Photos of the Moon
Maybe a trivial matter for most, but just to show what a 12x optical zoom on a digital camera can do, here a photo of the crescent Moon.
Here the (almost) full Moon, low above the horizon. The edges are a bit fuzzy due to absorption and refraction of light in the dense atmosphere. The kinks on the left are branches obscuring the edge on that side
Setting Moon, low above the horizon, on 20 January 2007, one of the days when I also took photos of Comet McNaught (C/2006 P1)
Photo of the Moon taken in early-morning sunlight with a Canon EOS 1000 D SLR camera, with a focal length of 300 mm
There is also a page on the geometry of a solar eclipse.