Astronomy: Types of Telescopes and Accessories, Study notes of Physics

Download Astronomy: Types of Telescopes and Accessories and more Study notes Physics in PDF only on Docsity! Telescopes come in three basic styles Refracting Refracting telescopes use lenses Refractors are either achromatic (some color distortion) or apochromatic (very little if any color distortion). Apo refractors use two or three lenses of high quality material to correct for chromatic aberration APSU has two types of reflectors The Orion 8” Dobs is a Newtonian telescope on an alt-az mount The 8” Ritchey-Chretien Cassegrain telescopes on Orion Atlas mounts are the workhorse of the department Catadioptric telescopes use mirrors and “lenses” Schmidt-Cassegrain Maksutov-Cassegrain APSU has two Meade LX-200 Schmidt- Cassegrain telescopes that are currently not used There are two general types of telescope mounts The Alt-Az mount moves in altitude (height above the horizon) and azimuth (angle around the horizon) The Equatorial mount moves parallel to and perpendicular to the celestial equator One accessory that every telescope needs are eyepieces Since the magnification depends on the focal length of the eyepiece, you want to have three or four eyepieces. Eyepieces come in a variety of different optical designs The differences will improve the color characteristics (no color distortion), give good eye relief (how close does your eye have to be) and apparent field of view (how exact does your eye have to be lined up to see anything). Finder Scopes are another useful accessory Straight finders flip things upside-down. Right-angle finders give a “correct” view. Telrads and EZ Finders have no magnification. Star maps come in all sizes with different levels of details You can find the entire sky in a single map or an atlas of maps to cover the sky. There are also maps of the moon with varying levels of detail. There are map books that show where the most interesting things to look at are The Messier objects are 110 celestial objects like galaxies, nebulae and clusters that were catalogued by Charles Messier in the late 1700’s and early 1800’s There are also lots of apps for phones that guide you around the sky If you want to capture the view you can use a camera You can get adapters that allow you to use a telescope as a telephoto lens for your SLR camera. You also need a remote shutter release for the camera to avoid shaking the telescope when you push the shutter button. Other devices allow you to take a picture through the eyepiece There are also adaptors to hold your phone for imaging The highest quality astronomical images are made with a CCD The CCD takes black & white images so color filters (red-green-blue) must be used to produce a color image. The sensitivity is much higher than a digital camera and the resolution is usually better, too. Finally, you don’t want to use a regular white-light flashlight You can buy flashlights that use red LED’s or you can put red cellophane or a red filter over a regular flashlight. You don’t want to use white light because it will cause you to loose your dark adaptation making things more difficult to see.