The stars in tonight’s sky form many familiar patterns that make their host constellations easy to identify.
Observers in the northern hemisphere can see the bright stars of spring – Arcturus and Spica – rising in the east and southeast. The winter stars Rigel, Betelgeuse, Aldebaran and Sirius set in the western and southwestern sky in the evening.
In the southern hemisphere, Sirius and Canopus – the brightest stars in Earth’s sky – appear high overhead. The bright stars of Orion, Taurus and Gemini appear in the northern and northwestern sky, while the Southern Pointers (Alpha and Beta Centauri) and the stars of the Southern Cross dominate the southeastern sky.
The stars visible tonight depend on the observer’s location and the time of night. The star maps below show the first and second magnitude stars visible in the night sky around 10 pm in the mid-northern, equatorial, and mid-southern latitudes.
Northern hemisphere
The bright stars of the constellations Leo, Gemini, Auriga, and Ursa Major appear high above the horizon around 10 pm.
Pollux and Castor, the brightest stars in Gemini, mark the heads of the celestial Twins. Castor can be found by extending a line from Rigel through Betelgeuse in Orion.
The brighter Pollux is part of the Winter Circle, a large asterism that keeps setting earlier as the winter season comes to an end. Other bright stars of the Winter Circle – Sirius in Canis Major, Procyon in Canis Minor, Rigel in Orion, Aldebaran in Taurus, and Capella in Auriga – are prominent in the western and southwestern sky.
Stars visible tonight in the northern hemisphere, image: Stellarium
Capella is part of a smaller hexagon formed by the brightest stars of Auriga (the Charioteer) with Elnath in the neighbouring Taurus (the Bull).
Regulus, the brightest star in Leo, appears at the base of the Sickle of Leo, a star pattern that outlines the Lion’s head. It also forms the Spring Triangle with Arcturus and Spica, the luminaries of Boötes and Virgo. The asterism is prominent in the evening sky throughout the spring months.
The brightest stars of Ursa Major (the Great Bear) form the Big Dipper, one of the most recognizable star patterns in the night sky. The seven stars – Alkaid, Mizar, Alioth, Megrez, Phecda, Dubhe, and Merak – appear overhead throughout the spring months.
Northern sky
The five brightest stars of Cassiopeia – Schedar, Caph, Gamma Cassiopeiae, Ruchbah, and Segin – dominate the northern and northwestern sky in the evening. They form Cassiopeia’s W, one of the brightest asterisms in the far northern sky.
A line drawn from Schedar through Caph leads to Alderamin, the brightest star in the fainter Cepheus. A line extended from Gamma Cassiopeiae through Ruchbah points in the direction of Mirfak, the lucida of Perseus.
Polaris and Kochab, the brightest stars in Ursa Minor (the Little Bear) appear high above the northern horizon. They form the Little Dipper with five fainter Ursa Minor stars. The asterism requires very clear, dark skies to be seen.
Polaris, the North Star, is the nearest visible star to the north celestial pole. It can be found by drawing a line from Merak through Dubhe in the brighter Big Dipper. The supergiant always appears in the same spot from any given location and stands out as the only bright star in this area of the sky.
Two relatively conspicuous asterisms rise in the northeastern sky in the evening. The Head of Draco is formed by Eltanin with Rastaban, Grumium and Kuma. Eltanin and Rastaban mark the Dragon’s eyes.
The Keystone, an asterism that represents the torso of Hercules, is formed by Pi, Eta, Zeta, and Epsilon Herculis. It appears in the region between Vega and Arcturus.
Stars in the northern sky tonight, image: Stellarium
Eastern sky
Arcturus, the brightest star in the northern celestial hemisphere, appears almost directly east around 10 pm. It is the brightest star in the constellation Boötes (the Herdsman) and the fourth brightest star in the sky, after Sirius, Canopus, and Alpha Centauri.
