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Homework Help: Surface Brightness at any angle

  1. Sep 24, 2016 #1
    1. The problem statement, all variables and given/known data
    Here is a picture of the problem
    For those who don't want to click the link, basically the problem wants me to calculate the surface brightness of a flat surface at any angle if the source function S = B(T), which is a constant.

    It then wants me to consider limits at optical depths τ<<1 and τ >>1, and to know why brightness is not infinite at θ = π/2,

    2. Relevant equations
    Non were provided. My guess for the first part is that I should use something similar to
    F=∫ I⋅Cos(θ) dΩ. I have no idea for the second part.

    3. The attempt at a solution
    I found that for a flat source Ω=2π, so the result of this integral may be F= I⋅2π⋅Cos(θ), however, then the
    second question makes no sense, as Cos(π/2)=0 (unless that's the point). Further, I don't know if that is even the right equation, as I am not sure I want flux for this.

    I am also unsure how to handle the optical depth portion of the question.
  2. jcsd
  3. Sep 24, 2016 #2


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    You may get more response if that image is posted directly.

  4. Sep 24, 2016 #3
    You may get more response if that image is posted directly.

    Thank you! I was unable to do so, I apologize.
  5. Sep 26, 2016 #4
    I'm going to bump this question one more time. I can literally find nothing about this problem online, or in two different text books.
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