The public is invited to attend a special daytime astronomy event on May 9, 2016, when the planet Mercury passes in front of the sun. Last occurring in 2006, this historic event will be viewable via a 14-inch telescope from 9:00 a.m. – 11:00 a.m. at the Bowen Celestial Observatory atop the Science Forum (building 2400) on Cuesta College’s San Luis Obispo Campus. A special narrow wavelength-band filter mounted on the telescope will make the sun safe for viewing.

“Mercury, the innermost planet, will take nearly seven hours to move across the disk of the sun, and visitors to the Bowen Celestial Observatory will observe the later stages of its transit,” said Cuesta College Astronomy Instructor Dr. Patrick Len. “This transit is special because although Mercury passes between the sun and Earth every 116 days,  its orbit is tilted so the planet will only move across the face of the sun an average of once every 24 ‘pass betweens,’ or about 13 times a century. The next transit of Mercury will occur on November 11, 2019.”  

Sunspots may also be viewable during this time, depending on the current magnetic activity of the sun. If weather prevents direct observation of Mercury’s movement across the sun, a live internet feed of the event from other observatories around the world will be presented. Cuesta College astronomy faculty will be on hand to answer questions.

The Bowen Celestial Observatory was originally installed with a telescope containing an eight-inch diameter reflecting mirror. In 2004, a Cuesta College Foundation Grant was used to replace it with a computer-guided telescope with a 14-inch diameter reflecting mirror, allowing for more precise guiding and greater light-gathering and resolving power in order to track and observe dimmer objects in the sky. 

For more information on the event, please contact Dr. Len at (805) 546-3100, ext. 2693 or