Articles About Moon (60)

Full Moon above hill and forest in Slovenia November 15, 2016.

What Is a Supermoon?

The Full Moon on May 26, 2021, was a Super Flower Moon. Supermoon, Full Moon—what's the difference?

2 kids watching seagulls at low tide on a beach

What Causes Tides?

The gravitational pull of the Moon and the Sun makes the water in the oceans bulge, causing a continuous change between high and low tide.

The Hunter's Moon

October’s Full Moon is the Hunter’s Moon. It's also called Travel Moon, Dying Grass Moon, Blood Moon, or Sanguine Moon.

Full Moon Names

Full Moons had given names in many ancient cultures. The Full Moon names we use today often reflect nature like Harvest Moon.

Zoomed in image of the Full Moon with its surface of craters and mountains.

Full Moon – the Moonlight Phase

The 3rd primary phase of the Moon, the Full Moon is the moment its disk is illuminated by the Sun's rays.

What's a Blood Moon?

A total lunar eclipse is often called a Blood Moon because of the red glow the eclipsed Moon gets. The term is also used for four total lunar eclipses that occur in a row.

2021 Cosmic Calendar

Celestial events and highlights of 2021 and 2022 including supermoons, solar and lunar eclipses, meteor showers, solstices, and equinoxes.

Illustration of the Moon's position in space in relation to Earth and the Sun at New Moon.

The New Moon

When is the next New Moon? New Moon is when the Sun and Moon are aligned, with the Sun and Earth on opposite sides of the Moon.

Full Moon peeking through branches. Blue and foggy background.

What Is a Blue Moon?

'Once in a blue moon', suggests something is very rare. But just how rare is a Blue Moon?

Harvest Supermoon rises over the campus of West Virginia University in Morgantown WV on November 13, 2016.

Harvest Moon in September or October?

The Harvest Moon varies between September or October in the Northern Hemisphere. It is the Full Moon nearest the autumnal (fall) equinox.

Solar and Lunar Eclipses

Solar and lunar eclipses, why they occur, when the next eclipse is, and from where you can see them.

Magnetic Declination

A compass needle doesn't point to the geographical North Pole but to magnetic north. Did you know that it usually doesn't point to the magnetic North Pole either?

Underside of an airplane visible in front of a half Moon during the day with a blue sky in the background.

First Quarter Moon

The 1st Quarter Moon is a primary Moon phase when we can see exactly half of the Moon's surface lit up. Which half depends on where you are on Earth.

Total Solar Eclipse

Total solar eclipses occur when the New Moon comes between the Sun and Earth and casts the darkest part of its shadow, the umbra, on Earth.

Waxing Gibbous Moon

The Waxing Gibbous Moon is an intermediate Moon phase that starts after the First Quarter Moon and lasts until the Full Moon.

Illustrative comparison of a Supermoon and Micromoon.

What Is Lunar Perigee and Apogee?

Lunar perigee is when the Moon is closest to Earth on its orbit. The point where the Moon is farthest from Earth is known as lunar apogee.

A Last Quarter Moon, also called Half Moon, where the left half of the Moon is lit up.

Third Quarter Moon

The Third or Last Quarter Moon is when the opposite half of the Moon is illuminated compared to the First Quarter.

Total Lunar Eclipses

A total lunar eclipse happens when Earth's shadow blocks the direct light from the Sun reaching the Full Moon.

Waning Gibbous Moon

The Waning Gibbous Moon is an intermediate Moon phase that starts after the Full Moon and lasts until half of the Moon's face remains lit-up at Third Quarter Moon.

Only a thin crescent of the Sun is visible against a dark sky during this partial solar eclipse Malaysia on 9 March 2016.

What Is a Solar Eclipse?

Solar eclipses happen when the Moon moves between Sun and Earth, blocking the Sun's rays and casting a shadow on Earth.

