Enjoying EarthSky? Subscribe.

258,865 subscribers and counting ...

Partial lunar eclipse on August 7-8

Tonight – August 7, 2017 – just two weeks before the much-anticipated total eclipse of the sun on August 21, the full moon will pass through the northern part of the Earth’s dark umbral shadow, creating a shallow eclipse of the moon visible in Earth’s Eastern Hemisphere.

As with any lunar eclipse, the moon will sweep through the Earth’s shadow from west to east, even as the moon travels across our sky from east to west.

Watch the partial eclipse live online via the Virtual Telescope Project in Rome, Italy.

Photo at top: April 25, 2013 partial lunar eclipse from Sandy S. Palacpec Jr. in Los Baños, Laguna.

The northern part of the Earth’s dark shadow (umbra) clips the southern part of the moon on the night of August 7-8, 2017. The moon goes through the Earth’s shadow from west to east.

Any lunar eclipse can only happen at full moon, when the moon is opposite, or nearly opposite, the sun in Earth’s sky. That’s the only time that it’s possible for the moon to sail through the Earth’s shadow. Of course, to watch this lunar eclipse, you have to be on the night side of our world while the eclipse is taking place.

Why no lunar eclipse at every full moon?

Looking at the worldwide map below, we can see that most of the world’s Eastern Hemisphere will be in a position to watch the eclipse.

This eclipse will be visible during the evening hours after sunset August 7 from the most of Africa and Europe. However, far-western Africa and far-western Europe (United Kingdom, Portugal, Scandinavia) will not see the partial umbral eclipse because the moon won’t rise until after the eclipse ends. As viewed from much of Europe and western Africa, the moon will actually be in eclipse as it rises in the east at sunset August 7.

Worldwide map of where the partial lunar eclipse is visible on the night of August 7-8, 2017. The Americas totally miss out on the partial umbral eclipse. Click here for a more detailed chart.

By way of an example, we give the local eclipse times for Budapest, Hungary (August 7):

Partial umbral eclipse begins: 7:23 p.m. local time
Moonrise: 8:01 p.m. local time
Greatest eclipse: 8:20 p.m. local time
Partial umbral eclipse ends: 9:18 p.m. local time

Source: TimeandDate

Eclipse diagram via EclipseWise.

In eastern Asia, Indonesia, Australia and New Zealand, the partial eclipse will occur in the morning hours before sunrise August 8. As for mid-Asia (India, western China), the eclipse will happen at late night or around midnight August 7-8.

Here are the local times of the eclipse for Tokyo, Japan, and Jaipur, India:

Toyko, Japan (August 8)
Partial umbral eclipse begins: 2:23 a.m. local time
Greatest Eclipse: 3:20 a.m. local time
Partial umbral eclipse ends: 4:18 a.m. local time

Source: TimeandDate

Jaipur, India (August 7-8)
Partial umbral eclipse begins: 10:53 p.m. local time (August 7)
Greatest eclipse: 11:50 p.m. local time (August 7)
Partial umbral eclipse ends: 12:48 a.m. local time (August 8)

Source: TimeandDate

As you can see from the above eclipse times, the partial umbral eclipse lasts for nearly two hours. We give these eclipse times in Universal Time (UTC):

Partial umbral eclipse begins: 17:23 UTC
Greatest eclipse: 18:20 UTC
Partial umbral eclipse ends: 19:18 UTC

You must convert UTC to your local time. Here’s how to do it.

If you’d prefer, you can use these eclipse computers to find out the eclipse times in local time:

TimeandDate

US Naval Observatory

Although most of the Earth’s Western Hemisphere (which includes North and South America) will not see this partial umbral lunar eclipse, the solar eclipse coming up one fortnight (two weeks) later will be visible from a very wide swath of the Western Hemisphere.

The United States in particular will enjoy a ringside seat, as the rather narrow path of totality (roughly 60 miles or 100 km wide) will swing all the way across the continental U.S., from the U.S. West Coast to the U.S. East Coast, during daylight hours on August 21, 2017.

Total solar eclipse on August 21

September 27-28, 2015 moon in partial eclipse, rising in Tucson, Arizona, as captured by BG Boyd Photo.

Bottom line: You have to be on the nighttime side of the world – in this case, in Earth’s Eastern Hemisphere – to witness the partial umbral eclipse of the August 2017 full moon. The southern portion of the full moon will dip into the Earth’s dark umbral shadow for nearly two hours, from 17:23 to 19:18 UTC on August 7, 2017. The Americas will not be in a position to see this event.

Bruce McClure

MORE ARTICLES