THE SOUTHWORTH PLANETARIUM
207-780-4249 www.usm.maine.edu/planet
70 Falmouth Street Portland, Maine 04103
43.6667° N 70.2667° W
Altitude: 10 feet below sea level
Founded January 1970
Julian date: 2458778.16
2019-2020: XXXVI
"There are two ways to live: you can live as if nothing is a miracle; you can live as if everything is a miracle." -Albert Einstein
THE DAILY ASTRONOMER
Tuesday, October 22, 2019
Preparing for the Transit
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THE SOUTHWORTH PLANETARIUM WILL BE OPEN
FOR THE TRANSIT OF MERCURY
FOR THE TRANSIT OF MERCURY
Monday, November 11, 2019
Watch this event with us!
Free and open to the public.
Watch this event with us!
Free and open to the public.
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Slightly less than 20 days!
On November 11, 2019, we -weather permitting, schedules allowing- will observe the direct passage of Mercury across the Sun. These events, called "transits," are exceedingly uncommon. (Mercury transits the Sun only 14 times in the 21st century. Venus won't transit the Sun again until December 2117.) While they don't offer the spectacle of solar eclipses or the pop and pizazz of meteor storms, transits remain one of the most intriguing of all celestial events. By watching the passage of a planet across the Sun, not only are we seeing direct evidence of the heliocentric (Sun-centered) solar system model, we are benefitting from the power of mathematical astronomy: its ability to precisely predict cosmic events years, centuries, even millennia in the future.
In short (too late), we'll be watching an entire world traversing our parent star. Although Mercury and Venus have literally crossed the Sun from Earth's perspective millions of times throughout the vast expanse of natural history, we have only known about -and been able to observe- these transits since the early 17th century.*
Let's review the facts:
The transit of Mercury will begin in Portland at 7:36 a.m. Mid transit occurs at 10:20 a.m. and the transit ends at 1:04 p.m. for a transit duration of 5 hours and 28 minutes. The times will vary only slightly in other New England and eastern American locations. Do note that the transit beginning time refers to first contact. Mercury first appears to touch the Sun's edge at 7:36 a.m. The entire planet will be visible against the Sun about 1 - 2 minutes later.
As Mercury is so small and will be 63 million miles from Earth on November 11th, this transit is only observable through a telescope or binoculars. One MUST either use a protective filter covering the end of the optical tube** or must project the Sun onto an opposing surface to allow for safe viewing.
Mercury will appear as a small black dot moving along a path that nearly brings it across the Sun's center. This particularly long trajectory will keep Mercury in sight almost five and a half hours. We'll have plenty to time to observe this transit. One should certainly at least spend a moment watching this transit, as we here in the eastern United States will not be able to see another Mercurian transit until May 7, 2049! (Mercury will transit the Sun twice in the intervening period: in 2032 and 2039. However, neither transit will be visible here.)
On November 11th, the first world will transit the Sun, giving us a rare opportunity to see it during the day. Mercury will then return to the early morning eastern sky in late November, to begin yet another series of oscillations that will swing it from the morning to the evening and back to the morning sky again. Being so close to the Sun, Mercury is the most elusive of all the visible planets. On November 11th, it will literally be front and center in our view. We hope that you can view it with us
*Pierre Gassendi was the first person to observe a transit. He watched a transit of Mercury in 1631.
**Do you have a "protective" eyepiece filter. Do your eyes a favor and toss it into the ocean. Let Davy Jones obliterate his eyes as he tries to observe the Sun through it. The problem with eyepiece filters is its location: at the very focal point of the solar energy. One does NOT want to look through such an eyepiece should the filter fail.
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