Ready for Tonight’s Total Lunar Eclipse?

On the night of September 27–28, the full Moon will slide completely through Earth's shadow for the last time until January 2018.

Watch the eclipse live! Our exclusive webcast begins Sunday night, September 27th, at 9:00 p.m. Eastern Daylight Time (1:00 Universal Time on the 28th). Watch our streaming high-definition coverage as the Moon glides into and out of Earth's deep umbral shadow, and hear commentary by lunar experts!
Who will see this month's total lunar eclipse?

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.
S&T diagram

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.

Observers in the eastern half of North America can watch every stage of the eclipse, from beginning to end of the partial phases (313 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.


FREE Download: Sign Up Today for a Free eBook on September's Lunar Eclipse!

Prepare for September's total lunar eclipse with our free ebook. In an article reprinted from the September issue of Sky & Telescope, you'll get the exact times for each stage of the eclipse, learn what to look for as Earth's shadow passes over the Moon, and find out why the Moon turns red at totality. Plus, learn your way around the Moon (eclipsed or not) with a bonus Moon map, which includes almost 300 labeled craters and other lunar features.


Along with the free lunar eclipse ebook, you'll also receive our weekly e-newsletter alerting you to news in the world of astronomy.


Total lunar eclipse on Sept. 27-28, 2015

During the upcoming total lunar eclipse, the Moon will take about 3.3 hours to cross Earth's umbra.
Sky & Telescope diagram

Unlike the lunar eclipse last 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 a big eclipsed Moon! 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. That's not enough for anyone but a devoted Moon watcher to really notice, but for a spectacle like a lunar eclipse, every little bit helps.

See the diagram above for key times during the eclipse, given in Universal Time (GMT). Here's the schedule for the main time zones in North America:

Key Times for Total Lunar Eclipse, Sept. 27–28, 2015
Eclipse event UT (GMT)
EDT CDT MDT PDT
Penumbra first visible? 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 02:47 10:47 p.m. 9:47 p.m. 8:47 p.m. 7:47 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 a.m. 11:27 p.m. 10:27 p.m. 9:27 p.m.
Penumbra last visible? 04:55 12:55 a.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 month's total lunar eclipse, with its wide visibility, convenient evening schedule, and record size, is going to get a lot of publicity. In fact, no matter where you are in the world — or if your sky is cloudy! — you can watch the slow progression of this dramatic celestial event via Sky & Telescope's real-time webcast.

 

15 thoughts on “Ready for Tonight’s Total Lunar Eclipse?

    1. Joe StieberJoe Stieber

      I suppose it’s an esoteric point, but I think mid-eclipse should should be listed as 2:47 UT rather than 2:48. The latter actually appears to be TD as shown at the top of NASA’s summary page for the eclipse at http://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2015Sep28T.pdf. There it states that “Greatest Eclipse = 02:48:16.8 TD (= 02:47:07.5 UT).” The difference between TD and UT is Delta-T, 69.3 seconds for the NASA summary. The United States Naval Observatory’s MICA software has maximum eclipse at 02:47.2 UT, using a Delta-T of 67.2 seconds.

      1. Dylan347Dylan347

        You need to send this to Neil Degrasse Tyson and get your geek card stamped and signed. Impressive work. (I intend that to be taken most kind-heartedly) Keep looking up my friend!

      2. Frank-ReedNavigation.comFrank-ReedNavigation.com

        Apparently the table has been fixed?? It lists 2:47 UT as mid-eclipse now. Good catch if they previously copied down the TD time since, of course, clocks don’t often display dynamical time! A one-minute difference is right at the limit of significance for lunar eclipses, but as our great “chronometer in the sky” it’s still important to get it right…

        Speaking of time, for anyone in the northeast USA this fall and winter, John Harrison’s famous chronometer (case and face minus the works) H4 is on display at Mystic Seaport along with many other remarkable timepieces and instruments related to time. It’s a travelling exhibit from the National Maritime Museum, Greenwich, UK. Really impressive! And I myself will be teaching various classes and workshops related to time and celestial navigation there this fall.