The evolved giant star appears at the base of the Kite, an asterism that dominates the Herdsman constellation. It can be found by following the curved line formed by the three stars of the Big Dipper’s handle, Alioth, Mizar and Alkaid.
Spica, the brightest star in Virgo and the 16th brightest star in the sky, appears further down the same line. The fast-spinning hot blue star appears at the base of the Y of Virgo, a relatively bright asterism that sits in the southeastern sky in the evening.
The brightest stars of Corvus (the Crow) form a quadrilateral asterism called Spica’s Spanker or the Sail. The northern side of the asterism points towards Spica.
Arcturus and Spica form Spring Triangle with Regulus in Leo. They also form the Diamond of Virgo (the Great Diamond) with the fainter Denebola in Leo and Cor Caroli in Canes Venatici.
The two spring asterisms appear high above the horizon during spring evenings for observers in the northern hemisphere. The variable star Cor Caroli is the brightest star in the region between Alkaid in Ursa Major and Denebola in Leo.
Stars in the eastern sky tonight, image: Stellarium
Western sky
The bright stars of the Winter Circle (the Winter Hexagon) dominate the western and southwestern sky around 10 pm. Formed by six first magnitude stars – Sirius, Procyon, Pollux, Capella, Aldebaran, and Rigel – the Winter Circle is one of the largest and brightest asterisms in the sky.
Sirius and Procyon form the smaller Winter Triangle with Betelgeuse. The asterism can be used to find the faint constellation Monoceros (the Unicorn), most of which lies within its borders.
Sirius and Aldebaran can be found using the three stars of Orion’s Belt, Alnitak, Alnilam and Mintaka. A line extended through the Belt leads to these bright stars.
The Orion’s Belt stars are part of the bright, hourglass-shaped constellation figure of Orion, the Hunter. The figure is also formed by Betelgeuse, Rigel, Bellatrix, and Saiph. Most of these stars will end their lives as brilliant supernovae.
Aldebaran, the brightest star in Taurus and the 14th brightest star in the sky, appears almost directly west in the evening. The giant star marks the Bull’s eye and lies in the same line of sight as the bright, large Hyades cluster. Ain (Epsilon Tauri), one of the brightest Hyades stars, marks the Bull’s other eye. Aldebaran and the V-shaped Hyades outline the Bull’s head.
Mirfak and Algol, the brightest stars in Perseus, stand out in the northwestern sky. The supergiant Mirfak is the brightest member of the Alpha Persei Cluster, an open star cluster visible to the unaided eye on a clear, dark night. The star and the cluster are part of the Segment of Perseus, a curving line of relatively bright stars in the region between Cassiopeia’s W and Auriga’s hexagon.
The famous variable star Algol marks the head of the Gorgon Medusa. It forms a triangle with Mirfak and Almach, the third brightest star of Andromeda.
Stars in the western sky tonight, image: Stellarium
Southern sky
The brightest star lying almost directly south is Alphard, the lucida of the constellation Hydra. Alphard appears relatively isolated in the sky, with no other exceptionally bright stars nearby. The giant star forms a triangle with the brighter Regulus in Leo and Procyon in Canis Minor.
Procyon, the eighth brightest star in the sky, forms the Winter Triangle with Sirius and Betelgeuse. As the winter season draws to a close, the asterism will keep setting earlier in the evening.
Sirius and Procyon are among our nearest neighbours. Sirius lies only 8.60 light-years away and Procyon, 11.46 light-years away.
Sirius and other bright stars of Canis Major are prominent above the southwestern horizon. The Dog Star is the only one of these that will not end its life as a supernova. Adhara, Wezen, Aludra, and Mirzam are all massive, distant stars that will have fiery ends, much like their bright Orion neighbours.
Stars in the southern sky tonight, image: Stellarium
Equatorial latitudes
For observers near the equator, Procyon and Regulus are the nearest first-magnitude stars to the zenith around 10 pm. Procyon is the brightest star in the constellation Canis Minor (the Little Dog) and the eighth brightest star in the sky and Regulus is the lucida of Leo and the 21st brightest star.
