During the night of January 20-21, 2019, the Moon will move into Earth’s shadow – an event known as a lunar eclipse. From our viewing perspective on PEI, we will see the Moon be completely covered by the darkest part of the Earth’s shadow (the “umbra”) and so we will see a “total” lunar eclipse.
When the Moon is in the darkest part of Earth’s shadow, some sunlight reaches the Moon after travelling through Earth’s atmosphere. The blue light gets scattered by the atmosphere so mostly only the red light reaches the Moon’s surface. This reddish appearance is while a total lunar eclipse is sometimes called a “Blood Moon”. If you’d like to learn more about what happens during a lunar eclipse, watch the video below from RASC or read about why there isn’t a lunar eclipse every full Moon and why the Moon appears red during a lunar eclipse on EarthSky.org.
Lunar eclipses are a slow event and they don’t require any special equipment to view them, so they’re a good opportunity to so some backyard astronomy. Unlike a solar eclipse, a lunar eclipse is completely safe to view with the naked eye. If you have binoculars, you may enjoy using them to look at the Moon’s features more closely, especially at the edge of the Earth’s shadow. If you want to photograph the eclipse, read some tips here. Since this eclipse will be happening in the middle of a January night on PEI, your preparations should include dressing very warmly and perhaps a nap earlier in the day.
The website TimeAndDate.com provides a handy timeline of the eclipse and an animation of what it will look like from Charlottetown. Although the eclipse technically begins at 10:36pm, the first “penumbral” phase is very difficult to see (because the Moon is only in the lighter part of the Earth’s shadow, called the “penumbra”). When the darker part of Earth’s shadow starts moving across the Moon at 11:33pm, it will be easily visible as you’ll see the Moon’s surface grow increasingly dark. By 12:41am, the Moon will be completely in the Earth’s shadow and will appear to have a reddish tint. This “total” phase of the eclipse will last until 1:43am. After that, until 2:50am, you can watch the Earth’s shadow move away from the Moon. So even if it’s partly cloudy on the night of the eclipse, each phase lasts long enough that you could possibly watch the eclipse when there’s clear breaks between clouds. If it’s completely overcast, you can watch the eclipse online (you might want to just pop into the live feed now and then because it’s not a fast, dramatic event). Live feeds will be offered by the Virtual Telescope Project and timeanddate.com, among others.