Interesting object in the southern sky Chart for the southern sky in February
Interesting objects in the Northern Sky Chart for the northern sky in February
The brightest stars and Mars are mostly spread along a strip from the north, overhead and into the southeast sky. Orange Mars is low in the north at dusk with Orion above it and Taurus to its left. Sirius and Canopus are north and south of the zenith, respectively. Crux and the Pointers are in the southeast. Saturn and Regulus make a wide pair of 'stars' in the northeast sky.
Sirius is the first star to appear at dusk, north of overhead. Mars soon follows. Between these two, and a bit to the left, are Rigel and Betelgeuse, the brightest stars in Orion. Between these two is a line of three stars: Orion's belt. To southern hemisphere star watchers, the line of three makes the bottom of 'The Pot'. Orion's belt points down and left to a V-shaped pattern of stars making the face of Taurus the Bull. Left again, toward the northwest and lower, is the Pleiades or Matariki star cluster, also known as the Seven Sisters and Subaru. From northern New Zealand the bright star Capella is on the north skyline, below Marswhich is slowly fading as we leave it behind. It is 134 million km away at mid-month and very tiny in a telescope. Mars is half the diameter of Earth.
Sirius, 'the Dog Star', marks the head of Canis Major the big dog. A group of stars above and right of it make the dog's hindquarters and tail. Sirius is the brightest star in the sky both because it is relatively close, nine light years* away, and 23 times brighter than the sun. Procyon, in the northeast below Sirius, marks the smaller of the two dogs following Orion the hunter across the sky.
Rigel, directly above Orion's belt, is a bluish supergiant star, 40 000 times brighter than the sun and much hotter. It is 800 light years away. Orange Betelgeuse, below the line of three, is a red-giant star, cooler than the sun but hundreds of times bigger and 9 000 times brighter. It is 400 light years from us.
The V-shaped group making the face of Taurus the bull is called the Hyades cluster. It is 130 light years away. Orange Aldebaran, Arabic for 'the eye of the bull', is not a member of the cluster but on the line of sight, half the cluster's distance. The Pleiades/ Matariki Seven Sisters/ Subaru cluster, impressive in binoculars, is 400 light years from us.
Crux, the Southern Cross, is in the southeast. Below it are Beta and Alpha Centauri, often called 'The Pointers'. Alpha Centauri is the closest naked-eye star, 4.3 light years away. Beta Centauri, like most of the stars in Crux, is a blue-giant star hundreds of light years away. Canopus is also a very luminous distant star; 13 000 times brighter than the sun and 300 light years away.
The Milky Way is brightest in the southeast toward Crux. It can be traced up the sky, fading where it is nearly overhead. It becomes very faint east, right, of Orion. The Milky Way is our edgewise view of the galaxy, the pancake of billions of stars of which the sun is just one.
The Clouds of Magellan, LMC and SMC are high in the in the southwest sky, easily seen by eye on a dark moonless night. They are two small galaxies about 160 000 and 200 000 light years away.
Saturn is low in the northeast. The rings of Saturn and its largest moon, Titan, are visible in small telescopes. Binoculars show the planet and rings as a tiny oval. It is 1200 million km away.
In the dawn sky are Venus and Jupiter, later joined by Mercury. Venus is the brilliant 'morning star' rising in the southeast two hours before the sun. At the beginning of February Venus and Jupiter will make a striking close pair in the dawn twilight; Venus much brighter than golden Jupiter. Through the month Jupiter will climb higher in the dawn sky while Venus slips toward the sun. In the middle of the month Mercury will appear low in the southeast dawn. Jupiter, Venus and Mercury will then make a line of bright planets sloping into the southeast. Mercury climbs up the sky, passes Venus around the 26th and stops. The two planets stay low in the dawn sky through March.
To use the chart, hold it up to the sky. Turn the chart so the direction you are looking is at the bottom of the chart. If you are looking to the south then have 'South horizon' at the lower edge. As the earth turns the sky appears to rotate clockwise around the south celestial pole (SCP on the chart). Stars rise in the east and set in the west, just like the sun. The sky makes a small extra rotation from night to night as we orbit the sun.
Sirius is the brightest star in the evening sky, high in the east at dusk. Mars, orange coloured, is low in the north. Canopus, the second brightest star, is south of the zenith. Orion, containing 'The Pot', is midway up the north sky with Taurus and the Pleiades/Matariki toward the northwest. Saturn is low in the northeast, following Regulus across the sky. Crux, the Southern Cross, and the Pointers are midway up the southeast sky.
The Large & Small Clouds of Magellan (LMC and SMC) appear as two luminous patches, easily seen by eye in a dark sky. They are two galaxies like the Milky Way but much smaller. Each is made of billions of stars. The Large Cloud contains many clusters of young luminous stars seen as patches of light in binoculars and telescopes. Both clouds are about 160 000 light years away, very close by for galaxies. (1 light year is about 10 000 billion km.)
47 Tucanae,looks like a faint fuzzy star on the edge of the SMC. It is a globular cluster, a ball of millions of stars. A telescope is needed to see a peppering of stars around the edge of the cluster. Though it appears on the edge of the SMC it is one-tenth the distance, 15 000 light years away, and is has no connection to the Small Cloud. Globular clusters are mostly very old, 10 billion years or more; at least twice the age of the sun.
