(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The Lick Observatory has one of the largest refracting telescopes, with an aperture diameter of 36 in. and a focal length of 56 ft. Determine the radii of the first, second, and third bright rings surrounding the Airy disc in the diffraction pattern formed by a star on the focal plane of the objective.

2. Relevant equations

[tex]\frac{\pi}{\lambda}Dsin\theta=\gamma[/tex]

Where \gamma is either the maxima (bright fringes) or minima (dark fringes) of the bessel function which occurs in the solution to the diffraction through a circular aperture.

[tex]r=f \theta[/tex]

Where f is the focal length.

Maxima of Gamma function: 5.136,8.417,...

3. The attempt at a solution

This is not an attempt, this is part of the actual solution. I do not understand a certain aspect of it though.

So using the first equation above and solved for sine. I came into a problem though. The problem doesn't give the wavelength! The solution just says..

"Thus for wavelength of 550nm..."

And then they plug it in. Where did this come from?!

Thanks :D

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# Homework Help: Confused about this Optics problems Solution

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