Transit of Venus seen from the telescope of a sidewalk astronomer in Dolores Park (San Francisco)
The large black dot is planet Venus transiting in front of the sun. The smaller spots are sunspots.
View my other photos of the Transit of Venus. This is a rare astronomical event: The next time this will happen is in year 2117.
This was the view through a large Orion mirror telescope. The aberrations (e.g. Venus not completely round) are caused by atmospheric refraction.
The sky looks black through the telescope because of the very dark filter used to attenuate the brightness of the sun.
For more information about the Transit of Venus, read en.wikipedia.org/wiki/Transit_of_Venus.