The International Astronomical Union (IAU) designates 88 constellations. [1] In the table below, they are listed by geographical visibility according to latitude as seen from Earth, as well as the best months for viewing the constellations at 21:00 (9 p.m.).
| Geographical visibility | Celestial coordinates | ||||||
|---|---|---|---|---|---|---|---|
| Abbrev. | Constellation | Northern- most latitude | Southern- most latitude | Month for best visibility at 21:00 (9 p.m.) | Right ascension (hours & mins) [2] | Declination (degs & mins) [3] | Quad [4] |
| UMi | Ursa Minor | 90 | -10 | June | +15 00.00 | +77 41.99 | NQ3 |
| Cep | Cepheus | 90 | -10 | November | +02 32.64 | +71 00.51 | NQ4 |
| Cam | Camelopardalis | 90 | -10 | February | +08 51.37 | +69 22.89 | NQ2 |
| Dra | Draco | 90 | -15 | July | +15 08.64 | +67 00.40 | NQ3 |
| Cas | Cassiopeia | 90 | -20 | November | +01 19.16 | +62 11.04 | NQ1 |
| UMa | Ursa Major | 90 | -30 | April | +11 18.76 | +50 43.27 | NQ2 |
| Lyn | Lynx | 90 | -55 | March | +07 59.53 | +47 28.00 | NQ2 |
| Lac | Lacerta | 90 | -40 | October | +22 27.68 | +46 02.51 | NQ4 |
| Per | Perseus | 90 | -35 | December | +03 10.50 | +45 00.79 | NQ1 |
| Cyg | Cygnus | 90 | -40 | September | +20 35.28 | +44 32.70 | NQ4 |
| Aur | Auriga | 90 | -40 | late February to early March | +06 04.42 | +42 01.68 | NQ2 |
| CVn | Canes Venatici | 90 | -40 | May | +13 06.96 | +40 06.11 | NQ3 |
| And | Andromeda | 90 | -40 | November | +00 48.46 | +37 25.91 | NQ1 |
| Lyr | Lyra | 90 | -40 | August | +18 51.17 | +36 41.36 | NQ4 |
| CrB | Corona Borealis | 90 | -50 | July | +15 50.59 | +32 37.49 | NQ3 |
| LMi | Leo Minor | 90 | -45 | April | +10 14.72 | +32 08.08 | NQ2 |
| Tri | Triangulum | 90 | -60 | December | +02 11.07 | +31 28.56 | NQ1 |
| Boo | Boötes | 90 | -50 | June | +14 42.64 | +31 12.16 | NQ3 |
| Her | Hercules | 90 | -50 | July | +17 23.16 | +27 29.93 | NQ3 |
| Vul | Vulpecula | 90 | -55 | September | +20 13.88 | +24 26.56 | NQ4 |
| Com | Coma Berenices | 90 | -70 | May | +12 47.27 | +23 18.34 | NQ3 |
| Gem | Gemini | 90 | -60 | February | +07 04.24 | +22 36.01 | NQ2 |
| Ari | Aries | 90 | -60 | December | +02 38.16 | +20 47.54 | NQ1 |
| Cnc | Cancer | 90 | -60 | March | +08 38.96 | +19 48.35 | NQ2 |
| Peg | Pegasus | 90 | -60 | October | +22 41.84 | +19 27.98 | NQ4 |
| Sge | Sagitta | 90 | -70 | August | +19 39.05 | +18 51.68 | NQ4 |
| Tau | Taurus | 90 | -65 | January | +04 42.13 | +14 52.63 | NQ1 |
| Psc | Pisces | 90 | -65 | November | +00 28.97 | +13 41.23 | NQ1 |
| Leo | Leo | 90 | -65 | April | +10 40.03 | +13 08.32 | NQ2 |
| Del | Delphinus | 90 | -69 | September | +20 41.61 | +11 40.26 | NQ4 |
| Equ | Equuleus | 90 | -80 | September | +21 11.26 | +07 45.49 | NQ4 |
| CMi | Canis Minor | 90 | -75 | March | +07 39.17 | +06 25.63 | NQ2 |
| Ser | Serpens [5] | 80 | -80 | July | +16 57.04 | +06 07.32 | NQ3 |
| Ori | Orion | 85 | -75 | January | +05 34.59 | +05 56.94 | NQ1 |
| Aql | Aquila | 90 | -75 | August | +19 40.02 | +03 24.65 | NQ4 |
| Mon | Monoceros | 75 | -90 | February | +07 03.63 | +00 16.93 | NQ2 |
| Sex | Sextans | 80 | -90 | April | +10 16.29 | −02 36.88 | SQ2 |
| Vir | Virgo | 80 | -80 | May | +13 24.39 | −04 09.51 | SQ3 |
| Cet | Cetus | 70 | -90 | November | +01 40.10 | −07 10.76 | SQ1 |
| Oph | Ophiuchus | 80 | -80 | July | +17 23.69 | −07 54.74 | SQ3 |
| Sct | Scutum | 80 | -90 | August | +18 40.39 | −09 53.32 | SQ4 |
