The world’s largest telescope made only from lenses (with no mirrors) is located
ID: 1411469 • Letter: T
Question
The world’s largest telescope made only from lenses (with no mirrors) is located at the Yerkes Observatory near Chicago. Its objective lens is 1.0 m in diameter and has a focal length of +18.9m. The eyepiece has a focal length of +7.5 cm. The objective lens and eyepiece are separated by 18.970 m. a. What is the location of the final image of a Moon crater 3.8 x 105 km from Earth? b. If the crater has a diameter of 2.0 km, what is the size of its final image? c. Determine the angular magnification of the telescope by comparing the angular size of the image as seen through the telescope and the object as seen by the unaided eye.
Explanation / Answer
a )
given
from for eye piece
S0 = 18.970 - 18.90
S0 = 0.070 m
focal length f = + 7.5 cm = 0.075 m
using equation
1 / f = 1 / S0 + 1 / Si
1 / 0.075 = 1 / 0.070 + 1 / Si
1 / Si = 1 / 0.075 - 1 / 0.070
1 / Si = - 0.9523
Si = - 1 / 0.9523
Si = - 1.050 m or - 105 cm
b )
now to find the final size of the image is
= 2000 X 1.05 X 18.9 / 0.07 X 3.8 X 105 X 103
= 39690 / 26600000
= 1.49 X 10-3 m
c )
the angular magnification is
= ( 1.49 X 10-3 / 1.05 ) / ( 2000 / 3.8 X 108 )
= 26961.003
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.