109 Sentences With "celestial hemisphere" | Random Sentence Generator

The LMC is visible in the southern celestial hemisphere, where it can look to stargazers like a hazy cloud.

Luhman 16 is located in the southern celestial hemisphere in the constellation Vela. As of July 2015, its components are the nearest-known celestial objects in this constellation outside the Solar system. Its celestial coordinates: RA = , Dec = .

A star chart of the entire Northern Sky, centered on the north celestial pole The northern celestial hemisphere, also called the Northern Sky, is the northern half of the celestial sphere; that is, it lies north of the celestial equator. This arbitrary sphere appears to rotate westward around a polar axis due to Earth's rotation. At any given time, the entire Northern Sky is visible from the geographic North Pole, while less of this hemisphere is visible the further south the observer is located. The southern counterpart is the southern celestial hemisphere.

Pictor culminates each year at 9 p.m. on 17 March. Its position in the far Southern Celestial Hemisphere means that the whole constellation is visible to observers south of latitude 26°N, and parts become circumpolar south of latitude 35°S.

An HDF counterpart in the southern celestial hemisphere was created in 1998: the HDF-South (HDF-S).Williams et al. (2000) Created using a similar observing strategy, the HDF-S was very similar in appearance to the original HDF.Casertano et al.

A star chart of the entire Southern Sky, centered on the south celestial pole The southern celestial hemisphere, also called the Southern Sky, is the southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly fixed stars form constellations, appears to rotate westward around a polar axis due to Earth's rotation. At any given time, the entire Southern Sky is visible from the geographic South Pole, while less of this hemisphere is visible the further north the observer is located. The northern counterpart is the northern celestial hemisphere.

The proposal continues to spawn a great deal of controversy over the use of the site for science. The TMT project is a response to recommendation in 2000 from the US National Academy of Sciences that a thirty-meter telescope be a top priority, and that it be built within the decade. Urgency in construction is due to the competitive nature of science with the European-Extremely Large Telescope also under construction. The two projects are also complementary, in that the EELT would only view the Southern Celestial Hemisphere, while Mauna Kea offers the best views of the Northern Celestial Hemisphere.

Fornax () is a constellation in the southern celestial hemisphere, partly ringed by the celestial river Eridanus. Its name is Latin for furnace. It was named by French astronomer Nicolas Louis de Lacaille in 1756. Fornax is one of the 88 modern constellations.

In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between −6.66° and −25.20°. Its position in the southern celestial hemisphere means that the whole constellation is visible to observers south of 65°N.

In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between −11.68° and −25.20°. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 65°N.

Eridanus () is a constellation in the southern celestial hemisphere. It is represented as a river. 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 the sixth largest of the modern constellations.

Columba is a faint constellation designated in the late sixteenth century, remaining in official use, with its rigid limits set in the 20th century. Its name is Latin for dove. It takes up 1.31% of the southern celestial hemisphere and is just south of Canis Major and Lepus.

Pisces is a constellation of the zodiac and is located in the Northern celestial hemisphere. Its name is the Latin plural for fish. It lies between Aquarius to the west and Aries to the east. The ecliptic and the celestial equator intersect within this constellation and in Virgo.

The Radial Velocity ExperimentRadial Velocity Experiment – RAVE measures until 2010 the radial velocities and elemental abundances of a million stars, predominantly in the southern celestial hemisphere. The 6dF multi-object spectrograph on the 1.2 m UK Schmidt telescope of the Anglo-Australian Observatory will be applied for this purpose.

The Microscopium Void is a void—a roughly rectangular region of relatively empty space, bounded by incomplete sheets of galaxies from other voids in the southern celestial hemisphere. It lies within the boundaries of the constellation of Microscopium. It was discovered and named by South African astronomer Tony Fairall in 1984.

Corona Borealis is a small constellation in the Northern Celestial Hemisphere. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations. Its brightest stars form a semicircular arc. Its Latin name, inspired by its shape, means "northern crown".

Frederick de Houtman ( – 21 October 1627) was a Dutch explorer, navigator, and colonial governor who sailed on the first Dutch expedition to the East Indies from 1595 until 1597, during which time he made observations of the southern celestial hemisphere and contributed to the creation of 12 new southern constellations.

In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates range from the north celestial pole south to 65.40°. Its position in the far northern celestial hemisphere means that the whole constellation is only visible to observers in the northern hemisphere.

This analysis produced a credible region of 150 deg2 with a probability of 50% or 610 deg2 with a probability of 90% located mainly in the Southern Celestial Hemisphere, in the rough direction of (but much farther than) the Magellanic Clouds. For comparison, the area of the constellation Orion is 594 deg2.

Scutum is a small constellation. Its name is Latin for shield, and it was originally named Scutum Sobiescianum by Johannes Hevelius in 1684. It lies entirely in the southern celestial hemisphere and its four brightest stars form a narrow diamond shape. It is one of the 88 IAU designated constellations defined in 1922.

The Leo Supercluster is a supercluster in the Northern Celestial Hemisphere that stretches across the constellations Ursa Major and Leo. It covers an area approximately 130 megaparsecs long by 60 megaparsecs wide. The redshifts of member galaxy clusters range from 0.032 to 0.043. The brightest cluster in the system is Abell 1185.

