On the evening of Thursday, January 20, 2000, a total eclipse of the Moon will be visible from all of North and South America including the USA and Canada. The event will also be visible from western Europe on the morning of January 21.

An eclipse of the Moon can only take place at Full Moon, and only if the Moon passes through some portion of the Earth's shadow. The shadow is actually composed of two cone-shaped components, one inside the other. The outer or penumbral shadow is a zone where some portion of the Sun's rays are blocked. In contrast, the inner or umbral shadow is a region devoid of all direct sunlight.

Astronomers recognize three basic types of lunar eclipses:

1. Penumbral Lunar Eclipse

• The Moon passes through the Earth's penumbral shadow.
• These events are of academic interest only since they are subtle and quite difficult if not impossible to observe.

2. Partial Lunar Eclipse

• A portion of the Moon passes through the Earth's umbral shadow.
• These events are easy to see, even with the unaided eye.

3. Total Lunar Eclipse

• The entire Moon passes through the Earth's umbral shadow.
• These events are quite striking for the vibrant range of colors the Moon can take on during totality.

As the Moon orbits the Earth every 29.5 days, it usually passes north or south of Earth's shadows so no eclipse takes place. But every once in a while, the Moon passes through some portion of the Earth's penumbral or umbral shadows and one of the above three types of eclipses occurs.

During a total lunar eclipse, the Earth blocks all direct sunlight from the Moon. Astronauts on the Moon would then see the Earth eclipsing the Sun. (They would see a bright red ring around the Earth as they watched all the sunrises and sunsets happening simultaneousely arounf the world!) While the Moon remains completely within Earth's umbral shadow, indirect sunlight still manages to reach and illuminate it. However, this sunlight must first pass deep through the Earth's atmosphere which filters out most of the blue colored light. The remaining light is a deep red or orange in color and is much dimmer than pure white sunlight. The Earth's atmosphere also bends or refracts some of this light so that a small fraction of it can reach and illuminate the Moon.

The total phase of a lunar eclipse is so interesting and beautiful precisely because of the filtering and refracting effect of Earth's atmosphere. If the Earth had no atmosphere, then the Moon would be completely black during a total eclipse. Instead, the Moon can take on a range of colors from dark brown and red to bright orange and yellow. The exact appearance depends on how much dust and clouds are present in Earth's atmosphere. Total eclipses tend to be very dark after major volcanic eruptions since these events dump large amounts of volcanic ash into Earth's atmosphere. During the total lunar eclipse of December 1992, dust from Mount Pinatubo rendered the Moon nearly invisible.

All total eclipses start with a penumbral followed by a partial eclipse, and end with a partial followed by a penumbral eclipse (the total eclipse is sandwiched in the middle). Since the penumbral phases of the eclipse are so difficult to see, we will ignore them.

From start to finish, January's lunar eclipse lasts nearly three and a half hours. The partial eclipse begins as the Moon's eastern edge slowly moves into the Earth's umbral shadow. During the partial phases, it takes just over an hour for the Moon's orbital motion to carry it entirely within the Earth's dark umbra. Since no major volcanic eruptions have taken place recently, the Moon will probably take on a vivid red or orange color during the 77 minute long total phase. After the total phase ends, it is once again followed by a partial eclipse as the Moon gradually leaves the umbral shadow.

Unlike solar eclipses, lunar eclipses are completely safe to watch. You don't need any kind of protective filters. You don't even need a telescope. You can watch the lunar eclipse with nothing more than your own two eyes. If you have a pair of binoculars, they will help magnify the view and will make the red coloration brighter and easier to see.

The following diagrams show the Moon's path through Earth's shadows (higher resolution versions of the above figure). The times of major stages of the eclipse are given for a number of time zones. Please choose the diagram for your own time zone.

Some people may be puzzled that the Moon's motion is from west to east in these diagrams, instead of its daily east to west motion. However, the Moon actually moves WEST to EAST with respect to the Earth's shadow and the stars.

