The cooker needs clear sunlight to work. Under the cooker you should see a clear shadow picture of the whole mirror. There should be no shadow of trees, buildings or persons in the mirror area while cooking. If only part of the mirror catches sunlight the heat is reduced.
Also the pot itself makes shadow on the mirror, which can of cause not be avoided. But smaller pots are making less shadow and therefore slightly collect more energy. Don't use pots of much larger size than really needed. Therefore the Ethiopian Jabenna is ideal while the Ethiopian Mirte-Plate for making injerra of nearly 1 meter diameter should not be used at all.
(But making small diameter Injerra in a black pan with lid of up to 40cm diameter works perfect!)
Place the cooker on level ground, best with no vegetation on it. In about 2 meter distance around the cooker there should be no dry gras on the ground, which might otherwise inflame in a very unlucky combination of conditions.
For conveniance it is nice to have a shade for the cook next to the cooking place, which always has to be in the full sunlight. You may use an umbrella as well but the not both hands are free to operate.
Switching on the heat:
- Move the cooker (turn it) on the ground around the vertical axis until the shadow of the stand-triangles on both sides of the stand are falling exactly on (ore parallel to) the triangle-side placed on the ground.
- Turn the mirror around the horizontal axis until the shadow on the little "solar-clock" (direction indicator) becomes a little point and has no longer a line-shape. Fix this mirror position by connecting the thread from the back of the lower mirror half to the stand. Now the heat concentration in the cooking area is highest! If the cooker is clean and good made even a white sheet of paper should start burning in the cooking zone if there is bright sunshine!
Click on picture to enlage it
The cooker on this picture is good placed and adjusted: Full shadow of the mirror is clearly visible on the ground, the shadow of the vertical parts of the triangles left and right are on/parallel to the horizontal part of the triangles on the ground, the solar indicator makes the smallest possible shadow and the people are behind the mirror not to make shadow on it.
To switch the heat on and off just turn the mirror vertical (off) and back to this position (on). Because the sun is moving during daytime (due to rotation of the earth) the heat is switched off by it self within half an hour. So to keep the heat in the focal zone (cooking zone) on full power all the time, you have to re-adjust the cooker every 10 to 15 minutes in the way discribed above. Like the fire extinguishes if you don't feed it all the time, the solar fire in the cooking zone extinguishes if you don't keep track with the sun.