The optical achromatic refractor is formed from two substantially different curvature and lens material (using the flint glass and Crown, having different refractive index), the reason the use of this optical combination is the necessity of killing the secondary spectrum. It 'a known fact that a single lens focuser at different distances to the blue and red wavelengths, this phenomenon is greatly reduced with the use of an achromatic lens, almost to disappear entirely if the aperture ratio equal to or greater af/15 (ie the ratio between the diameter of the main lens and its focal length is proportional to the power of magnifying lens). Along the optical path are distributed on the inner wall of the tube a series of diaphragms razor blade, in order to increase the contrast of images.
such telescopes are great for observations of all objects in the Solar System (Sun, Moon, Planets) and for the separation of double stars.
are much penalized by footprint, low opening (the cost of achromatic lenses are very high quality) and the aperture ratio which precludes very thorough picture of extended objects.
such telescopes are great for observations of all objects in the Solar System (Sun, Moon, Planets) and for the separation of double stars.
are much penalized by footprint, low opening (the cost of achromatic lenses are very high quality) and the aperture ratio which precludes very thorough picture of extended objects.
also visit fables-and-filastrocche.blogspot.com 
0 comments:
Post a Comment