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Field of View

  1. Aug 15, 2005 #1
    I was just reading about the Hubble Telescope and I saw something saying that the planetary camera on it had a field of view of 2.5' x 2'.
    I don't actually know anything about astronomy so I was just curious what the field of view is? I found that the ' meant arcminutes, but that doesn' help me really with what the field of view is.

  2. jcsd
  3. Aug 15, 2005 #2


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    well im not an expert on space photography but i know that an arc minute is 1/60 of a degree. space telescopes use arcminutes as units to measure extremely small angles because of the extremely large (relatively speaking) distances from the object they observe. think of it as a unit of distance like a radian of a circle: 2.5' by 2'. do u see it?
  4. Aug 15, 2005 #3
    so is it really just the angular area that the camera can cover?
  5. Aug 15, 2005 #4


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    Science Advisor

    Yes, it is called angular distension. One arc-minute is almost exactly 1 inch at 300 feet. Target shooters would throw away a gun that can't shoot 1" groups at 100 yards.

    In space though, an arc-minute is quite large for some objects, so they are measured in arc-seconds (1/60th of an arc-minute, 1/3600th of a degree). I've seen a lot of double stars with a separation of only about 0.8 arc-seconds (homebuilt scope).
  6. Aug 15, 2005 #5


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    Staff: Mentor

    FYI, the moon is roughly 30' across, while Jupiter is roughly 30" across (variable).
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