Perseus OB1 is an OB association in the Northern Celestial Hemisphere in the constellation Perseus. It is centered around the double cluster (NGC 869 and NGC 884), and has lent its name to the Perseus Arm of the Milky Way. The brightest member of the association is the blue supergiant 9 Persei.

Pictor A, around 485 million light-years away in the constellation Pictor, is a double-lobed broad-line radio galaxy and a powerful source of radio waves in the Southern Celestial Hemisphere. From a supermassive black hole at its centre, a relativistic jet shoots out to an X-ray hot spot 300,000 light years away.

The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of eight segments (illustrated in infobox). In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between 39.71° and 25.54°. It has a counterpart—Corona Australis—in the Southern Celestial Hemisphere.

An object with an axial tilt between 90 degrees and 180 degrees is rotating in the opposite direction to its orbital direction. Regardless of inclination or axial tilt, the north pole of any planet or moon in the Solar System is defined as the pole that is in the same celestial hemisphere as Earth's north pole.

Libra is a constellation of the zodiac and is located in the Southern celestial hemisphere. Its name is Latin for weighing scales, and its symbol is 20px (Unicode ♎). It is fairly faint, with no first magnitude stars, and lies between Virgo to the west and Scorpius to the east. Beta Librae, also known as Zubeneschamali, is the brightest star in the constellation.

Energy equivalent to three solar masses was emitted as gravitational waves. The signal was seen by both LIGO detectors in Livingston and Hanford, with a time difference of 7 milliseconds due to the angle between the two detectors and the source. The signal came from the Southern Celestial Hemisphere, in the rough direction of (but much further away than) the Magellanic Clouds.

The rings of Saturn are almost certainly visible from the upper reaches of its atmosphere. The rings are so thin that from a position on Saturn's equator, they would be almost invisible. However, from anywhere else on the planet, they could be seen as a spectacular arc stretching across half the celestial hemisphere. Delta Octantis is the south pole star of Saturn.

He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment. Lacaille Latinised the name to Pixis [sic] Nautica on his 1763 chart. The Ancient Greeks identified the four main stars of Pyxis as the mast of the mythological Jason's ship, Argo Navis.

Moving the Burrell Schmidt to Kitt Peak in Arizona made it possible to continue the "early results" program to the Northern Celestial Hemisphere. Bidelman directed the Warner and Swasey Observatory from 1970–1975, and was a Professor of astronomy from 1970–1986. In June 1970, Bidelman began as Chairman and Director. Bidelman's office was at the old Taylor Road Observatory,Pesch, Peter & Bidelman, William P. "Preface".

Leo Minor is a small and faint constellation in the northern celestial hemisphere. Its name is Latin for "the smaller lion", in contrast to Leo, the larger lion. It lies between the larger and more recognizable Ursa Major to the north and Leo to the south. Leo Minor was not regarded as a separate constellation by classical astronomers; it was designated by Johannes Hevelius in 1687.

Cancer is one of the twelve constellations of the zodiac and is located in the Northern celestial hemisphere. Its name is Latin for crab and it is commonly represented as one. Its astrological symbol is♋. Cancer is a medium-size constellation with an area of 506 square degrees and its stars are rather faint, its brightest star Beta Cancri having an apparent magnitude of 3.5.

Aries is one of the constellations of the zodiac. It is located in the Northern celestial hemisphere between Pisces to the west and Taurus to the east. The name Aries is Latin for ram, and its symbol is 20px (Unicode ♈), representing a ram's horns. It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.

Piscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish", in contrast with the larger constellation Pisces, which represents a pair of fishes. Before the 20th century, it was also known as Piscis Notius. Piscis Austrinus was one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations.

Gemini is one of the constellations of the zodiac and is located in the northern celestial hemisphere. It was one of the 48 constellations described by the 2nd century AD astronomer Ptolemy, and it remains one of the 88 modern constellations today. Its name is Latin for twins, and it is associated with the twins Castor and Pollux in Greek mythology. Its symbol is 18px (Unicode ♊).

Corona Australis is a constellation in the Southern Celestial Hemisphere. Its Latin name means "southern crown", and it is the southern counterpart of Corona Borealis, the northern crown. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. The Ancient Greeks saw Corona Australis as a wreath rather than a crown and associated it with Sagittarius or Centaurus.

This feature is consistent with the Earth moving at some 627 km/s towards the constellation Virgo. At some points, the "cold spot" deviates 140 µK colder than the average CMB temperature. The radius of the "cold spot" subtends about 5°; it is centered at the galactic coordinate lII = 207.8°, bII = −56.3° (equatorial: α = , δ = ). It is, therefore, in the Southern Celestial Hemisphere, in the direction of the constellation Eridanus.

Delphinus (Pronounced or ) is a small constellation in the Northern Celestial Hemisphere, close to the celestial equator. Its name is the Latin version for the Greek word for dolphin (). It is one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations recognized by the International Astronomical Union. It is one of the smaller constellations, ranked 69th in size.

Corvus is a small constellation in the Southern Celestial Hemisphere. Its name means "crow" in Latin. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it depicts a raven, a bird associated with stories about the god Apollo, perched on the back of Hydra the water snake. The four brightest stars, Gamma, Delta, Epsilon, and Beta Corvi, form a distinctive quadrilateral in the night sky.

