ASTR 151 1st Edition Lecture 6 Outline of Last Lecture I 1 4 Earth s Orbital Motion II 1 5 Motion of the Moon III 1 6 Measurement of Distance Outline of Current Lecture I 5 1 Optical Telescope II 5 2 Telescope Sizes III 5 3 Images and Detectors IV 5 4 Atmospheric blurring Current Lecture I 5 1 Optical telescope a Optical Telescopes collects visible light and focuses it at one point i Visible light small part if the electromagnetic spectrum energy carried by waves is proportional to waves is proportional to wave frequency inversely proportional to wavelength b Galileo s first telescope was a refracting telescope i He discovered Europa one of Jupiter s moons not Neptune ii His telescope only magnified 3 times c Refracting Telescopes i Refraction change in the direction of a wave association with change of transmission medium ii Refraction lens depends on energy frequency wave lengths of light iii Lenses only iv Long skinny tube v M F o focal length of optical tube F e local length of eye piece vi Chromatic aberration These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute d Reflecting Telescopes i Reflecting mirror depends on the size of the lens ii Most modern telescopes are reflectors 1 Some light is refracted while others are absorbed 2 It depends on the wavelength iii Large lenses work best but they are also heavy and hard to support 1 Needs a smaller lens to use e Types of Reflecting Telescopes i Four types 1 Prime 2 Neurtonian 3 Cassegrain 4 Nasmyth coud e focus II 5 2 Telescope Sizes a Larger Mirror larger amounts of information that can be gathered i Resolving power can distinguish objects when by their sides if telescope is good b Angular Resolution smallest distance between two resolvable objects i Measured in arc seconds arcsec 0 25 wavelength diameter III 5 3 Images and Detectors a Image Acquisition i Subdivided by 2demisional array of pixels picture elements 1 Was used because 1 photon 1 quantum of energy 2 Easy to share ii Computers process and analyze images b Observatories i Usually found in highest elevations and in deserts to avoid atmospheric noise and air IV 5 4 Atmospheric blurring a Atmospheric Blurring i Called seeing point sources out as speckle platters ii Long exposure images b Earth base Telescopes i High altitudes ii Harder to breathe due to less air and water molecules
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