Regulus and Procyon can be used to identify the second magnitude Alphard, the brightest star in Hydra. Even though it is the largest of the 88 constellations, Hydra does not contain any other first or second magnitude stars.
Regulus is part of the Sickle, an asterism that represents the Lion’s head. Regulus itself marks the Lion’s heart. The beast’s tail is marked by Denebola.
Sirius, Canopus and Rigil Kentaurus, the three brightest stars in the sky, are visible in the evening. Sirius appears high in the western sky, Canopus lies in the southwest, and Rigil Kentaurus sits lower in the southeastern sky.
Arcturus and Capella, the fourth and sixth brightest stars, can be spotted above the northeastern and northwestern horizon.
Stars visible tonight in equatorial latitudes, image: Stellarium
Northern sky
The stars of Ursa Major (the Great Bear) dominate the northern sky and those of Auriga (the Charioteer) are prominent in the northwest.
Seven bright Ursa Major stars form the Big Dipper, an asterism that appears upside-down from the equatorial and southern latitudes. Five of the seven stars – Alioth, Mizar, Phecda, Megrez, and Merak – are members of the Ursa Major moving group, a stellar family that shares a common origin and motion through space.
Alkaid and Dubhe do not belong to the Ursa Major association. They lie over 100 light-years away, while the other stars are closer to us.
Capella, the sixth brightest star in the sky, forms Auriga’s hexagon with Menkalinan, Almaaz, Hassaleh and Mahasim in Auriga and Elnath in Taurus. The hexagon asterism can be used to find several bright open clusters in Auriga: Messier 36, Messier 37, and Messier 38.
Stars in the northern sky tonight in equatorial latitudes, image: Stellarium
Eastern sky
Arcturus and Spica, the fourth and 16th brightest stars in the sky, are the brightest stars in the eastern sky. Both stars can be found by following the curved line of the Big Dipper’s handle. An imaginary line extended from Alioth, Mizar and Alkaid first leads to Arcturus and then to Spica.
Arcturus and Spica are very different stars. Arcturus, the luminary of the constellation Boötes (the Herdsman) is an old K-type star on the red giant branch. It has a mass of 1.08 solar masses and has grown to a size of 25.4 solar radii as it evolved away from the main sequence. It is 170 times more luminous than the Sun. The red giant is much older than the Sun. It has an estimated age of 7.1 billion years. It lies only 36.7 light-years away.
Spica, on the other hand, is a very young, hot, blue, B-type giant or subgiant star located approximately 250 light-years away. With 11.43 times the Sun’s mass, the star is a supernova candidate. Even though it has only a fraction of Arcturus’ age – 12.5 million years – it has evolved much faster because of its high mass. The star has a radius 7.47 times that of the Sun and shines with 20,512 solar luminosities. Because of its fast spin rate – 165.3 km/s – it has an oblate shape, with flattening at the poles and a pronounced equatorial bulge.
Both Spica and Arcturus form constellation-based asterisms with fainter stars in their respective constellations. Arcturus appears at the base of the Kite, and Spica is at the base of the Y of Virgo.
Stars in the eastern sky tonight in equatorial latitudes, image: Stellarium
Western sky
The sky above the western horizon is packed with exceptionally bright stars in the evening. Sirius and Canopus, the brightest stars in the sky, are visible in the western and southwestern sky. Procyon in Canis Minor appears high above the western horizon, and Pollux and Castor in Gemini are high in the northwestern sky.
The bright stars of Orion – Rigel, Betelgeuse, Bellatrix, Saiph, Alnitak, Alnilam, and Mintaka – outline the Hunter’s hourglass constellation figure, which appears perpendicular to the western horizon around 10 pm. A line drawn through the Orion’s Belt stars leads towards Sirius.
Sirius, Procyon and Betelgeuse form a conspicuous triangle that dominates the western sky. The faint constellation Monoceros, the home of the Rosette and Cone nebulae, appears within the triangle.