Collinder 135, known sometimes as the Pi Puppis Cluster, is an open cluster in Puppis constellation. It consists of four stars visible also to naked eye, and a widespread population of stars. It lies in the southern celestial hemisphere near a rich star field. The main component is the star Pi Puppis, which gives to the cluster its common name; it is an orange supergiant with a visual magnitude of 2.71.

In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between 77.69° and 46.68°. Its position in the Northern Celestial Hemisphere means that the whole constellation is visible to observers north of 12°S. High in the northern sky, it is circumpolar (that is, it never sets in the night sky) to viewers in the British Isles, Canada and the northern United States.

Earth rotating within the celestial sphere. In this view, the Southern Celestial Hemisphere is below the celestial equator, the middle parallel (in cyan). In the context of astronomical discussions or writing about celestial mapping, it may also simply then be referred to as the Southern Hemisphere. For the purpose of celestial mapping, the sky is considered by astronomers as the inside of a sphere divided in two halves by the celestial equator.

Crater is a small constellation in the southern celestial hemisphere. Its name is the latinization of the Greek krater, a type of cup used to water down wine. One of the 48 constellations listed by the second-century astronomer Ptolemy, it depicts a cup that has been associated with the god Apollo and is perched on the back of Hydra the water snake. There is no star brighter than third magnitude in the constellation.

Pictor is a constellation in the Southern Celestial Hemisphere, located between the star Canopus and the Large Magellanic Cloud. Its name is Latin for painter, and is an abbreviation of the older name Equuleus Pictoris (the "painter's easel"). Normally represented as an easel, Pictor was named by Abbé Nicolas-Louis de Lacaille in the 18th century. The constellation's brightest star is Alpha Pictoris, a white main-sequence star around 97 light-years away from Earth.

The SST was initially deployed for testing and evaluation at the White Sands Missile Range in New Mexico. On December 6, 2013, it was announced that the telescope system would be moved to the Naval Communication Station Harold E. Holt in Exmouth, Western Australia, as part of the Australia-U.S. Space Situational Awareness Initiative. From there it will able to observe the Southern Celestial Hemisphere and collect data for the US Space Surveillance Network.

In the southern-sky catalog Uranometria Argentina, 82 G. Eridani (sometimes abbreviated to "82 Eridani") is the 82nd star listed in the constellation Eridanus. The Argentina catalog, compiled by the 19th-century astronomer Benjamin Gould, is a southern celestial hemisphere analog of the more famous Flamsteed catalog, and uses a similar numbering scheme. 82 G. Eridani, like other stars near the Sun, has held on to its Gould designation, even while other more distant stars have not.

Gliese 1 is a red dwarf in the constellation Sculptor, which is found in the southern celestial hemisphere. It is one of the closest stars to the Sun, at a distance of 14.2 light years. Because of its proximity to the Earth it is a frequent object of study and much is known about its physical properties and composition. However, with an apparent magnitude of about 8.5 it is too faint to be seen with the naked eye.

Covering 179 square degrees and hence 0.433% of the sky, Corona Borealis ranks 73rd of the 88 modern constellations by area. Its position in the Northern Celestial Hemisphere means that the whole constellation is visible to observers north of 50°S. It is bordered by Boötes to the north and west, Serpens Caput to the south, and Hercules to the east. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "CrB".

Canis Major is a constellation in the southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin for "greater dog" in contrast to Canis Minor, the "lesser dog"; both figures are commonly represented as following the constellation of Orion the hunter through the sky. The Milky Way passes through Canis Major and several open clusters lie within its borders, most notably M41.

"Steer" is the first single from Missy Higgins' second album, On a Clear Night. The song was released in Australia on 14 April 2007 and became the most-added track that same week. Higgins stated that the song was "about steers" and that she wrote it after overlooking the southern celestial hemisphere from a bay in Western Australia.Time Off Magazine Matt Connors' interview with Missy Higgins(2006) The song has instrument backings of acoustic guitar and drums.

Leo is one of the constellations of the zodiac, lying between Cancer the crab to the west and Virgo the maiden to the east. It is located in the Northern celestial hemisphere. Its name is Latin for lion, and to the ancient Greeks represented the Nemean Lion killed by the mythical Greek hero Heracles meaning 'Glory of Hera' (known to the ancient Romans as Hercules) as one of his twelve labors. Its symbol is 20px (Unicode ♌).

In the equatorial coordinate system the right ascension coordinates of these borders lie between and , while the declination coordinates are between 2.33° and 36.61°. Its position in the Northern Celestial Hemisphere means that the whole constellation is visible to observers north of 53°S. Pegasus with the foal Equuleus next to it, as depicted in Urania's Mirror, a set of constellation cards published in London c.1825. The horses appear upside-down in relation to the constellations around them.

NGC 1579 (also known as the Northern Trifid) is a diffuse nebula located in the constellation of Perseus. It is referred to as the Northern Trifid because of its similar appearance to the Trifid Nebula, which is located in the southern celestial hemisphere of the sky. It is a H II region, a region of star formation. The star cluster contains the emission-line star LkHα 101, which provides much of the ionizing radiation in the nebula.

Antlia (; from Ancient Greek ἀντλία) is a constellation in the Southern Celestial Hemisphere. Its name means "pump" in Latin and Greek; it represents an air pump. Originally Antlia Pneumatica, the constellation was established by Nicolas-Louis de Lacaille in the 18th century, though its name was later abbreviated by John Herschel. Located close to the stars forming the old constellation of the ship Argo Navis, Antlia is completely visible from latitudes south of 49 degrees north.

