1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can a spy satellite read the house number on your mailbox?

  1. Apr 16, 2013 #1
    If the spy satellite, which is 200km above the earth, uses a concave mirror 2m in diameter and yellow light at 600 nm find the answer. show all formulas and work to support the correct solution. with that resolving power what could the spy satellite actually see? (ignore variations in air density and temperature.)

    The only formulas that I can see as being useful are: thetamin = 1.22*Wavelength/distance (Rayleigh criterion) and 1/focus =1/object+1/image

    Quite frankly I don't think there is enough information to figure this out. Any help would be appreciated.
  2. jcsd
  3. Apr 16, 2013 #2


    User Avatar
    2017 Award

    Staff: Mentor

    "Distance" should be "size of the object" (or, alternatively, size of the mirror).
    You can use that formula to calculate everything in this problem.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted