Sundials - World's Oldest Clocks

North American Sundial Society

NASA has taken outstanding video of the June 6th 2012 transit of Venus.  Images were recorded by the NASA Solar Dynamics Observatory Satellite that records the sun's surface and corona at a number of visible light and ultraviolet wavelengths. [See]   These images showing the 2012 transit of Venus were recorded at a wavelength of 171 Angstroms (AIA 171) (Extreme Ultraviolet).  This channel is especially good at showing coronal loops - the arcs extending off of the Sun where plasma moves along magnetic field lines. The brightest spots seen here are locations where the magnetic field near the surface is exceptionally strong.  

NASA video source and images may be found at