THE USM 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
Altitude: 10 feet below sea level
Founded January 1970
Julian date: 2458623.5
"Made from the best stuff off Earth
THE DAILY ASTRONOMER
Monday, May 20, 2019
The Upcoming Mercurian Transit
is immensely important to us because it will be the last transit of Mercury we'll observe here for the next thirty years! Or, to be a little more precise, the next 29.5 years. If you miss the November 11, 2019 transit of Mercury, you won't have another opportunity to observe one here in the eastern United States until May 2049. Now, if you don't mind traveling to other parts of Earth, you could observe a transit in either 2032 or 2039. In fact, if you don't mind traveling to other spots in the solar system, you could see a transit of Mercury right now!*
A transit of Mercury occurs when the planet moves directly in front of the Sun with respect to us. As the previous transit occurred in May 2016, we can hardly complain that we're about to experience a dearth of Mercurian transits.** Moreover, Mercury describes a long path across the Sun during the November 2019 event, providing us with ample time to observe the transit:
Mercury's path across the Sun During the November 11, 2019 transit, Mercury will follow such a long path across the Sun that the planet will remain visible for nearly five and half hours! As we eastern American observers won't observe another transit until May 2049, this event will afford us ample opportunity to see the first world's shadow against Sol.
Throughout the next few months, we'll return to this transit with more detailed information. (We'll also post and distribute a free module, as well.) For now, we'll restrict ourselves to some basic information and questions.
The transit will occur on November 11, 2019.
For we few, we happy few in Portland, the transit will begin 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 be visible against the Sun about 1 - 2 minutes later.
WILL I NEED EYE PROTECTION?
One always needs eye protection to observe the Sun. However, Mercury will appear so small that one will only be able to observe the transit with a telescope equipped with special filters.***
One always needs eye protection to observe the Sun. However, Mercury will appear so small that one will only be able to observe the transit with a telescope equipped with special filters.***
WHAT DO I DO IF I DON'T HAVE A TELESCOPE?
Simple. Weather permitting, the Southworth Planetarium will have at least one telescope available through the entire transit. You can also contact your local astronomy society. As this will be the last transit we eastern Americans will see for three decades, it is very likely that astronomy societies will be organizing events around this transit.
Simple. Weather permitting, the Southworth Planetarium will have at least one telescope available through the entire transit. You can also contact your local astronomy society. As this will be the last transit we eastern Americans will see for three decades, it is very likely that astronomy societies will be organizing events around this transit.
THIRTY YEARS IS A LONG TIME! WILL A TRANSIT OF VENUS HAPPEN ANYTIME SOON?
Even though the next transit of Mercury that we'll see here won't happen until 2049, the next transit of Venus isn't slated to happen until December 11, 2117. In fact, eastern American observers won't actually see that event. They will see the transit of Venus that will happen on December 8, 2125!
WHY SHOULD WE CARE?
I love this question because we astronomy people hear it constantly. Fact is that yes, this event will prove to be utterly unimportant to many good people who are leading rich and joyous lives. We care because physical reality is inherently fantastic and we love to watch worlds in motion in real time.
I must ask, however, if Patriots coach Bill Belichick rode in on a moon beam to address an audience in Portland, would anybody in the congregation ask, 'Why should we care about this? Football is only a game."
[Inquisition: the Southworth Planetarium has changed its address to Central Park West at 79th Street New York, NY 10024.]
*HUH?
I know. It sounds like just another silly statement we tend to write in these articles. A transit occurs when a planet appears to move in front of the Sun. Well, as Mercury is always moving around the Sun, if you position yourself in the right place at any given time, you can observe Mercury moving directly across from the Sun whenever you wish to do so. Transits of Mercury and Venus are rare because, well, Earth has to be in the right place relative to either planet for a transit to occur. If we could zip around the solar system and occupy any point we wanted, we could binge watch planetary transits.
**Presently, 3.5 years is the least amount of time that will elapse between successive transits. It is fortunate that we were able to observe the 2016 event and provided the skies are clear, we'll be able to watch the entire November 2019 event, as well.
***Such protective filters include aluminized mylar shielding that can be placed on the telescope end. If you have an eyepiece with a protective filter, please do me a favor: place it on the ground and take a sledgehammer to it! You see, one should NEVER trust a filter that is placed on the telescope component where the light focuses! Yes, it might work, but if it doesn't, that focused sunlight is going to burn right into your eye! The mylar shielding is much better on at the end of the telescope where the light enters. It is better still to project the sun's image onto a surface so as to avoid irreparable eye damage altogether.