Earth's Moon
The Moon is Earth's only natural satellite and our closest celestial neighbor.
The stargazer’s field guide
Look up. The night sky is waiting.
A plain-language reference to the objects you can actually see — planets, constellations, deep-sky wonders, and the events worth staying up for.
Observation catalog
Mars
Mars is the fourth planet from the Sun and the outermost of the rocky, or terrestrial, worlds in our solar system.
Jupiter
Jupiter is the largest planet in our solar system, a gas giant so massive that it could contain more than a thousand Earths by volume.
Orion
Orion is one of the most recognizable constellations in the entire night sky, visible from almost everywhere on Earth at some point during the year.
Ursa Major (the Great Bear)
Ursa Major, known as the Great Bear, is one of the most recognizable constellations in the northern sky.
Cassiopeia
Cassiopeia is one of the most recognizable constellations in the northern sky, famous for its distinctive W or M shape formed by five bright stars.
The Andromeda Galaxy
The Andromeda Galaxy is the nearest large galaxy to our own Milky Way.
The Orion Nebula
The Orion Nebula is one of the most famous and easily observed deep-sky objects in the entire night sky.
The Pleiades
The Pleiades is one of the most famous and easily recognizable star clusters in the night sky.
Total Solar Eclipse
A total solar eclipse is one of the most dramatic sights in all of nature.
The Perseid Meteor Shower
The Perseid meteor shower is one of the most widely watched and reliably enjoyable annual sky events.
Lunar Eclipse
A lunar eclipse is a celestial event where the Moon passes into Earth's shadow.
Red Giant Stars
Red giant stars are a fascinating stage in the life of many stars, including our Sun.
White Dwarf Stars
White dwarf stars are the dense, glowing cores left behind after certain stars have exhausted their nuclear fuel.
Neutron Stars
Neutron stars are the incredibly dense remnants of massive stars that have ended their lives in supernova explosions.
Saturn
Saturn is the sixth planet from the Sun and the second-largest planet in our solar system, after Jupiter.
Venus
Venus is the second planet from the Sun and the closest planetary neighbor to Earth.
Mercury
Mercury is the smallest planet in our solar system and the closest to the Sun.
Scorpius
Scorpius is one of the most recognizable constellations in the sky, with a distinctive shape that truly resembles a scorpion.
Cygnus (the Swan)
Cygnus, known as the Swan, is one of the most recognizable constellations in the northern sky.
Crux (the Southern Cross)
Crux, commonly known as the Southern Cross, is the smallest of all 88 officially recognized constellations.
The Crab Nebula
The Crab Nebula is one of the most famous and intensively studied deep-sky objects in the entire night sky.
The Ring Nebula
The Ring Nebula is one of the most famous and easily recognized deep-sky objects in the summer sky.
The Hercules Globular Cluster
The Hercules Globular Cluster is one of the most celebrated deep-sky objects in the northern sky.
The Northern Lights (Aurora)
The Northern Lights, also known as the aurora borealis, are a natural light display in Earth's sky, predominantly seen in high-latitude regions around the Arctic.
The Summer Solstice
The summer solstice is the moment each year when the Sun reaches its northernmost point in the sky as seen from Earth.
The Supermoon
A supermoon is a popular name for a full moon that happens near the closest point in the Moon's orbit around Earth.
Black Holes
Black holes are among the most fascinating and mysterious objects in the universe.
Main Sequence Stars
Main sequence stars are the most common type of star in the universe, including our own Sun.
Supernovae
A supernova is one of the most energetic events in the universe.