Rigel and Saiph, the supergiants that mark Orion’s knees (or feet) can be used to locate the relatively bright stars of Lepus (the Hare). The Hare’s ears appear near Rigel and its tail near Saiph.
Stars in the western sky tonight in equatorial latitudes, image: Stellarium
Southern sky
The bright stars of Centaurus and Crux dominate the southern and southeastern sky, while the constellations that used to form Argo Navis (the Ship Argo) – Carina (the Keel), Puppis (the Stern), and Vela (the Sails) – appear higher in the western and southwestern sky.
Rigil Kentaurus and Hadar (Alpha and Beta Centauri) are the third and 11th brightest stars in the sky. Alpha Centauri is the nearest star system to Earth. It lies only 4.344 light-years away. The faintest star in the system, the red dwarf Proxima Centauri, is the closest individual star to the Sun.
Beta Centauri is also a triple star system, but one that is much hotter and more luminous than Alpha Centauri. Hadar, the primary component, is a variable blue giant located 361 light-years away. It is 31,600 times more luminous than the Sun. Like its close neighbour, Beta Centauri Ab, it is a supernova candidate. It has a mass 12.02 times that of the Sun.
Alpha and Beta Centauri are called the Southern Pointers. They point in the direction of Gacrux, the star at the top of the Southern Cross.
The Southern Cross is formed by Acrux, Mimosa, Gacrux, Imai and Ginan. It is one of the most familiar features of the far southern sky. The asterism can be used to find the south celestial pole. A line extended from Gacrux through Acrux passes close to Sigma Octantis, the nearest visible star to the pole.
Canopus, the luminary of Carina and the second brightest star in the sky, is the brightest point of light above the southwestern horizon in the evening. It is one of three bright Carina stars that were selected for use in the field of celestial navigation. The other two are Miaplacidus and Avior.
Miaplacidus and Avior are both part of diamond-shaped asterisms that appear similar to the Southern Cross. Avior forms the False Cross with Aspidiske in Carina and Alsephina and Markeb in Vela, and Miaplacidus forms the Diamond Cross with Theta, Upsilon and Omega Carinae. Both asterisms are fainter than the true Southern Cross.
Stars in the southern sky tonight in equatorial latitudes, image: Stellarium
Southern hemisphere
Sirius and Canopus, the brightest stars in the sky, appear high overhead in the evening for observers in the southern hemisphere. Sirius is the brightest star in the constellation Canis Major (the Great Dog) and Canopus is the luminary of Carina (the Keel).
Rigil Kentaurus, the third brightest star, appears high above the southeastern horizon. The lucida of the constellation Centaurus is part of the nearest star system to the Sun.
Other bright stars that appear close to the zenith around 10 pm include those in the constellations Puppis (Naos), Vela (Regor, Alsephina, Suhail, and Markeb), and Carina (Miaplacidus, Avior, and Aspidiske).
Stars visible tonight in the southern hemisphere, image: Stellarium
Northern sky
Pollux and Castor, the 17th and 23rd brightest stars in the sky, are the brightest points of light above the northern horizon. The stars mark the heads of the mythical twins represented by the constellation Gemini.
The brighter Pollux is a red clump giant located 33.78 light years away. Castor is the primary component in a sextuple star system 49.15 light-years away. Both stars have about twice the Sun’s mass and are much younger than the Sun.
Procyon, the lucida of Canis Minor (the Smaller Dog) and the eighth brightest star in the sky, appears higher above the horizon in the evening. It lies only 11.46 light years away and shines with about 7 solar luminosities. Like the brighter Sirius, it has a white dwarf companion.
The stars of Taurus (the Bull) and Auriga (the Charioteer) appear lower in the northwestern sky. Elnath, the star thar marks the Bull’s northern horn, is part of Auriga’s hexagon, an asterism that has partly set by 10 pm. The bright Capella, the luminary of Auriga and the sixth brightest star in the sky, sets earlier in the evening.