Northern Hemisphere shaded blue. The hemispheres appear to be unequal in this image due to Antarctica not being shown, but in reality are the same size. Northern Hemisphere from above the North Pole The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's North Pole.

He devised 14 new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. Mensa was the only constellation that did not honor an instrument symbolic of the Age of Enlightenment. Sir John Herschel proposed shrinking the name to one word in 1844, noting that Lacaille himself had abbreviated some of his constellations thus. Although the stars of Mensa do not feature in any ancient mythology, the mountain it is named after has a rich mythology.

Northern part of galaxy cluster Abell 1758. The sky-coverage of the 1958 catalog was limited to declinations north of –27°, the original southern limit of POSS. To rectify this and other shortcomings, the original catalog was later revised and supplemented with an additional catalogthe "Southern Survey"of rich galaxy clusters from those parts of the south celestial hemisphere that had been omitted from the original catalog. The Southern Survey added a further 1,361 rich clusters to Abell's original Northern Survey.

Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only 25 light-years from the Sun, and, together with Arcturus and Sirius, one of the most luminous stars in the Sun's neighborhood. It is the fifth-brightest star in the night sky, and the second-brightest star in the northern celestial hemisphere, after Arcturus.

Card 32 of Urania's Mirror depicts Noctua the owl, perched on the tail of Hydra, the serpent. Noctua (Latin: owl) was a constellation near the tail of Hydra in the southern celestial hemisphere, but is no longer recognized. It was introduced by Alexander Jamieson in his 1822 work, A Celestial Atlas, and appeared in a derived collection of illustrated cards, Urania's Mirror. Now designated Asterism a, the owl was composed of the stars 4 Librae and 54–57 Hydrae, which range from 4th to 6th magnitude.

Capella , designated α Aurigae (Latinized to Alpha Aurigae, abbreviated Alpha Aur, α Aur), is the brightest star in the constellation of Auriga, the sixth- brightest star in the night sky, and the third-brightest in the northern celestial hemisphere after Arcturus and Vega. A prominent object in the northern winter sky, it is circumpolar to observers north of 44°N. Its name meaning "little goat" in Latin, Capella depicted the goat Amalthea that suckled Zeus in classical mythology. Capella is relatively close, at from the Sun.

In 1835, after suffering several illnesses, Julia visited the Cape of Good Hope in South Africa with her parents to recover. It was common for Europeans living in India to visit South Africa to convalesce after an illness. While there, she met the British astronomer and photochemist Sir John Herschel, who was observing the southern celestial hemisphere. She also met Charles Hay Cameron, twenty years her senior and a reformer of Indian law and education who later invested in coffee plantations in what is now Sri Lanka.

Covering 237.1 square degrees and hence 0.575% of the sky, Ara ranks 63rd of the 88 modern constellations by area. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 22°N. Scorpius runs along the length of its northern border, while Norma and Triangulum Australe border it to the west, Apus to the south, and Pavo and Telescopium to the east respectively. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union, is "Ara".

Covering 206.3 square degrees and hence 0.5002% of the sky, Apus ranks 67th of the 88 modern constellations by area. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 7°N. It is bordered by Ara, Triangulum Australe and Circinus to the north, Musca and Chamaeleon to the west, Octans to the south, and Pavo to the east. The three- letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "Aps".

Telescopium is a minor constellation in the southern celestial hemisphere, one of twelve named in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is a Latinized form of the Greek word for telescope. Telescopium was later much reduced in size by Francis Baily and Benjamin Gould. The brightest star in the constellation is Alpha Telescopii, a blue-white subgiant with an apparent magnitude of 3.5, followed by the orange giant star Zeta Telescopii at magnitude 4.1.

Microscopium ("the Microscope") is a minor constellation in the southern celestial hemisphere, one of twelve created in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. The name is a Latinised form of the Greek word for microscope. Its stars are faint and hardly visible from most of the non-tropical Northern Hemisphere. The constellation's brightest star is Gamma Microscopii of apparent magnitude 4.68, a yellow giant 2.5 times the Sun's mass located 223 ± 8 light-years distant.

Taurus (Latin for "the Bull") is one of the constellations of the zodiac and is located in the Northern celestial hemisphere. Taurus is a large and prominent constellation in the northern hemisphere's winter sky. It is one of the oldest constellations, dating back to at least the Early Bronze Age when it marked the location of the Sun during the spring equinox. Its importance to the agricultural calendar influenced various bull figures in the mythologies of Ancient Sumer, Akkad, Assyria, Babylon, Egypt, Greece, and Rome.

The constellation Mensa as it can be seen by the naked eye. Mensa is a constellation in the Southern Celestial Hemisphere near the south celestial pole, one of twelve constellations drawn up in the 18th century by French astronomer Nicolas-Louis de Lacaille. Its name is Latin for table, though it originally commemorated Table Mountain and was known as Mons Mensae. One of the eighty-eight constellations designated by the International Astronomical Union (IAU), it covers a keystone-shaped wedge of sky 153.5 square degrees in area.

Barnard's Star is a red dwarf about six light-years away from Earth in the constellation of Ophiuchus. It is the fourth-nearest-known individual star to the Sun after the three components of the Alpha Centauri system, and the closest star in the northern celestial hemisphere. Its stellar mass is about 14% of the Sun's. Despite its proximity, the star has a dim apparent magnitude of +9.5 and is invisible to the unaided eye; it is much brighter in the infrared than in visible light.

