Solar Angle Calculator

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Placeholder for instructions on Prometheus Calculator

  1. The correct angles are actually given by the Simulator, which run's in Octave and is difficult to use (explanation coming shortly).
  2. The Calculator, which runs in Open Office Calc (spreadsheet) only gives an approximation.

How the angles are set

In the Solar Fire P32 intro video, it's mentioned that the tubes that hold the mirrors are set at the correct angles with a jig, based on values provided by the Solar Fire Simulator.

There wasn't time to make a video of this process, but presented below are the concept drawings. 2D schematics and 3D CAD will follow later in the GVCS - Solar Fire Design campaign.

Solar Fire Mirror Setting

download file


The above animation is not to scale in any way. It is simply to explain the concept with a minimum of components; no nuts and bolts etc.


  1. The first object you see is an empty row.
  2. The second object is the Angle Setting Jig (The Angler).
  3. It's simply a triangle.
  4. The height is fixed, so by modifying the base with the small rod you see, we can control the angle of the Control Rod (the longer rod that swings down).
  5. We then attach the tube to the row and remove the rod.
  6. The tube is now fixed to the row at the chosen angle.
  7. (The angles of all the mirrors are given by the Solar Fire Simulator.)
  1. We can then set the mirror.
  2. We attach the rod-triangle assembly to the back of the mirror (with epoxy).
  3. We pull the rod through the triangle which in turn pull the mirror and causes it to bend.
  4. We bend until we have a good focal point at the correct distance, either on the wall or when placing the mirror and adjusting directly on the target.

The mirror is now bent and set at appropriate angle.

Repeat hundreds of times (depending on size of machine) until all mirrors are set on their rows.

Time Required

For the Solar Fire P-32, there are 36 mirrors per row, so 18 on each half row (shown in the above animation). For demonstration purposes in the above animation we placed the crane, set the base rod, set the tube and the removed the crane. In reality, we start at the exterior tube the move to the next one until all the tubes of the row are set. To set a single tube took us a about 45 seconds when we were working quickly.

So the 360 tubes can be set in 4 and a half hours at that rate, which is acceptable, though there's also the time to set the row on the jig, take breaks, make mistakes from time to time, so double or triple the time should be expected in reality.