Vshot measurements of distal ii dish concentrators

摘要

The Video Scanning Hartmann Optical Tester (VSHOT) is a laser ray-trace tool for211u001emeasuring the slope error of solar concentrator mirrors. The VSHOT measurements 211u001emade on two, 8.5-m diameter, Distal II dishes represent its first use on a 211u001econcentrator installed and operating in the field. A number of valuable lessons 211u001ewere learned regarding the use of the VSHOT for outdoor testing. The two dishes 211u001ewere found to have overall figure-of-merit RMS slope errors from an ideal 211u001eparabola of 2.99 and 3.18 milliradians. The VSHOT measurements compare well 211u001equalitatively with distant observer photographs made using a colored concentric 211u001ering target.