On the night of September 27–28, the full Moon will plunge completely through Earth's shadow for the last time until January 2018.
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| This map shows locations from which this month's total lunar eclipse is visible. The timing favors the Americas — especially the eastern parts — and western Europe and Africa. |
If your skies are clear after the Sun sets on Sunday, September 27th, be sure to head outside to see the total lunar eclipse that happens that night. This will mark the end of a "tetrad" of four total lunar eclipses spaced a half year apart that began back in early 2014. But, perhaps more importantly, it's the last one visible anywhere until 2018.
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| During the upcoming total lunar eclipse, the Moon will take about 3.3 hours to cross Earth's umbra. - |
Observers in the eastern half of North America can watch every stage of the eclipse, from beginning to end of the partial phases (31⁄3 hours in all) during convenient hours of late twilight or darkness with the Moon mostly high in the sky. If you're in the Far West, the first partial stage of the eclipse is already in progress when the Moon rises (due east) around the time of sunset. Those in Europe and Africa see the eclipse on the local morning of the 28th.
Unlike the lunar eclipse on April 4th, which might not even have been precisely total, this one will carry the Moon through the umbra — the dark core of Earth's shadow — for 1 hour and 12 minutes. Moreover, it's the biggest eclipsed Moon you'll ever see! That's because the closest lunar perigee of 2015 occurs just 59 minutes before mid-eclipse. The Moon (in Pisces) will appear 13% larger in diameter than it did when eclipsed last April.
See the diagram above for key times during the eclipse. These occur simultaneously for everyone who can see the Moon, but the event times vary depending on your time zone. So refer to the table below for the times that are correct for you:
| Key Times for Total Lunar Eclipse, Sept. 27-28, 2015 | |||||
| Eclipse Event | UT | EDT | CDT | MDT | PDT |
| Penumbra First Seen | 00:40 | 8:40 p.m. | 7:40 p.m. | -- | -- |
| Partial Eclipse Begins | 01:07 | 9:07 p.m. | 8:07 p.m. | 7:07 p.m. | -- |
| Total Eclipse Begins | 02:11 | 10:11 p.m. | 9:11 p.m. | 8:11 p.m. | 7:11 p.m. |
| Mid-Eclipse | 02:48 | 10:48 p.m. | 9:48 p.m. | 8:48 p.m. | 7:48 p.m. |
| Total Eclipse Ends | 03:23 | 11:23 p.m. | 10:23 p.m. | 9:23 p.m. | 8:23 p.m. |
| Partial Eclipse Ends | 04:27 | 12:27 p.m. | 11:27 p.m. | 10:27 p.m. | 9:27 p.m. |
| Penumbra Last Seen | 04:45 | 12:55 p.m. | 11:55 p.m. | 10:55 p.m. | 9:55 p.m. |
The events that happen to a shadowed Moon are more complex and interesting than many people realize. For example, you can look for the first vestiges of shading on the Moon's southeastern side (at lower left if seen from the U.S.) about 30 to 45 minutes before the lunar disk begins its dip into the umbra. This duskiness intensifies as the Moon slides deeper into Earth's penumbra. An astronaut standing on the Moon would see Earth covering only part of the Sun's face.
This event is geometrically special: it features the biggest eclipsed Moon you'll ever see. The closest lunar perigee of the year occurs just 59 minutes before the mid-eclipse mark of 10:47 p.m. EDT. That means the Moon's disk will have an apparent diameter 13% larger than it had during the last eclipse back in April.
Here is a great video primer outlining how and why the eclipse looks the way it does.
Remember: If you miss this event, you won't get another chance to see a total lunar eclipse until January 2018!
Read more: skyandtelescope.com