Using Rayleigh's criterion, calculate the diameter of an earth-based telescope that gives this resolution with 700 nm light.

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Complete Question

Due to blurring caused by atmospheric distortion, the best resolution that can be obtained by a normal, earth-based, visible-light telescope is about 0.3 arcsecond (there are 60 arcminutes in a degree and 60 arcseconds in an arcminute).Using Rayleigh's criterion, calculate the diameter of an earth-based telescope that gives this resolution with 700 nm light

Answer:

The diameter is  [tex]D = 0.59 \ m[/tex]    

Explanation:

From the question we are told that

      The best resolution is  [tex]\theta = 0.3 \ arcsecond[/tex]

       The  wavelength is  [tex]\lambda = 700 \ nm = 700 *10^{-9 } \ m[/tex]

       

Generally the

         1 arcminute  = >  60 arcseconds

=>      x arcminute =>   0.3 arcsecond

So

       [tex]x = \frac{0.3}{60 }[/tex]

=>    [tex]x = 0.005 \ arcminutes[/tex]

Now

         60 arcminutes  =>  1 degree

          0.005 arcminutes = >  z degrees  

=>       [tex]z = \frac{0.005}{60 }[/tex]

=>      [tex]z = 8.333 *10^{-5} \ degree[/tex]

Converting to radian  

           [tex]\theta = z = 8.333 *10^{-5} * 0.01745 = 1.454 *10^{-6} \ radian[/tex]

Generally the resolution is mathematically represented as

            [tex]\theta = \frac{1.22 * \lambda }{ D}[/tex]

=>    [tex]D = \frac{1.22 * \lambda }{\theta }[/tex]

=>     [tex]D = \frac{1.22 * 700 *10^{-9} }{ 1.454 *10^{-6} }[/tex]    

=>     [tex]D = 0.59 \ m[/tex]