How often does a total lunar eclipse happen

What’s special about November’s lunar eclipse?

The last total lunar eclipse for three years occurs on November 8, 2022, with the next occurring on March 14, 2025 — though we will continue to see partial and penumbral lunar eclipses during that time.

A lunar eclipse occurs when the Sun, Earth, and Moon align so that the Moon passes into Earth’s shadow. In a total lunar eclipse, the entire Moon falls within the darkest part of Earth’s shadow, called the umbra. When the Moon is within the umbra, it will turn a reddish hue. Lunar eclipses are sometimes called “Blood Moons” because of this phenomenon.

How can I observe the eclipse?

You don’t need any special equipment to observe a lunar eclipse, although binoculars or a telescope will enhance the view and the red color. A dark environment away from bright lights makes for the best viewing conditions.

Totality ― the stage of the eclipse where the Moon is entirely in Earth’s shadow ― will be visible across North and Central America and in Ecuador, Colombia, and western portions of Venezuela and Peru. In Puerto Rico, the Moon sets just after totality begins. The eclipse is also visible in Asia, Australia, and New Zealand. Viewers in Alaska and Hawaii will have the opportunity to see every stage of the eclipse.

What if it’s cloudy or I’m not in the viewing region?

Join in online: Live Stream the November 8 Lunar Eclipse

You can also visit NASA’s Dial-a-Moon for a visualization of the eclipse.

What can I expect to observe?

What else can I see tonight?

The Moon will be in the constellation Aries. NASA provides a monthly skywatching tips series that will highlight additional targets to focus on in between monitoring the eclipse.

Why does the Moon turn red during a lunar eclipse?

The same phenomenon that makes our sky blue and our sunsets red causes the Moon to turn red during a lunar eclipse. It’s called Rayleigh scattering. Light travels in waves, and different colors of light have different physical properties. Blue light has a shorter wavelength and is scattered more easily by particles in Earth’s atmosphere than red light, which has a longer wavelength.

Red light, on the other hand, travels more directly through the atmosphere. When the Sun is overhead, we see blue light throughout the sky. But when the Sun is setting, sunlight must pass through more atmosphere and travel farther before reaching our eyes. The blue light from the Sun scatters away, and longer-wavelength red, orange, and yellow light pass through.

During a lunar eclipse, the Moon turns red because the only sunlight reaching the Moon passes through Earth’s atmosphere. The more dust or clouds in Earth’s atmosphere during the eclipse, the redder the Moon will appear. It’s as if all the world’s sunrises and sunsets are projected onto the Moon.

A solar eclipse occurs when the Moon passes between the Sun and Earth, casting the Moon's shadow on Earth.  A solar eclipse can only happen during a New Moon.  The Moon's orbit is titled 5 degrees to Earth's orbit around the Sun.  Therefore a solar eclipse is a relatively rare phenomena and a Total or Annular eclipse even more rare, with the Hybrid eclipse the rarest of all.  

To understand the difference between a Total and Annular eclipse of the Sun, it must be understood that the Moon has an elliptical orbit around Earth.  In fact, the Moon's distance from Earth varies from a minimum of 221,000 to a maximum of 252,000 miles.  Therefore the Moon's apparent size in our sky will vary by 13%.  When the Moon's orbit is toward its minimum distance from Earth, the Moon will appear visually as a larger disk than the Sun.  If an eclipse occurs during this time, it will be a Total solar eclipse because the Moon has totally obscured the Sun's disk, producing the beautiful solar corona ejecting outward from the Sun.  One important element to remember though is that the Moon's shadow will obviously become narrower as it is cast from the Moon to Earth (in a shape of a cone with the wide end being at the Moon and the narrow end on Earth).  Therefore the path of totality on Earth is narrow.  It is also very short-lived as the Moon is moving quickly away from its perfect location of being situated between the Sun and Earth. 