Early 17th century representation of the southern celestial hemisphere in a table from Acta Eruditorum, 1713 From the South Pole, in good visibility conditions, the Southern Sky features over 2,000 fixed stars that are easily visible to the naked eye, while about 20,000 to 40,000 with the aided eye. In large cities, about 300 to 500 stars can be seen depending on the extent of light and air pollution. The farther north, the fewer are visible to the observer. The brightest stars are all larger than the Sun.

RMC 136a1 (usually abbreviated to R136a1) is one of the most massive and luminous stars known, at and 6.2 million , and is also one of the hottest, at around . It is a Wolf–Rayet star at the center of R136, the central concentration of stars of the large NGC 2070 open cluster in the Tarantula Nebula (30 Doradus). The cluster can be seen in the far southern celestial hemisphere with binoculars or a small telescope, at magnitude 7.25. R136a1 itself is 10,000 times fainter and can only be resolved using speckle interferometry.

Horologium (Latin , the pendulum clock, from Greek , ) is a constellation of six stars faintly visible in the southern celestial hemisphere. It was first described by the French astronomer Nicolas-Louis de Lacaille in 1756 and visualized by him as a clock with a pendulum and a second hand. In 1922 the constellation was redefined by the International Astronomical Union (IAU) as a region of the celestial sphere containing Lacaille's stars, and has since been an IAU designated constellation. Horologium's associated region is wholly visible to observers south of 23°N.

If more energy is available, other elements will be ionized and green and blue nebulae become possible. By examining the spectra of nebulae, astronomers infer their chemical content. Most emission nebulae are about 90% hydrogen, with the remaining helium, oxygen, nitrogen, and other elements. Some of the most prominent emission nebulae visible from the northern hemisphere are the North America Nebula (NGC 7000) and Veil Nebula NGC 6960/6992 in Cygnus, while in the south celestial hemisphere, the Lagoon Nebula M8 / NGC 6523 in Sagittarius and the Orion Nebula M42.

Photograph of Telescopium Herschelii with constellations Gemini, Auriga, Perseus and the Pleiades Telescopium Herschelii on a celestial globe at the Herschel Museum of Astronomy, Bath Illustrated in Urania's Mirror (1825), next to Lynx Telescopium Herschelii (Latin for Herschel's telescope), also formerly known as Tubus Hershelli Major, is a former constellation in the northern celestial hemisphere. Maximilian Hell established it in 1789 to honour Sir William Herschel's discovery of the planet Uranus. It fell out of use by the end of the 19th century. Psi2 Aurigae at apparent magnitude 4.8 was the constellation's brightest star.

The constellation of Pyxis, the compass, as it can be seen by the naked eye Covering 220.8 square degrees and hence 0.535% of the sky, Pyxis ranks 65th of the 88 modern constellations by area. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 52°N. It is most visible in the evening sky in February and March. A small constellation, it is bordered by Hydra to the north, Puppis to the west, Vela to the south, and Antlia to the east.

Covering 238.9 square degrees and hence 0.579% of the sky, Antlia ranks 62nd of the 88 modern constellations by area. Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 49°N. Hydra the sea snake runs along the length of its northern border, while Pyxis the compass, Vela the sails, and Centaurus the centaur line it to the west, south and east respectively. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union, is "Ant".

Ruggles 1999:18 The concentric circles the stars trace out are lines of celestial latitude, known as declination. The arc connecting the points on the horizon due East and due West (if the horizon is flat) and all points midway between the Celestial Poles is the Celestial Equator which has a declination of 0°. The visible declinations vary depending where you are on the globe. Only an observer on the North Pole of Earth would be unable to see any stars from the Southern Celestial Hemisphere at night (see diagram below).

Triangulum Australe is a small constellation in the far Southern Celestial Hemisphere. Its name is Latin for "the southern triangle", which distinguishes it from Triangulum in the northern sky and is derived from the almost equilateral pattern of its three brightest stars. It was first depicted on a celestial globe as Triangulus Antarcticus by Petrus Plancius in 1589, and later with more accuracy and its current name by Johann Bayer in his 1603 Uranometria. The French explorer and astronomer Nicolas Louis de Lacaille charted and gave the brighter stars their Bayer designations in 1756.

Cetus in this card from Urania's Mirror (1825). The French astronomer Nicolas Louis de Lacaille first described the constellation in French as le Fourneau Chymique (the Chemical Furnace) with an alembic and receiver in his early catalogue, before abbreviating it to le Fourneau on his planisphere in 1752, after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment.

Early depiction c.1756, when known as le Chevalet et la Palette; Canopus of Carina (the keel, or the hull, of the ship) seen at upper right The French astronomer Abbé Nicolas-Louis de Lacaille first described Pictor as le Chevalet et la Palette (the easel and palette) in 1756, after observing and cataloguing 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised 14 new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honored instruments that symbolised the Age of Enlightenment.

The French astronomer Nicolas Louis de Lacaille first described the constellation as l'Horloge à pendule & à secondes (Clock with pendulum and seconds hand) in 1756, after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in previously uncharted regions of the southern celestial hemisphere, which were not visible from Europe. All but one honoured scientific instruments, and so symbolised the Age of Enlightenment. The constellation name was Latinised to Horologium in a catalogue and updated chart published posthumously in 1763.

