Quote:
On 2001-11-15 08:06, Donnie B. wrote:
Sure they do. The calculations were based on the dimmest visible star being 6th magnitude. I doubt that such a dim star is visible on the fovea. Thus, the resulting photons/sec number would not apply to central vision.
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Well, they still apply--but the receptors just don't respond to that number of photons, perhaps. When the original post asked about the dimmest visible stars, the usual assumption was made that the OP was talking about sixth magnitude stars--but that is a very common assumption. Once that assumption is made, the numbers don't depend upon whether we're using rods or cones.
Around here, we're sometimes lucky to see third magnitude stars. [img]/phpBB/images/smiles/icon_frown.gif[/img]