Aquarius is an equatorial constellation of the zodiac, between Capricornus and Pisces. Its name is Latin for "water-carrier" or "cup-carrier", and its old astronomical symbol is (♒︎), a representation of water. Aquarius is one of the oldest of the recognized constellations along the zodiac. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is found in a region often called the Sea due to its profusion of constellations with watery associations such as Cetus the whale, Pisces the fish, and Eridanus the river.
NGC 2264 is the designation number of the New General Catalogue that identifies two astronomical objects as a single object: the Cone Nebula, and the Christmas Tree Cluster. Two other objects are within this designation but not officially included, the Snowflake Cluster, and the Fox Fur Nebula. All of the objects are located in the Monoceros constellation and are located about 720 parsecs or 2,300 light-years from Earth. Due to its relative proximity and large size, it is extremely well-studied. NGC 2264 is sometimes referred to as the Christmas Tree Cluster and the Cone Nebula. However, the designation of NGC 2264 in the New General Catalogue refers to both objects and not the cluster alone. In December 2023, NASA released Christmas holiday-related images by the James Webb Space Telescope, including the Christmas Tree Galaxy Cluster and others.
The Helix Nebula is a planetary nebula (PN) located in the constellation Aquarius. Discovered by Karl Ludwig Harding, most likely before 1824, this object is one of the closest of all the bright planetary nebulae to Earth. The distance, measured by the Gaia mission, is 655±13 light-years. It is similar in appearance to the Cat's Eye Nebula and the Ring Nebula, whose size, age, and physical characteristics are similar to the Dumbbell Nebula, varying only in its relative proximity and the appearance from the equatorial viewing angle. The Helix Nebula has sometimes been referred to as the "Eye of God" in pop culture, as well as the "Eye of Sauron".
Circinus is a small, faint constellation in the southern sky, first defined in 1756 by the French astronomer Nicolas-Louis de Lacaille. Its name is Latin for compass, referring to the drafting tool used for drawing circles. Its brightest star is Alpha Circini, with an apparent magnitude of 3.19. Slightly variable, it is the brightest rapidly oscillating Ap star in the night sky. AX Circini is a Cepheid variable visible with the unaided eye, and BX Circini is a faint star thought to have been formed from the merger of two white dwarfs. Two sun-like stars have planetary systems: HD 134060 has two small planets, and HD 129445 has a Jupiter-like planet. Supernova SN 185 appeared in Circinus in 185 AD and was recorded by Chinese observers. Two novae have been observed more recently, in the 20th century.
The Red Spider Nebula is a planetary nebula located near the heart of the Milky Way, in the northwest of the constellation Sagittarius. The nebula has a prominent two-lobed shape, possibly due to a binary companion or magnetic fields and has an S-shaped symmetry of the lobes – the lobes opposite each other appear similar. This is believed to be due to the presence of a companion to the central white dwarf. However, the gas walls of the two lobed structures are not at all smooth, but rather are rippled in a complex way.
The Cat's Eye Nebula is a planetary nebula in the northern constellation of Draco, discovered by William Herschel on February 15, 1786. It was the first planetary nebula whose spectrum was investigated by the English amateur astronomer William Huggins, demonstrating that planetary nebulae were gaseous and not stellar in nature. Structurally, the object has had high-resolution images by the Hubble Space Telescope revealing knots, jets, bubbles and complex arcs, being illuminated by the central hot planetary nebula nucleus (PNN). It is a well-studied object that has been observed from radio to X-ray wavelengths.
The Eagle Nebula is a young open cluster of stars in the constellation Serpens, discovered by Jean-Philippe de Cheseaux in 1745–46. Both the "Eagle" and the "Star Queen" refer to visual impressions of the dark silhouette near the center of the nebula, an area made famous as the "Pillars of Creation" imaged by the Hubble Space Telescope. The nebula contains several active star-forming gas and dust regions, including the aforementioned Pillars of Creation. The Eagle Nebula lies in the Sagittarius Arm of the Milky Way.
