Introduction

A total eclipse of the Moon occurs during the night of September 27-28, 2015. Observers throughout the Americas and Europe will have a front row seat as the Moon slowly glides though Earth's shadow.

The eclipse will be seen in its entirety from eastern North America, South America, the Atlantic Ocean, western Europe and western Africa. From western North America, early eclipse phases occur before moonrise. Similarly, observers in Eastern Europe, the Middle East and East Africa will experience moonset during some phase of the eclipse. None of the eclipse is visible from eastern Asia, Japan, Australia or New Zealand.

During a total lunar eclipse, the Moon's disk can take on a dramatically colorful appearance from bright orange to blood red and more rarely dark brown to very dark gray. One of the wonderful things about lunar eclipses is that they are completely safe to view with the naked eye. No special filters are required to protect your eyes like those used for solar eclipses. You don't need a telescope to watch the eclipse, although a good pair of binoculars will enhance your experience.

An eclipse of the Moon can only take place at Full Moon, and only if the Moon passes through some portion of Earth's shadow. The shadow is actually composed of two cone-shaped parts, one nested inside the other. The outer shadow or penumbra is a zone where Earth blocks some (but not all) of the Sun's rays. In contrast, the inner shadow or umbra is a region where Earth blocks all direct sunlight from reaching the Moon.

During a total eclipse, the Moon passes completely inside Earth's umbral shadow. If only part of the Moon passes through the umbra, a partial lunar eclipse is seen. It is also possible to have an eclipse where the Moon only passes through the penumbra. Each of these three eclipses types has a unique appearance (see Visual Appearance of Lunar Eclipses). For more information on the how, what, why, when and where of lunar eclipses, see the special web page Lunar Eclipses for Beginners.

A complete report on all eclipses occurring over the year can be found at Eclipses During 2015.

Path of the Moon through Earth's umbral and penumbral shadows
during the Total Lunar Eclipse of September 27-28, 2015.
This version of the diagram gives times in Eastern Daylight Time.
(click for larger diagram)

Lunar Eclipse Diagrams

The diagram above shows the Moon's path through Earth's umbral and penumbral shadows during the total lunar eclipse on on the night of September 27-28, 2015. The times (in Eastern Daylight Time) mark the major phases of the eclipse.

The links below are for diagrams of the eclipse for other time zones throughout North America. Please choose the diagram for your own time zone.

• Eclipse Diagram for GMT (Greenwich Mean Time)
• Eclipse Diagram for EDT (Eastern Daylight Time)
• Eclipse Diagram for CDT (Central Daylight Time)
• Eclipse Diagram for MDT (Mountain Daylight Time)
• Eclipse Diagram for PDT (Pacific Daylight Time)
• Eclipse Diagram for AKDT (Alaska Daylight Time)
• Eclipse Diagram for HST (Hawaiian Standard Time)

The diagrams above of the Total Lunar Eclipse of September 27-28, 2015 by Fred Espenak, www.EclipseWise.com are licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

From the eastern and central USA and Canada (time zones EDT, CDT and MDT), the eclipse begins in the early evening a few hours after sunset. From the western-most USA and Canada (time zone PDT), the early stages of the eclipse occur before the Moon rises.

Fortunately, observers throughout most of North America will be treated to the total phase of the eclipse (commonly known as totality). Only observers in the western 3/4 of Alaska and Hawaii will miss totality.

Some people may be puzzled that the Moon's motion in these diagrams is from west to east (right to left), instead of its daily east to west (left to right) motion across the sky. THe diagrams show the Moon's RELATIVE motion with respect to the Earth's shadows and the background stars, which is WEST to EAST (right to left in the Northern Hemisphere). At the same time, the Moon, Earth's shadow and the stars all rise in the east and set in the west.