  1. rocksnstarsrocksnstars

    Very disappointed to see you supporting the myth of the super moon, even though indirectly. There was an excellent article here about a year ago explaining why the difference in size of any full moon is not discernible. And here is why I agree. If you “measure the moon” by holding a ruler 12 inches from your eye (comfortable reading distance), you will see that 30 arc minutes “measures” 0.1 inches (12 times the tan of 0.025 deg times 2). 13% of 0.1 is 0.013, so this moon will measure 0.013 inches. I know I can’t see the difference of only a little over 1/100th of an inch. Even if it was 25% larger it would measure only 1/40th of an inch larger, which might be detectable, but not without the other moon there to compare it to. 50% larger would make it 1/20th inch larger and of course 100% would double it to 1/10 larger, making it 0.2 inches on the ruler. That I could see! This of course applies to naked eye viewing, which I’m assuming most people will be doing.

    1. davidrandall

      Your math is correct, but you’re conclusion is a little off. True the “supermoon” hype is greatly exaggerated, but the apparent difference in size is in fact very noticeable. The absolute measurement of size viewed at a certain distance is only pertinent relative to the resolving power of the eye, which for an average person is about 1 arc minute. Thus the difference is well within the ability of the naked eye to see. However, when it comes to “noticing a difference” the eye/brain works based on proportion, not absolute differences. Imagine a beach ball that is 1/40″ larger than another. Even side-by-side you might not notice the difference. If it were a baseball you might not notice it without a normal ball to compare it too, but possibly you might if you were a pitcher and very familiar with a regulation ball. If on the other hand, the object were a BB you immediately notice a huge difference even at a quick glance from a few feet away, because proportionally it would be almost twice as big. Now, 13% is not a huge proportional difference, but definitely noticeable even to a fairly casual observer.

      1. Pyrolon

        You have a good point, after all “supermoon” is the only phenomenon invented by astrologers that is now main stream with popular astronomy. I do notice the difference though. It is a lot harder for me to frame a supermoon using my equipment setup than a normal moon.

      2. Frank-ReedNavigation.comFrank-ReedNavigation.com

        David Randall wrote: “Now, 13% is not a huge proportional difference, but definitely noticeable even to a fairly casual observer.” That is pure nonsense. You’ve been taken in by supermoon mania. The simplest evidence that this is not “definitely noticeable” is historical. The word “supermoon” entered the language less than five years ago thanks to a coincidence. The frequently sensationalist web site space.com ran an article about some wacko astrologer who predicted earthquakes at various instances of Full Moon perigee –something which he alone called “supermoon”. And if you keep making the same pseuod-science prediction over and over, eventually, of course, you will get a hit (or at least a near miss). A few days later (NOT at the time of his prediction) occurred the massive, tragic earthquake and tsunami in Japan. Social media went nuts over this with idiots everywhere claiming that the earthquake was caused by the “supermoon”. Suddenly the word has its own Wikipedia page. After that the word became fodder for every fool who needed hits for a web page. But here’s the thing… before this social media mania, no one ever talked about how big the Moon looks visually at perigee. And the simple reason for that is that it is indeed un-noticeable unless it is carefully measured. The supermoon is not an astronomical phenomenon; it is a social media phenomenon.

        Don’t believe it’s only four years old? Here’s an image of Google Trends data

        Frank Reed
        ReedNavigation.com

        1. Pyrolon

          Very true. When “they” (the media) said the last “supermoon” lunar eclipse was in 1982, I was thinking not really since no one was talking about supermoon back then. I knew it was from an astrologer, I didn’t really know the exact context which you elucidate very nicely.

    2. TacMedic

      Just because you can’t see it doesn’t mean it is a myth.

      In fact you spend most of your article talking about measurements of it and proving it does exist. Perhaps look up what myth means. “I do not think that means what you think it means.”

    3. Chris-Anderson

      Funny–I was going to compliment S&T for not jumping on the “super/blood” moon hype bandwagon. I thought they did a nice job of downplaying that aspect.

    4. Frank-ReedNavigation.comFrank-ReedNavigation.com

      I don’t think they’re “supporting the myth of the super moon” here. If they didn’t mention ANYTHING about lunar perigee, the article might have seemed incomplete. They didn’t call it a supermoon, and they didn’t sensationalize the issue. What more could you want? Honestly, it’s a real shame that you’re picking on this article’s excellent description of the issue.

  2. kodiak

    2 questions.
    In the image on this page showing the moon eclipse stages, it shows the moon moving from west to east. (arrow pointer) In my world the moon rises in the east and sets in the west. I am only a casual observer anymore but this is confusing to me.

    If there have been 4 total eclipses in half a year, how could the first one happen in early 2014. This looks like a typo but maybe I am missing something. As the time length of 4 eclipses beginning in 2014 would be 18 months.

    Thanks in advance
    Kodiak

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