Mercury Transit 2019: The Messenger Crosses the Sun
Image Credit: This photo of the 2016 transit event shows Mercury as seen with a large 16 inch telescope! Credit: J. A. Blackwell / Phillips Exeter Academy Astronomy Club
 
Did you know that there are two other objects in our skies that have phases like the Moon? They’re the inner planets, found between Earth and the Sun: Mercury and Venus. You can see their phases if you observe them through a telescope. Like our Moon, you can’t see the planets in their “new” phase, unless they are lined up perfectly between us Earthlings and the Sun. In the case of the Moon, this alignment results in a solar eclipse; in the case of Mercury and Venus, this results in a transit, where the small disc of the planet travels across the face of the Sun. Skywatchers are in for a treat this month, as Mercury transits the Sun the morning of November 11!

You may have seen the transit of Venus in 2012; you may have even watched it through eclipse glasses! However, this time you’ll need a solar telescope to see anything, since eclipse glasses will only reveal the Sun’s blank face. Why is that? Mercury is the smallest planet in our solar system, and closer to the Sun (and further away from Earth) during its transit than Venus was in its 2012 transit. This makes Mercury’s disc too small to see without the extra power of a telescope. Make absolutely certain that you view the transit via a telescope equipped with a safe solar filter or projection setup. Do NOT combine binoculars with your eclipse glasses; this will instantly burn a hole through the glasses – and your eyes! While most people don’t have solar telescopes handy, many astronomy clubs do! Look for clubs hosting Mercury transit observing events near you at bit.ly/findnsn (USA) or at bit.ly/awbtransit (worldwide).
 
photo of the Sun with a tiny round dot of Mercury crossing the surface
Photo of the May 9, 2016 transit of Mercury. Mercury is the small dot on the center right. Note how tiny it is, even compared to the small sunspot on the center left. Credit: Dave Huntz / Oklahoma City Astronomy Club

What a fun opportunity to see another planet during the day! This transit is expected to last over five hours. Folks on the East Coast will be able to watch the entre transit, weather permitting, from approximately 7:35 am EST until around approximately 1:04 pm EST. Folks located in the middle of North America to the west coast will see the transit already in progress at sunrise. The transit takes hours, so if your weather is cloudy, don’t despair; there will be plenty of time for skies to clear! You can find timing details and charts via eclipse guru Fred Espenak’s website: bit.ly/mercurytransit2019  You can also join the transit-watching fun via the web on NASA SDO's "almost-live" coverage at https://mercurytransit.gsfc.nasa.gov/2019/

Mercury’s orbit is small and swift, and so its position in our skies quickly changes; that’s why it was named after the fleet-footed messenger god of Roman mythology. In fact, if you have a clear view of the eastern horizon, you’ll be able to catch Mercury again this month! Look for it before dawn during the last week of November, just above the eastern horizon and below red Mars. Wake up early the morning of November 24th to see Mars, the Moon, and Mercury form a loose triangle right before sunrise.

Discover more about Mercury and the rest of our solar system at nasa.gov
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Addtional Skywatching Resources

Plan your skywatching with help from our planner page, featuring daily stargazing tips courtesy EarthSky monthly sky maps, and videos from NASA/JPL. You can even find out how to spot the International Space Station. Both Astronomy and Sky and Telescope magazines offer regular stargazing updates to readers in print and online. Want to join group of folks for a star party? Find clubs and astronomy events near you, and may you have clear skies!
 
Last Updated: November 1, 2019
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