April 15, 2014 Lunar Eclipse Sequence
The total lunar eclipse of April 15, 2014 was widely visible from the USA.
This sequence of images captures the eclipse from start (right) to finish (left).
(click to see larger image)

Times and Phases of September's Total Lunar Eclipse

From start to finish, September's lunar eclipse lasts about 3 hours and 20 minutes (not including the penumbral phases which are very difficult to see). The partial eclipse begins as the Moon's eastern edge slowly moves into Earth's umbral shadow. During the partial phases, it takes 1 hour 4 minutes for the Moon's orbital motion to carry it entirely within Earth's dark umbra.

The color and brightness of the totally eclipsed Moon can vary considerably from one eclipse to another. Dark eclipses are caused by volcanic gas and dust which filters and blocks much of the Sun's light from reaching the Moon. Although Indonesia's Mount Kelud has undergone recent volcanic eruptions, it has not produced enough dust and gas to significantly darken September's eclipse. Expect the total phase to appear bright red or orange, which is typical (see: What Will the 2014 and 2015 Lunar Eclipses Look Like?). After the total phase ends, it is once again followed by a partial eclipse as the Moon gradually leaves the umbral shadow. The Visual Appearance of Lunar Eclipses describes what each of these eclipse phases looks like.

The total phase of a lunar eclipse is called totality. At this time, the Moon is completely immersed within Earth's dark umbral shadow. During the September 27/28 eclipse, totality will last 1 hour 12 minutes. This is much longer than the last total lunar eclipse on April 4, 2015, which only lasted 4.5 minutes.

The major phases of the eclipse occur as follows (all times are EDT or Eastern Daylight Time). The partial eclipse commences with first umbral contact at 09:07 pm EST. Totality begins at 10:11 pm EDT and lasts until 11:23 pm EDT. The partial phases end at 12:27 am EDT.

Eclipse times for time zones throughout in the United States and Canada are shown in the following table. Most areas of the United States currently observe Daylight Saving Time (DST). Two notable exceptions are Arizona (although the Navajo Nation does observe Daylight Saving Time) and Hawaii. Observers in Arizona should use the times listed under Pacific Daylight Time (PDT).

The table below also includes the times of the start and end of the penumbral stages of the eclipse. However, they are not observable because the penumbral shadow is very faint.

* Event occurs on morning ofSeptember 28, 2015

Eclipse times for other time zones can be calculated by taking the difference between local time and Greenwich and adding it to the tabulated GMT times. For more information, see Time Zones. (Note: Although GMT is still in common use, it has actually been replaced by Coordinated Universal Time (UTC), which is based on atomic time.)

To determine the Moon's altitude at each stage of the eclipse as seen from your city or location, see Javascript Lunar Eclipse Explorer. This web page allows you to calculate the viewing circumstances of all lunar eclipses visible from your city over a five-thousand year period.

Visibility of the Total Lunar Eclipse of September 27-28, 2015

September's lunar eclipse is well placed for North and South America, the Atlantic, Europe and Africa. Observers in westernmost North America and eastern Europe and Africa will miss some stages of the eclipse because they occur before moonrise or after moonset. No part of the eclipse is visible from eastern Asia, Japan, Australia or New Zealand.

Preceeding and following the eclipse are approximately hour-long penumbral phases but these are faint and quite difficult to see. The more visually interesting and photogenic partial and total phases always take center stage (see The Pale Penumbral Phase).

Map showing the global visibility of the Total Lunar Eclipse of September 27-28, 2015.
(Click here to see larger version of this map)

The Visibility Map above for the Total Lunar Eclipse of September 27-28, 2015 by Fred Espenak, www.EclipseWise.com is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

The map above shows the geographic regions of visibility for each phase of the eclipse. The entire eclipse is visible from start to finish in the white (unshaded) portion of the map, while none of the eclipse can be seen from the dark gray areas.

For anyone located in the light gray shaded region labeled Eclipse at Moonrise, this means that the Moon will rise while some phase of the eclipse is in progress. The contact curves labeled U1, U2, U3, and U4 represent each phase of the eclipse (see the key above). If you are west (left) of a particular curve, that phase occurs before moonrise and you will not see it. However, if you are east (right) of a curve, that phase occurs after moonrise and you will see it (weather permitting).