$Image of Full Moon red in color due to refraction with dark sky in the background.$

Lunar Eclipse: Red Moon

Find out why a totally eclipsed Moon turns a shade of red.

November: Beaver Moon

The Full Moon in November is named after beavers. It is also called Frost Moon and Mourning Moon, depending on the winter solstice.

Astronomy Glossary - Terms & definitions

Astronomical Glossary - Terms & Definitions

What do astronomers really mean when they use those technical terms?

Waxing Crescent Moon

The Waxing Crescent Moon phase starts after New Moon and lasts until half of the Waxing Moon's surface is illuminated at First Quarter Moon.

Solar Eclipse Myths

The solar eclipse has inspired many mythical stories and influenced human behavior. Even today, eclipses of the Sun are considered bad omens in many cultures.

Dark New Moon night with the star filled sky in the background and fir trees in the foreground.

What Is a Micromoon?

A Micromoon is the name given to a Full or New Moon when the Moon is farthest from Earth.

What Is a Black Moon?

A Black Moon can be the third New Moon in a season with four New Moons or the second New Moon in the same calendar month, or even no New Moon at all.

Black background with rays extending out from a circle and a bright light from the top of the circle.

How Often Do Solar Eclipses Happen?

There are between 2 and 5 solar eclipses every year, each one visible only in a limited area.

Waning Crescent Moon

During the Waning Crescent Moon phase, the lit-up part of the Waning Moon shrinks from the Third Quarter Moon until it disappears from view at New Moon.

Dark blue sky in the background with a glowing ring around the Sun. The center of the sun is dark.

Annular Solar Eclipse

An annular solar eclipse is when the Moon moves in front of the Sun but leaves the outer edge of the Sun visible as a ring of fire.

Image of a waterfall at night with one bright moon bow and a faint moon bow above it. Dark skies and city lights in the background.

What Are Moonbows?

Moonbows occur when the Moon’s light is reflected and refracted off water droplets in the air.

What Is the Umbra?

The umbra is the dark center portion of a shadow. The Moon's umbra causes total solar eclipses, and the Earth's umbra is involved in total and partial lunar eclipses.

Image of a faint eclipsed Moon behind a brightly it castle.

Watching Lunar Eclipses

A lunar eclipse can be seen with the naked eye, unlike solar eclipses, which have special safety requirements.

Picture with fields in the foreground and a crescent shaped Sun with Moon in front of it. Cloudy skies in the background.

Partial Solar Eclipse

A partial solar eclipse happens when the Moon only partially covers the Sun.

Illustration of altitude and azimuth in the celestial sphere.

Altitude & Azimuth: The Horizontal Coordinate System

Learn how to use altitude (elevation) and azimuth angles to locate any object in the sky, such as stars, planets, satellites, the Sun, or the Moon.

A howling lone gray wolf in snow-covered landscape.

January: Wolf Moon

The January Full Moon is named after howling wolves. In some cultures, it was known as Old Moon, Ice Moon, Snow Moon, and the Moon after Yule.

Why 3 Shadows?

Objects cast 3 different shadows: umbra, penumbra, and antumbra. Why are there 3 types of shadows and how do they determine the type of an eclipse?

Full moon on the horizon at the end of a dock.

The Moon Illusion

Some days, the Full Moon at the horizon looks larger than a normal Full Moon. Does the Moon really change size or is this an illusion?

Illustration showing all the different Moon phases next to one another

The Lunar Month

A lunar month is the time it takes the Moon to pass through all of the Moon phases, usually measured from a New Moon the next New Moon.

Solar Eclipses in History

Solar eclipses were historically seen as omens that bring about death and destruction. People in many ancient civilizations tried their best to understand them.

A partially eclipsed Moon in the night sky. A little over half of the Moon is covered by a reddish shade.

What Is a Partial Lunar Eclipse?

A partial lunar eclipse happens when the Earth moves between the Sun and the Moon, but they are not precisely aligned.