Horologium constellation: showing the tangent line, or viewer's horizon, at latitude approx 23 N, which is parallel to the line of -67.04 declension, the lower declination boundary of the constellation. Covering a total of 248.9 square degrees or 0.603% of the sky, Horologium ranks 58th in area out of the 88 modern constellations. Its position in the southern celestial hemisphere means the whole constellation is visible to observers south of 23°N. Horologium is bordered by five constellations: Eridanus (the Po river), Caelum (the chisel), Reticulum (the reticle), Dorado (the dolphin/swordfish), and Hydrus (the male water snake).

Canis Minor is a small constellation in the northern celestial hemisphere. In the second century, it was included as an asterism, or pattern, of two stars in Ptolemy's 48 constellations, and it is counted among the 88 modern constellations. Its name is Latin for "lesser dog", in contrast to Canis Major, the "greater dog"; both figures are commonly represented as following the constellation of Orion the hunter. Canis Minor contains only two stars brighter than the fourth magnitude, Procyon (Alpha Canis Minoris), with a magnitude of 0.34, and Gomeisa (Beta Canis Minoris), with a magnitude of 2.9.

They worked on the first classification schemes for the ultraviolet spectrum They collaborated with Yvette Andrillat on stars in the near-infrared, and Carlos Jaschek had a long- term collaboration with the Marcel Golay group in Switzerland to make comparisons between photometry and spectroscopy. The Jascheks collaborated on Be, Ae, shell, Ap, and other peculiar stars. They produced a catalogue and bibliography of 2,000 Be stars for the period from 1950 to 1970 based on Mercedes Jaschek's survey of the Southern Celestial Hemisphere. They were the first to introduce the gallium stars subgroup and to discover the ApSi4200 stars.

NGC 2363 as seen by the Hubble Space Telescope. The luminous blue variable star NGC 2363-V1 is the isolated bright star above and left of center. (Credit NASA) In 1996, Robert was credited, along with two other astrophysicists, for the discovery of a new luminous blue variable star called NGC 2363-V1, which is located in the star-forming region NGC 2363, at the far southwestern part of the irregular galaxy called NGC 2366 in the Camelopardalis constellation, in the northern celestial hemisphere. It is almost 11 million light years away from the Earth's galaxy.

After its perihelion passage, the comet moved into the southern celestial hemisphere. The comet was much less impressive to southern hemisphere observers than it had been in the northern hemisphere, but southerners were able to see the comet gradually fade from view during the second half of 1997. The last naked-eye observations were reported in December 1997, which meant that the comet had remained visible without aid for 569 days, or about 18 and a half months. The previous record had been set by the Great Comet of 1811, which was visible to the naked eye for about 9 months.

The International Astronomical Union (IAU) defines the geographic north pole of a planet or any of its satellites in the Solar System as the planetary pole that is in the same celestial hemisphere, relative to the invariable plane of the Solar System, as Earth's north pole. This definition is independent of the object's direction of rotation about its axis. This implies that an object's direction of rotation, when viewed from above its north pole, may be either clockwise or counterclockwise. The direction of rotation exhibited by most objects in the solar system (including Sun and Earth) is counterclockwise.

The earliest predecessor of the YBS, titled Harvard Photometry, was published in 1884 by the Harvard College Observatory under the supervision of Edward Charles Pickering, and contained about 4,000 stars. Following its release, Pickering promoted a broader stellar survey for the southern celestial hemisphere, equally as thorough as the Harvard Photometry of 1884. This photometry work was carried out by Solon I. Bailey between 1889 and 1891, leading to the publication of the Revised Harvard Photometry in 1908. The new catalogue contained stars down to magnitude 6.5 in both hemispheres, for which John A. Parkhurst continued work through the 1920s.

Seen at the horizon, Phobos is about 0.14° wide; at zenith it is 0.20°, one-third as wide as the full Moon as seen from Earth. By comparison, the Sun has an apparent size of about 0.35° in the Martian sky. Phobos's phases, inasmuch as they can be observed from Mars, take 0.3191 days (Phobos's synodic period) to run their course, a mere 13 seconds longer than Phobos's sidereal period. As seen from Phobos, Mars would appear 6,400 times larger and 2,500 times brighter than the full Moon appears from Earth, taking up a quarter of the width of a celestial hemisphere.

Seen in the 1824 star chart set Urania's Mirror (in the lower right) Telescopium was introduced in 1751–52 by Nicolas-Louis de Lacaille with the French name le Telescope, depicting an aerial telescope, after he had observed and catalogued 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised 14 new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honored instruments that symbolised the Age of Enlightenment. Covering 40 degrees of the night sky, the telescope stretched out northwards between Sagittarius and Scorpius.

By revealing such large numbers of very young galaxies, the HDF has become a landmark image in the study of the early universe. Three years after the HDF observations were taken, a region in the south celestial hemisphere was imaged in a similar way and named the Hubble Deep Field South. The similarities between the two regions strengthened the belief that the universe is uniform over large scales and that the Earth occupies a typical region in the Universe (the cosmological principle). A wider but shallower survey was also made as part of the Great Observatories Origins Deep Survey.

