Publications Details
VSHOT Measurements of Distal II Dish Concentrators
The Video Scanning Hartmann Optical Tester (VSHOT) is a laser ray-trace tool for measuring the slope error of solar concentrator mirrors. The VSHOT measurements made on two, 8.5-m diameter, Distal II dishes represent its first use on a concentrator installed and operating in the field. A number of valuable lessons were learned regarding the use of the VSHOT for outdoor testing. The two dishes were found to have overall figure-of-merit RMS slope errors from an ideal parabola of 2.99 and 3.18 milliradians. The VSHOT measurements compare well qualitatively with distant observer photographs made using a colored concentric ring target.