• Eclipse Diagram for Eastern Standard Time Zone (35k GIF)
• Eclipse Diagram for Central Standard Time Zone (35k GIF)
• Eclipse Diagram for Mountain Standard Time Zone (35k GIF)
• Eclipse Diagram for Pacific Standard Time Zone (35k GIF)
• Eclipse Diagram for Greenwich Mean Time (35k GIF)

• Eclipse Diagram (no times, minimum labels) (25k GIF)

Permission is freely granted to reproduce these eclipse diagrams when accompanied by an acknowledgment:

During the five millennium period from 2000BC through 3000 AD, there are 7,718 eclipses¹ of the Moon (including both partial and total). There are anywhere from 0 to 3 lunar eclipses (including partial and total) each year. The last time that three total lunar eclipses occurred in one calendar year was in 1982. Partial eclipses slightly outnumber total eclipses by 7 to 6.

The last total lunar eclipse visible from the United States occured on Sept. 26, 1996. North Americans won't have another opportunity to see a total lunar eclipse until May 16, 2003. However, on July 16, 2000, Hawaii, Australia and Asia will see the longest total lunar eclipse in 140 years (since 1859). It will last 1 hour and 47 minutes.

The table below lists every lunar eclipse from 2000 through 2005. Click on the eclipse Date to see a map and diagram of an eclipse. Click on the Region of Eclipse Visibility to see a detailed description of an eclipse. Although penumbral lunar eclipses are included in this list, they are usually quite difficult to observe because of their subtlety. The penumbra is a partial shadow which still permits some direct sunlight to reach the Moon.

The Umbral Magnitude is the fraction on the Moon's diameter immersed in the umbra at maximum eclipse. For values greater than 1.0, it is a total eclipse. For negative values, it is a penumbral eclipse. The Total Duration is the duration of the total phase (total eclipses only).

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

We will list links for live web coverage of the eclipse as they become available.

• High Moon Webcast - Olivier Staiger.
• Lunar Eclipse Live Webcast - Reuben H. Fleet Science Center.
• Lunar Eclipse Live Webcast - Dr. Jon Saken (south Florida)
• Lunar Eclipse Live Webcast - Paul Goelz (Rochester Hills, MI)
• Lunar Eclipse Live Webcast - Dr. Dale Ireland (Seattle, WA)
• Lunar Eclipse Live Webcast - TriValley Astronomers (Livermore, CA)
• Lunar Eclipse Live Webcast - Spacewatch (New York, NY)

• More on January's eclipse: eclipse.gsfc.nasa.gov/eclipse/OH/OH2000.html
• Lunar Eclipses from 1991 to 2000: eclipse.gsfc.nasa.gov/eclipse/LEdecade/LEdecade1991.html
• Lunar Eclipses from 2001 to 2010: eclipse.gsfc.nasa.gov/eclipse/LEdecade/LEdecade2001.html
• 5,000 Year Catalog of Lunar Eclipses: eclipse.gsfc.nasa.gov/eclipse/LEcat5/LEcatalog.html
• Tips on Photographing Lunar Eclipses: www.mreclipse.com/LEphoto/LEphoto.html

References

• Espenak, F., 1989, Fifty Year Canon of Lunar Eclipses: 1986-2035, Sky Publishing Corp., Cambridge, MA.
• Espenak, F., 1999, "Eclipses During 2000", Observer's Handbook - 2000, Royal Astronomical Society of Canada, Toronto, Ontario.
• O'Meara, Stephen, "An Awesome Eclipse of the Moon", Sky and Telescope, January 2000 issue.

All eclipse calculations are by Fred Espenak, and he assumes full responsibility for their accuracy. Some of the information presented in this catalog is based on data originally published in Fifty Year Canon of Lunar Eclipses: 1986 - 2035.

Permission is freely granted to reproduce this data when accompanied by an acknowledgment:

Photos of January's Lunar Eclipse!

WebMaster: Fred Espenak Planetary Systems Branch - Code 693 e-mail: fred.espenak@nasa.gov NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771 USA