An Annular solar eclipse is different than Totality in that it occurs when the Moon is closer to its maximum distance from Earth in its orbit.  If an eclipse happens during this situation, the Moon will appear visually smaller than the Sun and its shadow cast will not be long enough to reach Earth.  What reaches Earth is the antumbral or "negative" shadow.  If you are within the antumbral shadow, you will see a solar eclipse where a thin ring or annulus of bright sunlight surrounds the Moon.  Therefore Annular solar eclipses are still spectacular in that they are almost Total, but the solar corona is not seen due to the brightness of the annulus.  Like a Total eclipse, the Annular solar eclipse will have a narrow path on Earth with short duration, most often less than 10 minutes. 

A Hybrid eclipse is especially rare in that an Annular eclipse can change to a Total eclipse, or vice versa, along the eclipse path.  Due to Earth's curvature, Earth may move through the Antumbral shadow (Annular eclipse) and Umbral shadow (Total eclipse) along different points of the eclipse path.   

DO NOT observe a solar eclipse with the naked eye.  Serious eye damage can result.  Use approved solar filters or cut a pin hole in a shoe box and watch the Sun's light cast through the pin hole onto a smooth surface such as cardboard.  The only portion of a solar eclipse which is safe to view without filters is the brief time during totality.  Otherwise all partial solar eclipses need approved filters.  For approved filters, look for a certification of International Standard ISO 12312-2.  The next solar eclipse which will be visible in the United States will occur on April 8, 2024.

DATES OF UPCOMING TOTAL AND ANNULAR SOLAR ECLIPSES AND LOCATIONS OF BEST VIEWING

Eclipse predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, eclipse.gsfc.nasa.gov

** Eclipse Visible in United States

A Lunar eclipse occurs when the Sun casts Earth's shadow onto the Moon.  For this to happen, the Earth must be physically between the Sun and Moon with all three bodies lying on the same plane of orbit.  A lunar eclipse can only occur during a Full Moon and when the Moon passes through all or a portion of Earth's shadow.  

The outer portion of the shadow cast from Earth is known as the penumbral shadow, which is an area where Earth obstructs only a part of the Sun's light from reaching the Moon.  The umbral shadow is the "inner" shadow, which is the area where Earth blocks all direct sunlight from reaching the Moon.  A penumbral lunar eclipse is subtle and very difficult to observe.  A partial lunar eclipse is when a portion of the Moon passes through the Earth's umbral shadow.  Finally, a total lunar eclipse is when the entire Moon passes into the Earth's umbral shadow.  During a total lunar eclipse, the sequence of eclipses are penumbral, partial, total, partial and back to penumbral.  

Unlike solar eclipses, a total lunar eclipse lasts a few hours, with totality itself usually averaging anywhere from about 30 minutes to over an hour.  This is due to the large relative size of Earth over the Moon (the Moon's diameter is only about 2150 miles), therefore casting a large umbral shadow on the Moon.  In addition, lunar eclipses are more frequent than their solar counterparts.  There are zero to three lunar eclipses per year (although possibly not all at the same location on Earth) where the Moon passes through at least a portion of the Earth's umbral shadow (producing a partial to total eclipse).  As stated above in the solar eclipse explanation, the Moon's orbit is tilted 5 degrees from Earth's orbit.  For an eclipse to occur, the Moon and Earth have to be on the same orbital plane with the Sun, so the Earth's shadow can be cast onto the Moon from the Sun.  This is why lunar eclipses only occur on average one or two times a year instead of every month.  

Even though the Moon is immersed in the Earth's umbral shadow, indirect sunlight will still reach the Moon thus illuminating it slightly.  This is because indirect sunlight reaches the Moon and also the Earth's atmosphere will bend a very small portion of sunlight onto the Moon's surface.  Many times during lunar totality, the color of the Moon will take on a dark red hue or brown/orange color.  As sunlight passes through Earth's atmosphere, the blue-light is scattered out.  The amount of illumination of the Moon will vary depending on how much dust is in the Earth's atmosphere.  The more dust present in the atmosphere, the less illuminated the Moon will be. 

Lunar eclipses are safe to be viewed by the naked eye, through binoculars or a telescope.  Below is a table which shows partial and total lunar eclipses visible in the United States.

Eclipse predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, eclipse.gsfc.nasa.gov

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