Can You Look at a Lunar Eclipse? How to Safely Watch on January 31

Super Blue Blood Moon Viewing USA
Photo: Scott Eisen/Getty Images

You could be forgiven for thinking that America is suddenly experiencing lots of eclipses, but what will happen in the early hours of January 31 will be nothing like August's total solar eclipse in the U.S.

While that event lasted just a few minutes and had to be viewed mostly through special safety glasses, the total lunar eclipse happening on Wednesday will last for hours, and be completely safe to watch.

It's being billed as a Super Blue Blood Moon Eclipse. A supermoon is when our satellite is slightly closer to Earth than usual in its orbit, which results in a slightly larger and brighter moon — about 14 percent larger. Since the moon is so small in the night sky, that size difference will be difficult to appreciate.

It's the same with a Blue Moon, which is purely a human construct. It has to do with how many full moons there are in one calendar month or astronomical season — and no, the moon won't turn blue. Nor will the eclipsed moon turn blood red, but will instead transforming into ever-changing reddish hues of pink, copper, brown and copper. This is the real majesty of a total lunar eclipse.

Lunar vs Solar Eclipse

Total lunar eclipses and total solar eclipses are the complete opposite of each other, but they are intrinsically linked. Both occur relatively rarely, and only when the Earth, moon and sun lineup.

In a total solar eclipse, the moon moves exactly between Earth and sun as viewed from a very small area of the Earth's surface, which creates a moon shadow. Anyone standing on a shadow will experience totality, as vast swathes of the U.S. did on August 21, 2017. Another total solar eclipse will occur in the U.S. in 2024; they happen roughly once every 18 months somewhere in the world.

A total lunar eclipse, on the other hand, occurs when the Earth is between the sun and the moon. As a full moon passes through the Earth's deepest shadow, sunlight passing through the Earth's atmosphere is projected onto the moon. The physics is similar to the colour of the sun during a sunset. Cue a beautiful reddish, orange or copper-colored moon.

A total solar eclipse can only happen during the day, and a total lunar eclipse can only occur at night. Unlike a total solar eclipse, where only a very tiny strip of the Earth's surface experiences totality, the whole of the night side of Earth can see at least some of the total lunar eclipse. So instead of just a few people taking part in this event, half of planet Earth will be able to see Wednesday's celestial event.

However, solar and lunar eclipses have much in common. The moon orbit is inclined to the Earth's orbit by a few degrees, so it rarely intersects the ecliptic, which is the line that the sun appears to trace in the sky. When its orbit does cross the ecliptic, the moon is in the right place to create one type of eclipse. Consequently, it often causes another type of eclipse exactly two weeks later. That's the case with this total lunar eclipse.

As regular as clockwork, a solar eclipse will occur on February 15, 2018. Sadly, it's only a partial solar eclipse, and it will only be visible in Antarctica and just slightly from the southern tip of South America.

Can you look directly at a lunar eclipse with your eye?

The total lunar eclipse is completely safe to look at with the naked eye. There is absolutely no need to worry about eye safety for this eclipse — it's really nothing like a solar eclipse in that regard. There are various phases to this eclipse, including the partial phase and a total phase, but all of them are safe to view with your eyes.

Do you need special glasses for a lunar eclipse?

You don't need any special glasses to view a total lunar eclipse. From beginning to end, this celestial event is incredibly safe and simple to view. Even better news is that you can use binoculars and telescopes to look at the moon during a total lunar eclipse without having to worry about using special filters.

It's perfectly safe to point a pair of binoculars at the moon during totality, or at any other phase of the eclipse. It's also advisable to do so — the view will be incredible! However, the most useful piece of equipment for watching this total eclipse is probably going to be a dependable alarm clock to make sure you wake up at the right time.

How to photograph a lunar eclipse

Photographing a lunar eclipse is not easy without significant photographic equipment. Since the Moon is such a small target in the night sky, photographing it with anything less than a telephoto zoom lens is incredibly difficult.

So how to capture the lunar eclipse with an iPhone? For a wide-field image that will include a reddish moon, try using the NightCap Camera app for the iPhone and iPad, though you will need to keep your phone completely still on a tripod (or lean it against something solid).

However, easily the best way to capture the lunar eclipse with a phone is through any telescope. If anyone you know has any kind of telescope — even a small child's telescope — ask to use or borrow it.

First, turn the flash off on your phone. Point the telescope at the moon and put your phone's camera over its eyepiece. After some repositioning, and zooming-in slightly, you will get a great close-up of totality on your phone’s screen. Now focus on the reddish moon and take a souvenir image of a rare and beautiful phenomenon — a total lunar eclipse.

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