The stars that comprise Microscopium are in a region previously considered the hind feet of Sagittarius, a neighbouring constellation. John Ellard Gore wrote that al-Sufi seems to have reported that Ptolemy had seen the stars but he (Al Sufi) did not pinpoint their positions. Microscopium itself was introduced in 1751–52 by Lacaille with the French name le Microscope, after he had observed and catalogued 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe.

The Corona Borealis Supercluster is a supercluster located in the constellation Corona Borealis and the most prominent example of its kind in the Northern Celestial Hemisphere. Dense and compact compared with other superclusters, its mass has been calculated to lie somewhere between 0.6 and 12 × 1016 solar masses (M⊙). It contains the galaxy clusters Abell 2056, Abell 2061, Abell 2065 (the most massive galaxy cluster within the supercluster), Abell 2067, Abell 2079, Abell 2089, and Abell 2092. Of these, Abell 2056, 2061, 2065, 2067 and A2089 are gravitationally bound and in the process of collapsing to form a massive cluster.

This star is very narrowly in the southern celestial hemisphere; this means that it can be observed from all the inhabited regions of the Earth without any difficulty and that it is invisible only far beyond the Arctic polar circle. It appears near or below the horizon, depending on season as circumpolar in innermost areas of the Antarctic continent. Being of magnitude 6.4, it is observable with the naked eye only in ideal conditions; it is easy to observe with a small pair of binoculars. The best period for the night-time observation of Orion in either hemisphere is between late October and April.

At the Earth's North Pole, the north celestial pole is directly overhead, and all stars that are visible at all (that is, all stars in the Northern Celestial Hemisphere) are circumpolar. As one travels south, the north celestial pole moves towards the northern horizon. More and more stars that are at a distance from it begin to disappear below the horizon for some portion of their daily "orbit", and the circle containing the remaining circumpolar stars becomes increasingly small. At the Equator, this circle vanishes to a single point – the celestial pole itself – which lies on the horizon, and there are thus effectively no circumpolar stars at all.

With an apparent visual magnitude of −0.05, Arcturus is the brightest star in the northern celestial hemisphere and the fourth-brightest star in the night sky, after Sirius (−1.46 apparent magnitude), Canopus (−0.72) and α Centauri (combined magnitude of −0.27). However, α Centauri AB is a binary star, whose components are both fainter than Arcturus. This makes Arcturus the third-brightest individual star, just ahead of α Centauri A (officially named Rigil Kentaurus), whose apparent magnitude . The French mathematician and astronomer Jean-Baptiste Morin observed Arcturus in the daytime with a telescope in 1635, a first for any star other than the Sun and supernovae.

Octans was one of 14 constellations created by French astronomer Nicolas Louis de Lacaille during his expedition to the Cape of Good Hope, and was originally named l’Octans de Reflexion (“the reflecting octant”) in 1752, after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment. It was part of his catalogue of the southern sky, the Coelum Australe Stelliferum, which was published posthumously in 1763.

The constellations Pavo and Indus, featured in the chart of the Southern Celestial Hemisphere by Johann Gabriel Doppelmayr in his Atlas Coelestis, c. 1742 Pavo (upper right), with the other southern birds, in its first appearance in a celestial atlas, Johann Bayer's Uranometria. Pavo was one of the twelve constellations established by Petrus Plancius from the observations of the southern sky by explorers Pieter Dirkszoon Keyser and Frederick de Houtman, who had sailed on the first Dutch trading expedition, known as the Eerste Schipvaart, to the East Indies. It first appeared on a 35-cm (14 in) diameter celestial globe published in 1598 in Amsterdam by Plancius with Jodocus Hondius.

In 1966, a search for Wolf-Rayet stars in the northern celestial hemisphere discovered seven new examples. One, designated as Stephenson 3, was classified as WC. It was later found to show unusual emission lines of highly ionised OVI. Because of the unusual oxygen lines, seen in only a handful of other stars, it was given the spectral type WC5pec in the Sixth Catalogue of Galactic Wolf-Rayet Stars. In 1981, described as a WC-OVI star, it was identified as being associated with the active star-forming region ON2, and then a heavily-obscured open cluster designated Berkeley 87, south of the red supergiant BC Cygni.

In early Mesopotamian art, the Bull of Heaven was closely associated with Inanna, the Sumerian goddess of sexual love, fertility, and warfare. One of the oldest depictions shows the bull standing before the goddess' standard; since it has 3 stars depicted on its back (the cuneiform sign for "star-constellation"), there is good reason to regard this as the constellation later known as Taurus. The same iconic representation of the Heavenly Bull was depicted in the Dendera zodiac, an Egyptian bas-relief carving in a ceiling that depicted the celestial hemisphere using a planisphere. In these ancient cultures, the orientation of the horns was portrayed as upward or backward.

In the context of astronomical discussions or writing about celestial cartography, this celestial hemisphere may also simply then be referred to as the Northern Hemisphere. For the purpose of celestial mapping, astronomers may conceive the sky as the inside of a sphere divided into two halves by the celestial equator. The Northern Sky or Northern Hemisphere is therefore the half of the celestial sphere that is north of the celestial equator. Even if this geocentric model is the ideal projection of the terrestrial equator onto the imaginary celestial sphere, the northern and southern celestial hemispheres is not to be confused with descriptions of the terrestrial hemispheres of Earth itself.

