a reflecting telescope in which the light, passing through a central opening in the primary mirror, is brought into focus a short distance behind it by a secondary mirror.
an astronomical reflecting telescope in which incident light is reflected from a large concave paraboloid mirror onto a smaller convex hyperboloid mirror and then back through a hole in the concave mirror to form the image
Kassel. a city in central Germany. Historical Examples The following year the political disturbances interfered with the opera performances at Cassel, and caused him much annoyance. Famous Violinists of To-day and Yesterday Henry C. Lahee They weren’t interested in Cassel’s undergraduate days, or in Morse’s conquests. The Hour of Battle Robert Sheckley His life at […]
a lemon-yellow color.
a city in central Florida.