Mathematically, students wrote the equations of a parabola to find the relationship between the diameter, D, the depth, d, and the focal distance, F, of the dish and found that: Parabolic mirror: focusing on science, technology, engineering, and math The 20mm focal distance, which is said ...
Remarkably, the 2.5 is actuallybrighterin the central 0.6-inch illuminated diameter (less obstruction compared to the 3.1). The 3-inch does better at the edge of the field (down about 0.17 magnitude) while the 2.5 is down about .37 (still acceptable for visual use). #12 lightsky Vostok ...
A three-element test system consisting of a parabola, a transmission sphere, and a folding flat is described. It is capable of measuring both optical flats and convex or concave mirrors up to 40 cm in diameter with radii of curvature from 10 m to infinity. System accuracy is 1/20th wave...