For the obvious reasons, I invariably get too busy to blog exactly when things get interesting...
Aim Here.
Reflection Testing
First Light - Panel lit at 100m - Click to zoom in
It's a long walk back up the range
The first thing we do during field testing is look at beam control and reflections, at low power.
The pirates self-sufficient as ever, have their own sponsor-laden calibration target. The calibration process is straight forward – you aim for the center of the cross, and see where the laser hits (and how big the spot is). Adjust, and done.
Calibration is best performed at 1 km, but atmospheric disturbances (hot air shimmering all over the place, and even the mirage effect) make that difficult as the day grows longer. One lesson learned – calibration during the games will have to take place before 8am.)
Once we know the pirates can shoot accurately, we want to look at the reflections the climber generates. For that we use the same U-Haul (A thousand uses and two now, and counting) as a portable darkened room. We locate it away from the laser, with the climber near the back wall, and illuminate it. The reflection are easily visible on the projection screen.
Or are they? We see nothing. Is our equipment mal-functioning?
As it turns out, the Pirates’ climber is almost completely diffusive. There are no direct reflections – whatever light is reflected, it comes out in all directions, and so does not generate any visible spots.
We use a sensitive power meter to look for the reflected light intensity, and only from about 10 m does it register in the mWatt range. (In the games, the climber is always at least 100 m away from the goggled operators, and 1000 m away from anyone else.)
Finally, we want to remove the climber and measure the truck itself, so we can eliminate the background measurement. As we do this, we already realize what is about to happen – the measurement without the climber is actually more reflective… Since the climber is a better diffuser than the truck, it was actually shading it…
In short – KCSP passes these two tests. Next up is full power/duration testing, and tracking testing.