Calculating Angular Size of Moon with Telescope

AI Thread Summary
To calculate the angular diameter of the moon using a telescope, the focal lengths of the objective lens and eyepiece are essential, along with the moon's diameter and its distance from Earth. The initial guess for the angular size is 0.36 rad, but confirmation requires showing the calculations. Key considerations include determining the moon's angular diameter without the telescope and calculating the telescope's magnification. Engaging in these calculations will help validate the initial estimate. Accurate results depend on applying the relevant equations correctly.
A B C
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Homework Statement



The moon is observed using a telescope that has an objective lens with a focal length of 3.0 m and an eyepiece with a focal length of 7.5 cm. What is the angular diameter of the moon if the earth-moon distance is 3.85 × 108 m and the diameter of the moon is 3.48 × 106 m?
(a) 0.36 rad (c) 9.0 rad (e) 40 rad
(b) 4.7 rad (d) 22 rad


Homework Equations



0 = ho / do


The Attempt at a Solution



0 : the angular size.
ho: the high of the object
do: the distance of the object
 
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Hello A B C,

What do you think?
 
collinsmark said:
Hello A B C,

What do you think?

I think it's 0.36 rad, but I'm not sure
 
A B C said:
I think it's 0.36 rad, but I'm not sure

Fair enough. :smile: But if you want us to confirm, you'll have to show us your work. :cool:

Let me ask you,
(i) What's the angular diameter of the moon without the telescope?
(ii) What's the telescope's magnification?
(iii) Are you more sure of your answer after finding (i) and (ii)? :wink:
 

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