Re: Private Universe and the Seasons

[Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU>]

Hugh Haskell wrote:
> Doesn't the size of the spot from a pinhole camera depend on how far
> away from the aperture you place the receiver? I would guess that the
> clearest image would occur somewhere near the point where the
> "umbral" rays cross. If you take the image size at that point to be
> the diameter of the penumbra, it will necessarily be larger than the
> aperture in the case where the rays are slightly converging, as they
> are from the sun.

The pinhole spot, as well as the image from any lens used, subtends 1/2
degree, same as the sun itself. As you get further from the pinhole, or
use a longer focal length lens, the image gets larger, but still
subtends 1/2 degree.

Bob at PC