KELSEYVILLE, Calif. – On Veterans Day, Monday, Nov. 11, there’s a semi-rare and very special astronomical event: Mercury transits the sun.

The last transit was May 16, 2016, but the next one visible in Lake County will be in May of 2049, 29 and a half years from now. Don’t miss this Mercury transit!

Because of the small size of Mercury, direct observations, for example through glasses used for solar eclipses, are not possible. Never use binoculars with the solar eclipse glasses, as serious eye damage will occur.

Monday’s transit is an early morning event. Taylor will open at 7:30 a.m. and remain open until after the end of the transit at 10:02 a.m. Pacific Time.

To enhance your Taylor visit coffee and pastries will be available for purchase from Katy and Sean of Konocti Coffee.

There is no admission charge to Taylor for the Mercury transit, but donations toward Lake County STEM education are always greatly appreciated.

A Mercury transit occurs when Mercury and Earth align exactly on the same side of the sun.

Given that Mercury’s year is just 88 earth days, why don’t we see these transits more frequently?

On most passes between Earth and the sun, Mercury and Earth are not aligned, but an additional complication is that Mercury’s orbit is inclined 7 degrees to the orbit of earth.

Mercury transits occur in groups of six. Monday’s transit is the fifth of the current series, which began in 1999, but the final transit of this series will not be visible in the U.S. Transits of our other inner planet, Venus, are extremely rare.

The most recent one, observed from Taylor, was in June of 2012 but the next transit of Venus is in December, 2117, 98 years from now.

Some caveats:

1. Never look directly at the sun, even for an instant, through binoculars or a telescope that are not equipped with special solar filters.

2. The Mercury transit cannot be observed without telescopic magnification – the disk of Mercury is only 1 percent of the sun’s diameter when observed from Earth. Taylor Observatory will provide three to five safe telescopes for viewing the transits and experienced personnel will be at Taylor to guide your observations.

3. Observations through telescopes will begin at Taylor around 7:45 a.m. when the sun rises over Mt. Konocti. For this event we’ve added a custom-made Baader solar filter to the historic Optical Craftsman telescope used in the observatory by Evelyn Norton in the 1970s and 80s. This telescope has been restored to operation by David Firebaugh and Tom Schleif, and is the new go-to scope for planetary observations at Taylor.

4. Starting at the 7:30 a.m. opening, a video display of the transit from the Solar Dynamics Observatory, or SDO, will be available for viewing in the classroom. Our September Window to the Universe Speaker, Prof. Phil Scherrer of Stanford may be there to explain the live feed from equipment designed by his solar research group and residing on the SDO.

5. Nov. 11 is a school holiday. Parents should consider bringing their children to see this rare event. If skies are overcast, the views of Mercury from the Solar Dynamics Observatory will be available.

Taylor Observatory, located at 725 Oak Hills Lane in Kelseyville, is operated by the Lake County Office of Education for the benefit of Lake County’s K-12 Students. Friends of Taylor Observatory sponsors special events such as this Mercury Transit.

Questions? Call Taylor Observatory at 707-262-4121.

Bill Haddon is president of the Friends of Taylor Observatory.