Next up in the night sky: A total lunar eclipse

A partial blood moon viewed from Cornwall Park, Auckland in November 2021. Photo / Greg Bowker

Tonight, darkness will slip across the face of the moon before it turns a deep blood red.

The total lunar eclipse will be visible throughout North America in the predawn hours — the farther west, the better — and across Asia, Australia and the rest of the Pacific after sunset. As an extra treat, Uranus will be visible just a finger’s width above the moon, resembling a bright star.

“To me, the most significant thing about a lunar eclipse is that it gives you a sense of three-dimensional geometry that you rarely get in space — one orb passing through the shadow of another,” said Bruce Betts, the chief scientist at the Planetary Society.

Here’s what you need to know about viewing the eclipse.

When and where to watch the eclipse

In New Zealand, the eclipse will begin at 9.02pm tonight — with maximum coverage at 11.59pm — and end at 2.56am tomorrow morning.

Aucklanders and those further north might be out of luck, with cloud and showers forecast. The rest of Aotearoa has a reasonable chance of catching the show, with a mix of sun and cloud.

No matter where you are and which phase of the eclipse is happening, it is safe to watch with your unaided eyes.

What makes a blood moon?

It may come as a surprise that the moon doesn’t simply darken as it enters Earth’s shadow. That’s because moonlight is usually just reflected sunlight. And while most of that sunlight is blocked during a lunar eclipse, some of it wraps around the edges of our planet — the edges that are experiencing sunrise and sunset at that moment. That filters out the shorter, bluer wavelengths and allows only redder, longer wavelengths to hit the moon.

“The romantic way to look at it is that it’s kind of like seeing all the sunsets and sunrises on the Earth at one time,” Betts said.

That outlook is drastically different from those of some of our ancestors. “For many cultures, the disappearance of the moon was seen as a time of danger, chaos,” said Shanil Virani, an astronomer at George Washington University.

The Inca, for example, believed that a jaguar attacked the moon during an eclipse. The Mesopotamians saw it as an assault on their king. In ancient Hindu mythology, a demon swallowed the moon.

But not all lunar eclipses result in the deep red that led to the “blood moon” nickname. Just as the intensity of a sunrise or a sunset can vary from day to day, so can the colours of an eclipse. It’s mostly dependent on particles in our planet’s atmosphere. Wildfire smoke or volcanic dust can deepen the red hues of a sunset, and they can also affect the eclipsed moon’s hue. But if the atmosphere is particularly clear during a lunar eclipse, more light will get through, causing a lighter red moon, perhaps one that is even a ruddy orange.

Among those providing a livestream of Tuesday’s lunar extravaganza: Griffith Observatory in Los Angeles and the Italian-based Virtual Telescope Project.

It’s the second total lunar eclipse this year; the first was in May. The next one won’t be until 2025. Plenty of partial lunar eclipses will be available in the meantime.

This article originally appeared in The New York Times.

- With AP

Written by: Shannon Hall

©2022 THE NEW YORK TIMES