Homework 7 Telescope (3)

Science 105 Homework #8 Telescope Define the following 1. Magnification – The ratio of the apparent angular size of an object seen through the telescope relative to its apparent angular size seen by the naked eye. 2. Resolution – The ratio of the diameter of the telescope, which is call the aperture, to the wavelength of the light being observed. The ability of the telescope to separate two stars that are very close to each other. 3. Light Collecting power – The ability of the telescope to collect light and reveal fainter object than can be seen without the aid of a telescope. 4. Objective – The mirror or lens which collects the light. 5. Aperture – The diameter of the objective. 6. Reflecting Telescope – Uses a mirror as the main objective. 7. Refracting Telescope – Uses a lens as the main objective. 8. Chromatic Aberration – A lens may focus different colors of light to different positions therefore producing an image which will be slightly blurred with a blue ring of light around it. 9. Spherical Aberration – A distortion in the image produced by a mirror due to a minor defect in the mirror. Answer the following questions. All questions must be answered in full sentences or full credit will not be given. Any question that has math associated with it you must show all work on your answers or full credit will not be given (just giving a number as an answer does not tell me that you know where the number came from). Note: A full sentence completely repeats or restates the question within the answer. 10. The moon has no atmosphere at all, what wavelengths can we observe from on the surface of the moon? - The lack of atmosphere on the moon means that there is no air to scatter or absorb light, unlike on Earth where our atmosphere affects the wavelengths of light that reach the surface. On the moon's surface, you can observe the entire electromagnetic spectrum without any atmospheric interference. This means you can observe wavelengths from radio waves, microwaves, and infrared radiation to visible light, ultraviolet radiation,

X-rays, and gamma rays. All these wavelengths travel through the vacuum of space and can be detected on the moon's surface without distortion. 11. What is the period of a wave that has a frequency of 100 × 10 6 cycles per second? – T= 1 100 x 10 6 seconds T= 10 − 8 seconds - So, the period of the wave is 10 − 8 seconds. 12. Compare the light gathering power of a 10m Keck telescope with that of a 0.6m telescope. – 1. Light Gathering power = (Diameter of Keck) ^2 =(10m) ^2 = 100m^2 2. Light Gathering Power = (Diameter of 0.6m Telescope) ^2 =( 0.6 m) ^2 = 0.36 m^2 - Comparing the two, the Keck telescope has 100 m 2 of light-gathering power, whereas the 0.6m telescope has only 0.36 m 2 Therefore, the Keck telescope has significantly more light-gathering power compared to the 0.6m telescope, making it much more capable of capturing faint and distant celestial objects. 13. What is the resolution of a 25cm telescope? What do two stars that are 1.5” apart look like through this telescope? – = 1.22 x ( 550 x 10 − 9 ) 0.25 = 2.68 x 10 − 6 radians Angular resolution = 2.68 x 10 − 6 x 206265 ≈ 0.553 arcseconds - This means the telescope has an angular resolution of approximately 0.553 arcseconds. If two stars are 1.5 arcseconds apart and you observe them through this telescope, they would be clearly distinguishable. The telescope's resolution (0.553 arcseconds) is smaller than the separation between the stars (1.5 arcseconds), so you would be able to see them as distinct, separate objects. 14. If you build a telescope with a focal length of 1.3m, what eyepiece should you use to obtain a magnification of 100? – 100= 1.3 m F eyepiece F eyepiece = 0.013 m ¿ 1.3 m ¿