Mercury passing in front of the sun. A nice sunspot to the upper left; Mercury is lower right.
Captured on a Meade ETX (90mm scope) using a MacBook Pro, a modified Unibrain Fire-i Firewire webcam and Equinox 5.3 (the newer version doesn't have webcam control). Details on how I modified the webcam are at: http://www.goldbug.com/barry/astronomy/unibrain.html
50 frames aligned, stacked and sharpened using Keith's Image Stacker. Levels tweaked in Photoshop.