The star is in the northern celestial hemisphere, but close to the celestial equator; this means that it can be observed from all the inhabited regions of the Earth without difficulty and that it is not visible only in the innermost areas of Antarctica. It appears as circumpolar only far beyond the Arctic polar circle. Its brightness puts it at the limit of visibility to the naked eye, so to be observed without the aid of devices requires a clear, and preferably moonless, sky. The best period for observation in the evening sky is between late October and April from both hemispheres; in February (as at J2000) it is anti-posed from the sun.

Doppelmayr's map of the southern celestial hemisphere, ca. 1730 There had been significant buildings on this land since the reign of William I.John Timbs' Abbeys, Castles and Ancient Halls of England and Wales Greenwich Palace, on the site of the present-day Maritime Museum, was the birthplace of both Henry VIII and his daughters Mary I and Elizabeth I; the Tudors used Greenwich Castle, which stood on the hilltop that the Observatory presently occupies, as a hunting lodge. Greenwich Castle was reportedly a favourite place for Henry VIII to house his mistresses, so that he could easily travel from the Palace to see them. In 1676 Flamsteed's house on Greenwich hill was completed, the Royal astronomer's place of operation.

Abell 2744 galaxy clusterHubble Frontier Fields view (7 January 2014). The Abell catalog of rich clusters of galaxies is an all-sky catalog of 4,073 rich galaxy clusters of nominal redshift z ≤ 0.2. This catalog supplements a revision of George O. Abell's original "Northern Survey" of 1958, which had only 2,712 clusters, with a further 1,361 clustersthe "Southern Survey" of 1989, published after Abell's death by co-authors Harold G. Corwin and Ronald P. Olowin from those parts of the south celestial hemisphere that had been omitted from the earlier survey. The Abell catalog, and especially its clusters, are of interest to amateur astronomers as challenge objects to be viewed in dark locations on large aperture amateur telescopes.

The orbit of the Moon lies in a plane that is inclined about 5.14° with respect to the ecliptic plane. The line of intersection of these planes passes through the two points at which the Moon's orbit crosses the ecliptic plane: the ascending node, where the Moon enters the Northern Celestial Hemisphere, and the descending node, where the Moon moves into the Southern. The draconic or nodical month is the average interval between two successive transits of the Moon through the same node. Because of the torque exerted by the Sun's gravity on the angular momentum of the Earth-Moon system, the plane of the Moon's orbit gradually rotates westward, which means the nodes gradually rotate around Earth.

Eta Carinae and Carina Nebula in the constellation of Carina As a 4th-magnitude star, Eta Carinae is comfortably visible to the naked eye in all but the most light-polluted skies in inner city areas according to the Bortle scale. Its brightness has varied over a wide range, from the second- brightest star in the sky at one point in the 19th century to well below naked eye visibility. Its location at around 60°S in the far Southern Celestial Hemisphere means it cannot be seen by observers in Europe and much of North America. Located between Canopus and the Southern Cross, Eta Carinae is easily pinpointed as the brightest star within the large naked eye Carina Nebula.

Composite image in X-rays by Chandra X-ray Observatory (blue) and radiowaves by Australia Telescope Compact Array (red) showing two lobes and a jet of plasma emanating from Pictor A NGC 1705 is an irregular dwarf galaxy 17 million light-years from Earth. It is one of the most active star forming galaxies in the nearby universe, despite the fact that its rate of star formation peaked around 30 million years ago. Pictor A, around 485 million light-years away, is a double-lobed radio galaxy and a powerful source of radio waves in the Southern Celestial Hemisphere. From a supermassive black hole at its centre, a relativistic jet shoots out to an X-ray hot spot 800,000 light years away.

Johann Bode's depiction of Antlia as a double-cylinder air pump The French astronomer Nicolas-Louis de Lacaille first described the constellation in French as la Machine Pneumatique (the Pneumatic Machine) in 1751–52, commemorating the air pump invented by the French physicist Denis Papin. De Lacaille had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope, devising fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. He named all but one in honour of instruments that symbolised the Age of Enlightenment. Lacaille depicted Antlia as a single-cylinder vacuum pump used in Papin's initial experiments, while German astronomer Johann Bode chose the more advanced double-cylinder version.

The milky Way above the glaciology shelter, Dome C, winter 2005 Dome C is notable for its potential to be an extremely good astronomical observation site; the transparency of the Antarctic atmosphere allows stars to be observed, even when the Sun is at its highest possible elevation angle of 38°. The good viewing is due to very low infrared sky emission, extremely low humidity, a high percentage of cloud-free time, low atmospheric aerosol and dust content, and freedom from light pollution and background light other than auroras and moonlight. This location was a serious candidate for the ESO's E-ELT project. However, sky coverage is less than at lower latitude locations as northern celestial hemisphere objects never rise or are too low above the horizon.

Artistic rendition of the sculptor's studio, along with parts of the neighbouring constellations of Cetus and Machina Electrica, in Urania's Mirror (1825) The region to the south of Cetus and Aquarius had been named by Aratus in 270 BC as The Waters – an area of scattered faint stars with two brighter stars standing out. Professor of astronomy Bradley Schaefer has proposed that these stars were most likely Alpha and Delta Sculptoris. The French astronomer Nicolas-Louis de Lacaille first described the constellation in French as l'Atelier du Sculpteur (the sculptor's studio) in 1751–52, depicting a three-legged table with a carved head on it, and an artist's mallet and two chisels on a block of marble alongside it. De Lacaille had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope, devising fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe.