Refractors, reflectors, magnification, eyepieces, and mounts.
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- What is a refractor telescope?
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A telescope that uses a lens (objective) to collect and focus light.- How does a refractor telescope focus light?
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Light passes through a curved objective lens at the front, which bends (refracts) the light rays to converge at a focal point.- What is chromatic aberration?
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An optical defect where different colors of light focus at slightly different points, causing colored fringes around objects in refractors.- Name one advantage of refractor telescopes.
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Low maintenance, no mirror cleaning or realignment needed.- Refractors excel at observing which type of objects?
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The Moon, planets, and close double stars, due to their sharp and stable images.- What is a reflector telescope?
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A telescope that uses a curved primary mirror to collect and focus light.- How does a reflector telescope focus light?
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Light bounces off a large curved mirror at the bottom and is concentrated to a focal point where an eyepiece is positioned.- Describe a Newtonian reflector's design.
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A parabolic primary mirror at the bottom, a flat secondary mirror angled 45 degrees near the top, and an eyepiece mounted at the side of the tube.- Describe a Cassegrain reflector's design.
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A parabolic primary mirror with a convex secondary mirror that reflects light back through a hole in the primary; eyepiece is behind the primary.- What is a Gregorian reflector?
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An older reflector design with a concave (not convex) secondary mirror that reflects light back through a hole in the primary.- Name one advantage of reflector telescopes.
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They have no chromatic aberration and are simpler and cheaper to manufacture in large apertures than refractors.- What is one disadvantage of reflector telescopes?
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Mirrors require regular cleaning and collimation (realignment) to maintain optical quality.- What is magnification in a telescope?
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The amount by which a telescope enlarges the apparent size of an object.- What is the formula for calculating telescope magnification?
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Magnification equals the focal length of the objective divided by the focal length of the eyepiece.- What is the useful magnification limit for a telescope?
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Approximately 50 times the aperture in inches, or about 2 times the aperture in millimeters.
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