The Eskimo Nebula, also known as the Clown-faced Nebula, Lion Nebula, or Caldwell 39, is a bipolar double-shell planetary nebula (PN). It was discovered by astronomer William Herschel in 1787. The formation resembles a person's head surrounded by a parka hood. It is surrounded by gas that composed the outer layers of a Sun-like star. The visible inner filaments are ejected by a strong wind of particles from the central star. The outer disk contains unusual, light-year-long filaments.
The Saturn Nebula is a planetary nebula in the constellation Aquarius. It appears as a greenish-yellowish hue in a small amateur telescope. It was discovered by William Herschel on September 7, 1782, using a telescope of his own design in the garden at his home in Datchet, England, and was one of his earliest discoveries in his sky survey. The nebula was originally a low-mass star that ejected its layers into space, forming the nebula. The central star is now a bright white dwarf star of apparent magnitude 11.5. The Saturn Nebula gets its name from its superficial resemblance to the planet Saturn with its rings nearly edge-on to the observer. It was so named by Lord Rosse in the 1840s, when telescopes had improved to the point that its Saturn-like shape could be discerned. William Henry Smyth said that the Saturn Nebula was one of Struve's nine "Rare Celestial Objects".
NGC 1275 is a type 1.5 Seyfert galaxy located around 237 million light-years away in the direction of the constellation Perseus. NGC 1275 is a member of the large Perseus Cluster of galaxies.
NGC 6822 is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884, with a six-inch refractor telescope. It is the closest non-satellite galaxy to the Milky Way, but lies just outside its virial radius. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter.
Sh2-279 is an HII region and bright nebulae that includes a reflection nebula located in the constellation Orion. It is the northernmost part of the asterism known as Orion's Sword, lying 0.6° north of the Orion Nebula. The reflection nebula embedded in Sh2-279 is popularly known as the Running Man Nebula.
NGC 4656/57 is a highly warped edge-on barred spiral galaxy located in the local universe 30 million light years away from Earth in the constellation Canes Venatici. This galaxy is sometimes called the Hockey Stick Galaxy or the Crowbar Galaxy. Its unusual shape is thought to be due to an interaction between NGC 4656, NGC 4631, and NGC 4627. The galaxy is a member of the NGC 4631 Group.
NGC 6751, also known as the Glowing Eye Nebula, is a planetary nebula in the constellation Aquila. It is estimated to be about 6,500 light-years away.
The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus.
NGC 2023 is an emission and reflection nebula in the equatorial constellation of Orion. It was discovered by the German-born astronomer William Herschel on 6 January 1785. This reflection nebula is one of the largest in the sky, with a size of 10 × 10 arcminutes. It is located at a distance of 1,300 ly (400 pc) from the Sun, and is positioned ~15′ to the northeast of the Horsehead Nebula.
NGC 346 is a young open cluster of stars with associated nebula located in the Small Magellanic Cloud (SMC) that appears in the southern constellation of Tucana. It was discovered August 1, 1826 by Scottish astronomer James Dunlop. J. L. E. Dreyer described it as, "bright, large, very irregular figure, much brighter middle similar to double star, mottled but not resolved". On the outskirts of the cluster is the multiple star system HD 5980, one of the brightest stars in the SMC.
The Soap Bubble Nebula, Ju 1 is a planetary nebula in the constellation Cygnus, near the Crescent Nebula. The nebula derives its name from its symmetrical spherical shape which resembles a soap bubble.
IC 2177 is a region of nebulosity that lies along the border between the constellations Monoceros and Canis Major. It is a roughly circular H II region centered on the Be star HD 53367. This nebula was discovered by Welsh amateur astronomer Isaac Roberts and was described by him as "pretty bright, extremely large, irregularly round, very diffuse."
Sh2-7 is an emission nebula in the Scorpius constellation. The nebula is around the star Delta Scorpii. It lies next to a large reflection nebula, Sh2-1.
