Caltech: Mercury Transit Public Viewing

Michael Zhang
11 November 2019
Time: 08:00 am until 10:00 am

Come watch Mercury pass in front of the Sun, for the last time until 2032! We will have a SolarScope and 6 telescopes, one with a hydrogen alpha filter and the others with neutral density filters. Under a neutral density filter, Mercury will be a small, completely black dot against the perfectly circular solar disk. Under the hydrogen alpha filter, the Sun's surface is visibly divided into granules--cells of rising and falling gas, carrying the heat from nuclear fusion outwards from the deep interior. Our volunteers are professional astronomers, who will answer any questions you might have about the transit or astronomy in general.


Planetary transits have been crucial to astronomy. In the 18th century, transits of Venus allowed astronomers to measure the size of the solar system. Long before the Space Age, transits of Mercury showed that Mercury had no atmosphere and no moons. In the 2010s, thousands of planets were discovered around other stars by looking for planetary transits. Just as Charles Green studied Mercury's atmosphere through a Mercury transit, modern astronomers now apply similar techniques to study atmospheres of these exotic transiting worlds, millions of times more distant.Parking: the temporary parking lot on Beckman Lawn is reserved for construction workers. Please do not park there. Instead, you can get a visitor parking permit in the parking garage across the street and slightly to the north of Beckman Lawn:


Please check our Facebook event page ( on Nov 11 for weather updates and location changes. RSVP is highly encouraged.

Contact Details:

Michael Zhang


Disabled Access:


Entry Fee:



Beckman Lawn
Pasadena, CA