| Aqr | Aquarius | 65 | -90 | October | +22 17.38 | −10 47.35 | SQ4 |
| Hya | Hydra | 54 | -83 | April | +11 36.73 | −14 31.91 | SQ2 |
| Lib | Libra | 65 | -90 | June | +15 11.96 | −15 14.08 | SQ3 |
| Crt | Crater | 65 | -90 | April | +11 23.75 | −15 55.74 | SQ2 |
| Cap | Capricornus | 60 | -90 | September | +21 02.93 | −18 01.39 | SQ4 |
| Crv | Corvus | 60 | -90 | May | +12 26.52 | −18 26.20 | SQ3 |
| Lep | Lepus | 63 | -90 | January | +05 33.95 | −19 02.78 | SQ1 |
| CMa | Canis Major | 60 | -90 | February | +06 49.74 | −22 08.42 | SQ2 |
| Sco | Scorpius | 40 | -90 | July | +16 53.24 | −27 01.89 | SQ3 |
| Pyx | Pyxis | 50 | -90 | March | +08 57.16 | −27 21.10 | SQ2 |
| Sgr | Sagittarius | 55 | -90 | August | +19 05.94 | −28 28.61 | SQ4 |
| Eri | Eridanus | 32 | -90 | December | +03 18.02 | −28 45.37 | SQ1 |
| PsA | Piscis Austrinus | 55 | -90 | October | +22 17.07 | −30 38.53 | SQ4 |
| Pup | Puppis | 40 | -90 | February | +07 15.48 | −31 10.64 | SQ2 |
| For | Fornax | 50 | -90 | December | +02 47.88 | −31 38.07 | SQ1 |
| Scl | Sculptor | 50 | -90 | November | +00 26.28 | −32 05.30 | SQ1 |
| Ant | Antlia | 45 | -90 | April | +10 16.43 | −32 29.01 | SQ2 |
| Col | Columba | 45 | -90 | February | +05 51.76 | −35 05.67 | SQ1 |
| Mic | Microscopium | 45 | -90 | September | +20 57.88 | −36 16.49 | SQ4 |
| Cae | Caelum | 40 | -90 | January | +04 42.27 | −37 52.90 | SQ1 |
| CrA | Corona Australis | 40 | -90 | August | +18 38.79 | −41 08.85 | SQ4 |
| Lup | Lupus | 35 | -90 | June | +15 13.21 | −42 42.53 | SQ3 |
| Gru | Grus | 34 | -90 | October | +22 27.39 | −46 21.11 | SQ4 |
| Vel | Vela | 30 | -90 | March | +09 34.64 | −47 10.03 | SQ2 |
| Cen | Centaurus | 25 | -90 | May | +13 04.27 | −47 20.72 | SQ3 |
| Phe | Phoenix | 32 | -90 | November | +00 55.91 | −48 34.84 | SQ1 |
| Tel | Telescopium | 40 | -90 | August | +19 19.54 | −51 02.21 | SQ4 |
| Nor | Norma | 30 | -90 | July | +15 54.18 | −51 21.09 | SQ3 |
| Hor | Horologium | 30 | -90 | December | +03 16.56 | −53 20.18 | SQ1 |
| Pic | Pictor | 26 | -90 | January | +05 42.46 | −53 28.45 | SQ1 |
| Ara | Ara | 25 | -90 | July | +17 22.49 | −56 35.30 | SQ3 |
| Dor | Dorado | 20 | -90 | January | +05 14.51 | −59 23.22 | SQ1 |
| Ind | Indus | 15 | -90 | September | +21 58.33 | −59 42.40 | SQ4 |
| Ret | Reticulum | 23 | -90 | January | +03 55.27 | −59 59.85 | SQ1 |
| Cru | Crux | 20 | -90 | May | +12 26.99 | −60 11.19 | SQ3 |
| Cir | Circinus | 30 | -90 | July | +14 34.54 | −63 01.82 | SQ3 |
| Car | Carina | 20 | -90 | March | +08 41.70 | −63 13.16 | SQ2 |
| TrA | Triangulum Australe | 25 | -90 | July | +16 04.95 | −65 23.28 | SQ3 |
| Pav | Pavo | 30 | -90 | August | +19 36.71 | −65 46.89 | SQ4 |
| Tuc | Tucana | 25 | -90 | November | +23 46.64 | −65 49.80 | SQ4 |
| Vol | Volans | 15 | -90 | March | +07 47.73 | −69 48.07 | SQ2 |
| Hyi | Hydrus | 8 | -90 | November | +02 20.65 | −69 57.39 | SQ1 |
| Mus | Musca | 10 | -90 | May | +12 35.28 | −70 09.66 | SQ3 |
| Aps | Apus | 5 | -90 | July | +16 08.65 | −75 18.00 | SQ3 |
| Men | Mensa | 4 | -90 | January | +05 24.90 | −77 30.24 | SQ1 |
| Cha | Chamaeleon | 5 | -90 | April | +10 41.53 | −79 12.30 | SQ2 |
| Oct | Octans | 0 | -90 | October | +23 00.00 | −82 09.12 | SQ4 |
A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England. They are named for John Flamsteed who first used them while compiling his Historia Coelestis Britannica.