For example, on the above map, California, Oregon and Washington all lie west (left) of the U1 curve (partial eclipse begins) and east (right) of the curve U2 (total eclipse begins). This means that from this region, the Moon rises during the partial phases before totality begins.

For observers located within the second light gray shaded region labeled Eclipse at Moonset, the Moon sets while some phase of the eclipse is already in progress. If you are east (right) of a particular curve (U1, U2, U3, or U4), that phase occurs after moonset and you will not see it. However, if you are west (left) of a contact curve, that phase occurs before moonset and you will see it (weather permitting).

All total eclipses begin with penumbral and partial phases before totality. After the total phase, the eclipse ends with more partial and penumbral phases. Since the penumbral phases of the eclipse are so difficult to see, we will ignore them.

The Total Lunar Eclipse of July 16, 2000 was a very long total eclipse (1 hour 47 minutes)
that won't be exceeded for over a thousand years.
(click for larger image)

Wonderful Totality

At the instant of mid-totality (09:47 pm EDT), the Moon will lie at the zenith from a location near Belem, Brazil. At this time, the umbral magnitude peaks at 1.2765 as the Moon's northern limb passes 3.5 arc-minutes south of the shadow's central axis. Eclipse magnitude is the fraction of the Moon's diameter immersed in Earth's umbral shadow at greatest eclipse. This value is always 1.0 or larger for total eclipses.

At mid-totality, the Moon's southern limb lies 9.3 arc-minutes from the southern edge of the umbra and 37.0 arc-minutes from the shadow center (an arc-minute is 1/60 of a degree; the Moon's apparent diameter is 33.5 arc-minutes during this eclipse making it a Super Moon). The northern half of the Moon will appear much darker than the southern half because it lies deeper in the umbra.

This can be seen in the eclipse diagrams shown earlier. Since Earth's umbral shadow is darker in the center than at the edge, the Moon's appearance will likely change dramatically with time as the total phase progresses. A large variation in shadow brightness can be expected and observers are encouraged to estimate the Danjon value at different times during totality (Danjon Brightness Scale).

This image of the Total Lunar Eclipse of Oct. 28, 2004 was shot just before
the total phase ended. The northern edge of the Moon was very close
to the edge of Earth's umbral shadow making it appear much brighter than
the rest of the Moon.
(click for larger image)

This could be an excellent opportunity for budding astronomers to test their observing skills. Try recording your estimates of the Moon's brightness every ten minutes during totality using the Danjon Brightness Scale. Compare your results with your companions and classmates and discover how the Moon's appearance changes during the total eclipse. The brightness of the totally eclipsed Moon is very sensitive to the presence of volcanic dust in Earth's atmosphere. As part of a continuing research project, Dr. Richard Keen has been using reports of lunar eclipse brightnesses to calculate a history of optical thicknesses of volcanic dust layers (see: What Will the 2014 and 2015 Lunar Eclipses Look Like?). If you'd like to help Dr. Keen by making eclipse observations, you can contact him .

The amount of dust and sulfur dioxide in Earth's atmosphere also has an effect on the diameter of the umbral shadow. Amateur astronomers with telescopes can make careful timings of when some of the Moon's major craters enter or exit the umbra. Such observations are valuable in determining the enlargement of Earth's shadow. A table of crater predictions identifies twenty well-defined craters useful for this purpose. For more information, see: Crater Timings During Lunar Eclipses.

An eclipse of the Moon also presents a tempting subject to photograph. Since the Moon appears quite small in the sky, you will need a fairly powerful telephoto lens (300 mm or more) or a small telescope to attach to your camera. ISO 400 (either digital or film) is a good choice. For more information on equipment, film, recommended exposures and additional tips, see How to Photograph a Lunar Eclipse.

