The Sommers-Bausch Observatory at the University of Colorado at Â鶹¹ÙÍø is hosting an open house — weather permitting — to view a very rare planetary phenomenon on Monday, Nov. 15, from 1:30 p.m. to 3:30 p.m.
Using a heliostat — a specialized solar telescope that transfers the sun’s light via a series of mirrors and lenses and projects it on a flat surface for safe viewing — people will see Mercury’s silhouette gliding along the upper edge of the sun as it passes between Earth and the sun.
Such a "transit" by Mercury happens only when the innermost planet passes directly between the Earth and sun, an event that occurs only 13 times a century and hasnÂ’t been visible here for 26 years, according to Keith Gleason, manager and laboratory coordinator at the Â鶹¹ÙÍø observatory.
"The last two times the phenomenon occurred, the sun had already set, making it impossible to view here in North America," Gleason said.
Mercury will appear as a miniature black dot, about one-one hundred eightieth the diameter of the sun, skimming along the edge of the sun.
"This particular transit is a "grazing" one, with MercuryÂ’s disk just barely crossing the edge of the sun. No one has ever seen a similar event before, since the last time a grazing transit of Mercury occurred was before the invention of the telescope," Gleason said.
Sommers-Bausch Observatory is located just east of Fiske Planetarium on Regent Drive on the CU-Â鶹¹ÙÍø campus. For more information call (303) 492-6732, or visit the homepage at .