I'm trying to calculate the diffraction limit/angular resolution for the Hubble Space Telescope. I know this can be found using the formula:(adsbygoogle = window.adsbygoogle || []).push({});

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

Where [tex]\lambda[/tex] is the wavelength of the light being observed and [tex]D[/tex] is the diameter of the objective lens (2.5 m on Hubble).

Now since Hubble is able to observe a wade range of wavelenghts from the ultraviolet to the visible to the infrared spectrum I would describe the diffraction limit as an interval depeding on this range of wavelenghts.

However, in all examples I've been able to find, even http://www.nasa.gov/missions/highlights/webcasts/shuttle/sts109/hubble-qa.html" [Broken], the diffraction limit of optical telescopes is calculated using a single wavelength of 500 nm (~cyan). What's the justification for using this particular wavelength for Hubble (and other optical telescopes).

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# The trouble with Hubble

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