very small but powerfull pv cells driving relays hooked up to dc gearmotors that has proven to work out very well in the prototype stage.

   The first working model should be done next week and will be installed on a dual axis parabolic dish solar cooker.

   I will post pictures of unit in the coming week.

   The great thing about the design is that the relays will handle 7 amps of current at 30vdc so you can drive some big torque dc gearmotors if necessary. From the input side the relays only require 1.2 milliamp current at 12v dc. The small PV cells I am using to drive the relays are epoxy encapsulated and produce 8v at 44 milliamps in full sunlight. They have been very reliable at tripping the relays.