Right ascension is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the point in question above the Earth. When paired with declination, these astronomical coordinates specify the location of a point on the celestial sphere in the equatorial coordinate system.
Serpens is a constellation in the northern celestial hemisphere. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations designated by the International Astronomical Union. It is unique among the modern constellations in being split into two non-contiguous parts, Serpens Caput to the west and Serpens Cauda to the east. Between these two halves lies the constellation of Ophiuchus, the "Serpent-Bearer". In figurative representations, the body of the serpent is represented as passing behind Ophiuchus between Mu Serpentis in Serpens Caput and Nu Serpentis in Serpens Cauda.
The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way Galaxy, and the fundamental plane parallel to an approximation of the galactic plane but offset to its north. It uses the right-handed convention, meaning that coordinates are positive toward the north and toward the east in the fundamental plane.
The International Astronomical Union (IAU) designates 88 constellations of stars. In the table below, they are ranked by the solid angle that they subtend in the sky, measured in square degrees and millisteradians.
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit.
Volans is a constellation in the southern sky. It represents a flying fish; its name is a shortened form of its original name, Piscis Volans. Volans was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm (14") diameter celestial globe published in 1597 in Amsterdam by Plancius with Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603.
In contemporary astronomy, 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky bordered by arcs of right ascension and declination, together covering the entire celestial sphere. Their boundaries were officially adopted by the International Astronomical Union in 1928 and published in 1930.
All stars but one can be associated with an IAU constellation. IAU constellations are areas of the sky. Although there are only 88 IAU constellations, the sky is actually divided into 89 irregularly shaped boxes as the constellation Serpens is split into two separate sections, Serpens Caput to the west and Serpens Cauda to the east.
The Carina–Sagittarius Arm is generally thought to be a minor spiral arm of the Milky Way galaxy. Each spiral arm is a long, diffuse curving streamer of stars that radiates from the Galactic Center. These gigantic structures are often composed of billions of stars and thousands of gas clouds. The Carina–Sagittarius Arm is one of the most pronounced arms in our galaxy as many HII regions, young stars and giant molecular clouds are concentrated in it.
Quadrans Muralis was a constellation created by the French astronomer Jérôme Lalande in 1795. It depicted a wall-mounted quadrant with which he and his nephew Michel Lefrançois de Lalande had charted the celestial sphere, and was named Le Mural in the French atlas. It was between the constellations of Boötes and Draco, near the tail of Ursa Major, containing stars between β Bootis (Nekkar) and η Ursae Majoris (Alkaid).
Alpha Serpentis or α Serpentis, formally named Unukalhai, is a double star in the head of the equatorial constellation of Serpens. With an apparent visual magnitude of 2.6, this star is the brightest in the constellation and it can be viewed with the naked eye from most of the Earth. Parallax measurements yield an estimated distance of about 74 light-years from the Sun.
Theta Serpentis is a triple star system in the constellation of Serpens.
Grzegorz Pojmański, is a Polish astronomer and professor at the Warsaw University Astronomical Observatory, Poland. In 1997 Pojmański together with professor Bohdan Paczyński implemented the project All Sky Automated Survey (ASAS). With the ASAS Alert System Pojmański discovered two new comets: C/2004 R2 (ASAS) and C/2006 A1 (Pojmański). Pojmański connects with the ASAS automatic telescope located in Las Campanas Observatory, Chile, via Internet.
The All Sky Automated Survey (ASAS) is a Polish project implemented on 7 April 1997 to do photometric monitoring of approximately 20 million stars brighter than 14 magnitude all over the sky. The automatic telescopes discovered two new comets in 2004 and 2006. The ASAS-South, located in Chile and ASAS-North, located in Hawai'i, are managed by Grzegorz Pojmański of the Warsaw University Observatory via the internet.
HD 175541 is an 8th magnitude star with an exoplanetary companion in the constellation Serpens. It has the proper name Kaveh, which was selected by Iran during the NameExoWorlds campaign as part of the 100th anniversary of the IAU. Kaveh is one of the heroes of Shahnameh. The apparent visual magnitude of 8.02 is too faint for this star to be visible in the naked eye. It is located at a distance of approximately 424 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +20 km/s. Despite its distance, it was given the number 736 in the Gliese Catalogue of Nearby Stars.
Sh2-54 is an extended bright nebula in the constellation of Serpens.
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.