Penumbral lunar eclipse illustration with positions of Sun, Earth, and Moon in space

What Is the Penumbra?

The penumbra is the lighter outer part of a shadow. The Moon's penumbra causes partial solar eclipses, and the Earth's penumbra is involved in penumbral lunar eclipses.

December: Cold Moon

The December Full Moon is called the Cold Moon, Long Nights Moon, the Moon before Yule, Oak Moon, and Wolf Moon.

August: Sturgeon Moon

The Full Moon in August is named after the lake sturgeon. Other names for this Full Moon include Grain Moon, Green Corn Moon, Fruit Moon, and Barley Moon.

Annular solar eclipse illustration with positions of Earth, Moon, and Sun in space

What Is the Antumbra?

The antumbra is the lighter part of a shadow that forms at a certain distance from the object casting the shadow. It is involved in annular solar eclipses and planet transits.

Penumbral Lunar Eclipse

A penumbral lunar eclipse occurs when the outer shadow of Earth falls on the Moon's face. It is easy to miss this type of lunar eclipse.

Hybrid Solar Eclipse

A hybrid eclipse or annular/total eclipse starts as a total solar eclipse but changes into an annular solar eclipse. Why is that so? When is the next hybrid solar eclipse?

Eclipse Magnitude

Eclipse magnitude is a number that astronomers associate with solar or lunar eclipses. What does it mean?

March: Worm Moon

The Full Moon in March is the Worm Moon. It is also called Lenten Moon, Crow Moon, Crust Moon, Chaste Moon, Sugar Moon, and Sap Moon.

Close-up of the far side of the Moon with partial Earth in the background.

The Moon's Far Side

The notion that there is a permanently dark side of the Moon is wrong. What is true, is that there is a far side of the Moon, a side we never see from Earth

A Full Moon shines over a field of corn ready to be harvested. Dark blue night sky in the background.

September: Harvest or Corn Moon

The September Full Moon is usually the Harvest Moon, but this depends on the equinox. It is also called Full Corn Moon or Barley Moon.

February: Snow Moon

The February Full Moon is named after the snow on the ground. Some Native American tribes named this the Hunger Moon, others called it the Storm Moon.

Pink wild ground phlox are a native flower to North America.

April: Pink Moon

Pink Moon comes from Pink Wild Ground Phlox which bloom in spring. Other names for this Full Moon are Sprouting Grass Moon, Fish Moon, Hare Moon, Egg Moon, and Paschal Moon.

Paddleboarders below the strawberry moon at Barceloneta beach, Barcelona, Spain.

June: Strawberry Moon

The wild strawberries that start to ripen gave name to the Full Moon in June. Other names are Rose Moon, Hot Moon, and Mead Moon.

Lupine wildflowers above Park City, Utah.

May: Flower Moon

The Full Moon in May is known as the Flower Moon. Other names include the Corn Planting Moon, and the Milk Moon, while some named it the Hare moon.

Crescent Moon with dark blue sky in the background. The unlit part of the Moon has a dim glow. Bright star shines to the left of the Moon.

What Is Earthshine?

Earthshine is a dull glow that occurs when the Sun’s light reflects off the Earth's surface and illuminates the unlit portion of the Moon.

White-tailed deer buck near a canola field.

July: Buck Moon

The Full Moon in July is the Buck Moon. Is is also called Thunder Moon, Hay Moon, and Wort Moon.

Is a Blue Moon Blue?

A Blue Moon is a type of a Full Moon. It can also be a rare Moon that looks blue due to atmospheric dust particles.

Silhouette of two photographers looking at the Full Moon.

Taking Pictures of the Moon

With the right equipment, a little time and planning, you can take great pictures of the Moon.

The Moon Phases

There are four primary Moon phases and four intermediate phases. New Moon First Quarter Full Moon Third or Last Quarter Waxing and Waning Crescent Moon.