Unlike solar eclipses, lunar eclipses are completely safe to watch. Protective filters are not necessary and neither is a telescope. A lunar eclipse can be observed with nothing more than the naked eye. However, a pair of binoculars will magnify the view and make the red coloration brighter and easier to see. A standard pair of 7x35 or 7x50 binoculars is sufficient.

During the eclipse, the Moon will be at its descending node in Pisces. The Moon is also at perigee (September 28 at 01:46 UT). This means that the Moon will appear 12.9% larger than it did during the April 04 eclipse (33.5 vs. 29.7 arc-minutes).

The media will probably make a big deal about this eclipse happening during a Super Moon. Just don't believe any nonsense you hear that this will cause earthquakes, tidal waves or any other kind of natural disasters. The Moon will just appear a little larger than average (4.7% larger).

During totality, the autumn constellations are well placed for viewing and the brighter stars can be used for magnitude comparisons. The center of the Great Square of Pegasus lies 24° to the northwest, its brightest star being Alpheratz (m = +2.02). Deneb Kaitos (m = +2.04) in Cetus is 20° south of the eclipsed Moon, while Hamal (m = +2.01) is 35° to the northeast, Aldebaran (m = +0.87) is 65° to the east, and Almach (m = +2.17) is 48° to the north. Although relatively faint, the planet Uranus (m = +5.7) lies 14° northeast of the Moon during totality.

Although total eclipses of the Moon are of limited scientific value, they are remarkably beautiful events which do not require expensive equipment. They help to cultivate interest in science and astronomy in children and to provide a unique learning opportunity for families, students and teachers. To the nature lover and naturalist, the lunar eclipse can be appreciated and celebrated as an event which vividly illustrates our place among the planets in the solar system. The three dimensional reality of our universe comes alive in a graceful celestial ballet as the Moon swings through Earth's shadow. Hope for clear skies, dress warmly and enjoy the show!

The Pale Penumbral Phase

The penumbral phases of the eclipse have been mentioned several times as being difficult to see. In fact, the start of the penumbral eclipse (at 8:12 pm EDT) is impossible to see. Even when half of the Moon's disk is immersed in the pale penumbral shadow, no trace of it is visible with or without a telescope. This is why the penumbral phases of the eclipse are downplayed here.

When about 2/3 of the Moon's disk is in the penumbra, the first hint of the shadow becomes visible (about 08:45 pm EDT). It is a very diffuse and subtle shading that gradually grows stronger. About ten minutes (about 08:57 pm EDT) before the partial phase begins, the penumbral shading is much more apparent, but the Moon's disk is only diminished slightly in brightness.

The most interesting stage of the penumbral phase is during the last two minutes just before the edge of the Moon's disk begins to enter the umbral shadow (the start of the partial eclipse). Now the penumbral shading is apparent even to the naked eye. Still, this stage of the eclipse literally pales in comparison to the dynamic partial phases and the gloriously beautiful totality.

After totality and the partial phases end (12:27 am EDT), the penumbral phases occur in reverse. The Moon exits the penumbra at 01:23 am EDT but no trace of the shadow is visible to mark the event.

To get an idea of what to expect during the deeper penumbral phases, see Visual Appearance of Lunar Eclipses.

Total Lunar Eclipses of 2014-2015
Total Lunar Eclipse of 2014 Apr 15	Total Lunar Eclipse of 2014 Oct 08	Total Lunar Eclipse of 2015 Apr 04	Total Lunar Eclipse of 2015 Sep 28

Click on any of the above figures for a closer look.

Tetrads: Four Consecutive Total Lunar Eclipses

September's eclipse is the second of two total lunar eclipses in 2015. The first eclipse was on April 4 and was visible from the western USA.

These two eclipses are the last of four consecutive total lunar eclipses, each separated by six months - a series known as a tetrad. The first and second eclipses of the tetrad occurred on April 15, 2014 and October 8, 2014 .