Regulus, the star that marks the heart of the Lion (Leo), is the brightest star in the northeastern sky. It is part of the Sickle, an asterism that appears upside down from the southern hemisphere. The Sickle represents the Lion’s head and mane. Denebola at the Lion’s tail appears more to the east.
Stars in the northern sky tonight in the southern hemisphere, image: Stellarium
Eastern sky
The brightest star in the eastern sky is Spica, the luminary of Virgo. Spica is part of a relatively bright asterism that looks like a crooked Y and extends in the direction of the constellations Leo and Coma Berenices.
The quadrilateral pattern visible above Spica in the evening is called the Sail or Spica’s Spanker. It is formed by Gienah, Kraz, Algorab and Minkar, the brightest stars in the constellation Corvus (the Crow). The northern side of the asterism points towards Spica.
Menkent, the northernmost bright star in Centaurus, appears in the southeastern sky. It marks the Centaur’s shoulder.
Stars in the eastern sky tonight in the southern hemisphere, image: Stellarium
Western sky
The sky directly west is devoid of any first or second magnitude stars. The faint constellation Eridanus (the River) occupies most of it. Its brightest star, the massive blue main sequence star Achernar, is the ninth brightest star in the sky. The fast-spinning star marks the River’s southern end and appears high above the southwestern horizon.
The fainter Cursa, the second brightest star in Eridanus, appears at the River’s northern end, next to Rigel in Orion.
The bright stars of Orion and Taurus dominate the northwestern sky. Aldebaran, the Bull’s eye, appears in the same line of sight as the Hyades, the nearest open cluster to Earth. The giant star forms the V-shaped Bull’s head with the brightest Hyades stars. It can be found by following the line formed by the three stars of Orion’s Belt, Alnitak, Alnilam, and Mintaka.
The seven brightest Orion stars appear high in the northwest. Most of them, including the blue supergiant Rigel and red supergiant Betelgeuse, are massive stars that will go out as supernovae when they reach the end of their evolutionary cycle.
Rigel and Betelgeuse are the seventh and tenth brightest stars in the sky. They are the brightest examples of their respective classes.
Stars in the western sky tonight in the southern hemisphere, image: Stellarium
Southern sky
There are five first magnitude stars in the southeastern and southwestern sky, but none directly south. The second magnitude Peacock, the brightest star in the constellation Pavo, appears very low above the southern horizon and may or may not be visible, depending on the location and geography.
Atria, the brightest star in Triangulum Australe, lies higher to the southeast. It forms a prominent triangle with Beta and Gamma Trianguli Australis.
The Southern Pointers, Alpha and Beta Centauri (Rigil Kentaurus and Hadar), and the stars of the Southern Cross appear high in the southeastern sky. Alpha and Beta Centauri point towards Gacrux, the star at the top of the Southern Cross. Gacrux forms the asterism with the brighter Acrux and Mimosa and the fainter Imai and Ginan. A line drawn through the long axis of the Southern Cross points in the general direction of the southern celestial pole.
Achernar, the lucida of Eridanus (the River), is prominent above the southwestern horizon. Shining at magnitude 0.40 – 0.46, it is the ninth brightest star in the sky, slightly outshining Hadar.
Achernar is an unusually fast spinner. It has a projected rotational velocity of 250 km/s. As a result, it has an oblate shape. Its diameter at the equator is 35% greater than its polar diameter, making Achernar the least spherical star in the Milky Way galaxy.
Achernar and Hadar can be used to locate the southern celestial pole, which lies in the faint constellation Octans, roughly halfway between the two bright stars. The South Star, Sigma Octantis, has an apparent magnitude of 5.47 and is barely visible even in the best of conditions. For this reason, the bright stars of Centaurus, Crux and Eridanus are more commonly used to locate the pole.
Stars in the southern sky tonight in the southern hemisphere, image: Stellarium