Lab Final Review Guide - LAB FINAL REVIEW- ASTR 263 Build a...

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LAB FINAL REVIEW- ASTR 263 Build a Telescope What are the two main types of telescopes and which type was explored the most in lab? --Refracting: use a lens to collect light** We use this. Also called the Galilean telescope. Light is bent as it passed from one medium to another -Reflecting: use a mirror to collect light How do you find the focal length of a lens? What happens to the rays after refracting through lens if the incoming light is not parallel? --The images of objects at infinity (all astronomical objects) fall a distance called the “focal length” behind the lens. The distance of the focus from the lens depends in part on the distance of the object that is being observed. If the light is not parallel, the telescope won’t be focused. (Be able to use this equation) M= Objective focal lengt h eyepeice focal lengt h= f of objf of eye What happens to light rays entering both the 2D (flat) and 3D (tube) telescope? How does an object look when viewed through a telescope, like the one created in lab? What are some other important properties of telescopes besides magnification? Be able to cite examples for each one to be the priority while building a telescope. Understand and be able to describe angular telescope/resolving power and light collecting ability and how each one relates to telescope components. --light gathering and angular resolution --The size of the objective lens determines the quality of the telescope’s light gathering power and angular resolution. The angular resolution (resolving power) by definition measures the ability of the telescope to resolve two light sources that are close together. The solving power is ~ proportional to the radius of the objective lens. Be able to determine what lenses are needed to build a telescope to magnify a given amount. --Objective lens and eye piece lens Distance to the stars
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LAB FINAL REVIEW- ASTR 263 What is the def. of parallax? Be able to draw a diagram indicating the angles involved. How does distance affect the parallax angle? When is parallax a useful technique? --The stars always appear to be fixed in the sky because of parallax. They are so far away, the naked eye can’t detect changes. --The p. of a star is defined to be one-half of the angel through which is moves during a 6 month period. -- One degree is divided into 60 arc-minutes, and each arc-minute is divided into 60 arc-seconds… one arc- second is 1/3600 th of a degree. So, if the p. is one arc-second, the star is one parsec away. --The further a star is, the smaller the p. will be. --P. is .1 arc-seconds, it is 10 parcels away… if it is .01 arc-seconds, it is 100 parsecs away.
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This note was uploaded on 02/17/2011 for the course ASTRONOMY 263 taught by Professor Moffett during the Fall '10 term at Purdue University-West Lafayette.

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Lab Final Review Guide - LAB FINAL REVIEW- ASTR 263 Build a...

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