During the 5000-year period from 2000 BCE through 3000 CE, there are 3479 total lunar eclipses. Approximately 16.3% (568) of these belong to one of the 142 tetrads occurring over this period. The mechanism causing tetrads involves the eccentricity of Earth's orbit in conjunction with the timing of eclipse seasons. During the present millennium, the first eclipse of every tetrad occurs during the period February to July. In later millennia, the first eclipse date gradually falls later in the year because of precession.

Italian astronomer Giovanni Schiaparelli first pointed out that the frequency of tetrads is variable over time. He noticed that tetrads were relatively plentiful during one 300-year interval, while none occurred during the next 300 years. For example, there are no tetrads from 1582 to 1908, but 17 tetrads occur from 1909 to 2156. The ~565-year period of the tetrad "seasons" is tied to the slowly decreasing eccentricity of Earth's orbit. Consequently, the frequency of tetrads is gradually decreasing (Meeus, 2004). In the distant future when Earth's eccentricity is 0 (about 470,000 years from now), tetrads will no longer be possible.

The umbral magnitudes of the total eclipses making up a tetrad are all relatively small. For the 300-year period 1901 to 2200, the largest umbral magnitude of a tetrad eclipse is 1.4251 on 1949 Apr 13. For comparison, the magnitudes of some other total eclipses during this period are much larger. Two examples are the total eclipses of July 16, 2000 and June 26, 2029 with umbral magnitudes of 1.7684 and 1.8436, respectively.

The table below gives the dates of each eclipse in the 8 tetrads occurring during the 21st century. The last tetrad prior to 2014 was in 2003-04 while the next group is in 2032-33.

Two catalogs have been prepared, each listing all tetrads over 3000-year periods:

• Catalog of Lunar Eclipse Tetrads: -2999 to 0000 (3000 BCE to 1 BCE)
• Catalog of Lunar Eclipse Tetrads: 0001 to 3000 (1 CE to 3000 CE)

This multiple exposure sequence shows both partial and total phases of the Total Lunar Eclipse of January 21, 2000.
(click for larger image)

Eclipse Frequency and Future Eclipses

During the five millennium period from 2000 BCE through 3000 CE, there are 7,718 eclipses of the Moon [1] (including both partial and total eclipses). From 0 to 3 lunar eclipses (partial or total) occur each year. The last time three total lunar eclipses occurred in one calendar year was in 1982. On average, partial eclipses slightly outnumber total eclipses by 7 to 6 [2].

The last total lunar eclipse visible from the entire continental United States occurred on Apr. 4, 2015. North Americans will have their next opportunity (after Sept. 27-28) to see a total lunar eclipse on Jan. 31, 2018. Visit Eclipses During 2015 for a complete report on all eclipses occurring over the year.

The table below lists every lunar eclipse from 2014 through 2020. Click on the eclipse Date to see a description, map and diagram of each eclipse. Although penumbral lunar eclipses are included in this list, they are quite difficult to observe because of their subtlety. (The penumbra is a partial shadow that permits some direct sunlight to reach the Moon.)

The Umbral Eclipse Magnitude is the fraction of the Moon's diameter immersed in the umbra at maximum eclipse. Partial eclipses have a magnitude less than 1. For magnitudes of 1 or greater, the eclipse is total. For negative magnitudes, the eclipse is penumbral. The Eclipse Duration is the duration of the entire eclipse. For total eclipses the duration of the total phase is also listed in bold.

Footnotes

[1] Only eclipses where the Moon passes through Earth's umbral shadow are included in these values. A minor type of eclipse is the penumbral eclipse, which occurs when the Moon passes through Earth's faint penumbral shadow. Penumbral eclipses are rarely discernible to the naked eye and are of lesser importance than umbral eclipses.

[2] Penumbral eclipses are excluded from these statistics.

Geographic abbreviations (used above): n = north, s = south, e = east, w = west, c = central

The Total Lunar Eclipse of July 16, 2000 as seen from Maui.
(click for larger image)