Tarantula nebula is a glowing gas cloud in the LMC. The gas glows in the ultra-violet light from a cluster of very hot stars at centre of the nebula. The cloud is about 800 light years across. It is easily seen in binoculars and can
be seen by eye on moonless nights.
This nebula is one of the brightest known. If it was as close as the Orion nebula then it would be as bright as the full moon.
Canopus is the second brightest star. It is 14 000 times brighter than the sun and 300 light years away. Sirius, low in the east on spring evenings, is the brightest star in the sky.
Alpha Centauri is the closest naked-eye star, 4.3 light-years away. Alpha Centauri is a binary star: two stars about the same size as the sun orbiting around each other in 80 years. A telescope that magnifies 30x shows the pair. (A very faint and slightly closer star, Proxima Centauri, probably orbits the Alpha pair.)
Omega Centauri is a globular cluster like 47 Tucanae but bigger. Its total mass is six million times the sun's. It is 17000 light years away and 200 light years across. Omega Centauri is the biggest globular cluster in our galaxy. It may have once been the core of a small galaxy that was captured by the Milky Way.
The Coalsack nebula, in Crux, is a cloud of dust and gas about 300 light years away, dimming the more distant stars in the Milky Way. Many similar 'dark nebulae' can be seen, appearing as slots and holes in the Milky Way. These clouds of dust and gas eventually coalesce into clusters of stars.
The Jewel Box also in Crux, is a compact cluster of young luminous stars about 7000 light years away. The cluster formed less than 10 million ago. To the eye it looks like a faint star.
Eta Carina
nebula is a glowing gas cloud about 8000 light
years away. The golden star in the cloud, visible in
binoculars, is Eta [Greek η] Carinae. It is estimated
to be to be 60 times heavier than the sun and a million
times brighter but is dimmed by dust clouds around it. It
is expected to explode as a supernova "soon", that is in
the next few thousand years.
Many star clusters are found in this part of the Milky Way.
Sirius and Mars are eye-catching objects in the north sky in February evenings: Sirius high up; Mars low down. Between them is Orion the Hunter marked by prominent Rigel and Betelgeuse with the well-known 'pot' or 'saucepan' pattern between them. Below and left of Orion is Taurus the Bull with Aldebaran being one of Taurus's eyes. The V-shaped Hyades cluster outlines the bull's head. (All these pictures were thought up by north hemisphere cultures so are upside down to us.) The Pleiades or Matariki star cluster rides on the Bull's back, left of Aldebaran and lower in the sky. Low in the northeast are Castor and Pollux marking the heads of Gemini the Twins. Right of them, rising later in the evening, is the Praesepe star cluster making the shell of Cancer the Crab.
The Pleiades / Seven Sisters / Matariki / Subaru, and many other names, is a cluster of stars well known in both hemispheres. Though often called the Seven Sisters, most modern eyes see only six stars. Dozens are visible in binoculars. The cluster is about 440 light years away. Its brightest stars are around 200 times brighter than the sun.
The Hyades cluster is 150 light years away. Its brightest stars (not Aldebaran!) are about 70 times brighter than the sun. Aldebaran is not a member of the cluster but simply on the line of sight. It is 65 l.y. away and 150 times brighter than the sun. Aldebaran is a giant star about 25 times bigger than the sun though only five times heavier. Its orange colour is due to its temperature, around 3500° C. The sun is 5500° C.
Orion, in the northern hemisphere view, has a shield raised toward Taurus and a club ready for action. The line of three stars makes Orion's Belt. The line of faint stars above the belt form Orion's Sword in the northern view, dangling from his belt. To most southern hemisphere sky watchers the belt and sword form The Pot, or the Saucepan.
The Orion Nebula is visible in binoculars as a misty glow around the middle stars of Orion's Sword or the handle of The Pot. It is a vast cloud of dust and gas about 1270 l.y. away and nearly 20 l.y. across. Ultra-violet light from a massive, extremely hot star in the cloud causes it to glow. Some stars in this region may be less than a million years old. The sun, by contrast, is 4.6 billion years old. Stars continue to form in a giant cloud behind the glowing nebula. There are many bright and dark nebulae in this region. The Horsehead nebula, a favourite of astronomy books, is beside the right-hand star of Orion's Belt, but too faint to be seen in small telescopes.
Sirius is the brightest star, though the planets Venus and Jupiter, and sometimes Mars, are brighter. Sirius appears bright because it is both brighter than the sun and relatively a close 8.6 l.y. away. Sirius was often called 'the dog star' being the brightest star in Canis Major, one of the two dogs that follow Orion across the sky. Rigel is a blue 'supergiant' star around 40,000 times brighter than the sun and 800 l.y. away. Its surface temperature is around 20,000°C, giving it a bluish colour.
Betelgeuse is a red giant star 250 times bigger than the sun -- wider than earth's orbit! -- but only around 20 times heavier. It is mostly very thin gas surrounding a hot dense core. It is around 10,000 times brighter than the sun, about 400 light years away, and has a surface temperature around 3000°.
Mars, though bright, is disappointing in a telescope. It is around 130 million km from us in February and shows only a tiny disc. The position shown is at mid-month; Mars is moving eastward (rightward) against the star background keeping it in the evening sky for most of this year.
