Chart for the whole sky in October Stars and planets in the October evening sky
Chart for the southern sky in October Interesting objects in the October southern sky
Chart for the western sky in October Interesting objects in the October western sky
Notes and Charts for other months
Jupiter is the brightest star-like object in the evening sky, appearing north of overhead soon after sunset Canopus is in the southeast moving up into the eastern sky. Vega sets on the opposite horizon. Crux, the Southern Cross and the Pointers are in the south-west. Midway down the western sky is orange Antares at the heart of Scorpius. The Scorpion's tail, a.k.a. the fish-hook of Maui, curls up the sky. The Milky Way spans the sky from north through west and into south. The Magellanic Clouds, nearby galaxies marked as LMC and SMC on the chart, are misty glows above Canopus.
Jupiter is north of overhead at dusk, shining with a steady golden light. Binoculars show the disk of Jupiter. A small telescope easily shows all four big moons and the parallel stripes in Jupiter's clouds. Jupiter is 11 times wider than the earth and 320 times heavier. It is 680 million km from us just now.
Canopus, the second brightest star, is in the southeast at dusk. It swings up into the eastern sky during the night. Canopus is a truly bright star: 13 000 times the sun's brightness and 300 light years away. On the opposite skyline is Vega, setting in the late evening. Vega is the 5th brightest star. It is 50 times brighter than the sun but dimmed by its distance of 25 light years.
In the southwest are 'The Pointers ', Beta and Alpha Centauri, making a vertical pair. They point down to Crux the Southern Cross. Alpha Centauri, the top Pointer and the brightest star in that area, is the closest naked eye star. It is 4.3 light years away. And it is a binary star: two sun-like stars orbiting each other in 80 years. A telescope magnifying 50x will split the pair. Beta Centauri, like most of the stars in Crux, is a blue giant star, very hot and very luminous, hundreds of light years away.
Midway down the western sky is the orange star Antares marking the heart of the Scorpion. The Scorpion's tail loops up the sky in the evening, making a back-to-front question mark with Antares being the dot. The curved tail is the 'fish-hook of Maui' in Maori star lore. Antares is a red giant star: 600 light years* away and 19 000 times brighter than the sun. Red giants are dying stars; wringing the last of the thermo-nuclear energy from their cores. Massive ones like Antares end in a spectacular supernova explosion. Antares is about 20 times heavier than the sun. It is expected to blow up in about two million years. Above and right of the Scorpion's tail is 'the teapot' made by the brightest stars of Sagittarius. It is upside down in our southern hemisphere view.
The Milky Way is brightest and broadest in Scorpius and Sagittarius. In a dark sky it can be traced down past the Pointers and Crux into the south. In the other direction, past Sagittarius, it tracks down the north sky to the left of Vega. From northern parts of New Zealand the star Deneb can be seen in the middle of the Milky Way in Cygnus the swan.
The Milky Way is our edgewise view of the galaxy, the pancake of billions of stars of which the sun is just one. The thick hub of the galaxy, 30 000 light years away, is in Sagittarius. The actual centre, with a black hole three or four million times the sun's mass, is hidden by dust clouds in space. Its direction is a little outside the Teapot's spout. The nearer 'interstellar' clouds appear as gaps and slots in the Milky Way. The dust and gas has come from old stars that have thrown much of their material back into space as they faded or blew up. New stars eventually condense from this stuff. A scan along the Milky Way with binoculars shows many clusters of new stars and some glowing clouds of left-over gas. There are many in Scorpius and Sagittarius and in the Carina region below Crux.
The Large and Small Clouds of Magellan, LMC and SMC, look like two misty patches of light in the south sky. They are galaxies like our Milky Way but much smaller. The Large Cloud is about 5% the mass of our Galaxy and the small one 3%. That is still many billions of stars in each. The LMC is around 160 000 light years way; the SMC around 200 000 l.y away. They are thought to be satellite galaxies of the Milky Way, taking two billion years to orbit
On moonless evenings in a dark rural sky the Zodiacal Light is visible in the west. At first glance it looks like late twilight. On closer inspection one sees a faint broad column of light passing through Libra. It is sunlight reflecting off meteoric dust in the plane of the solar system. The dust may be the remains of a big comet that disintegrated thousands of years ago.
The Large & Small Clouds of Magellan (LMC & 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. The LMC is about 160 000 light years away and the SMC 200 000 l.y away, both very close by for galaxies. (1 light year is about 10 000 billion km, 1013 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 near the SMC it is one-tenth the distance, 15 000 light years away and 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. Omega Centauri, right of the Pointers, is a
similar cluster around 17 000 light years away.
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 the 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 (in The Pot's handle in the summer sky) 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, in the eastern dawn sky, is the brightest star in the sky. The planets Venus and Jupiter are brighter.
Alpha Centauri, the brighter Pointer, 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 splits the pair. (A very faint and slightly closer star, Proxima Centauri, orbits a quarter of a light-year, or 15 000 Sun-earth distances, from the Alpha pair.)
Coalsack nebula 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 is a compact cluster of young luminous stars about 7000 light years away. The cluster formed less than 10 million years ago. It is best seen in a telescope. 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 η [Greek 'e'] Carinae. It is
estimated to be to be 60 times heavier than the sun and a million times brighter.
Dust clouds dim it. Eta Carinae 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 sky.
The Theta Carina cluster or Southern Pleiades is a cluster on the west end of the 'Diamond Cross'. It is also called the 'Five of Diamonds' cluster, the reason obvious when it viewed in a telescope. It is much fainter and smaller than the real Pleiades in Taurus but a nice sight in binoculars. The cluster is about 500 light years away and is around 10 million years old.
Orange Antares is the brightest star in the region. It marks the heart of Scorpius the Scorpion. The Scorpion is head-down, tail-up in the evening sky now. It sets in the southwest around midnight. Antares and the tail make a back-to-front question mark. In Maori star lore the tail is the fish-hook of Maui.
Anatares is a red-giant star, 600 light years away, 19 000 times brighter than the sun, and big enough to fill Earth's orbit. Its mass or weight is about 20 times that of the sun, so the star is mostly extremely thin gas spread around a hot dense core. Red giants are the last stage in the evolution of a star. The hot dense core of the star is wringing the last of the thermo-nuclear energy from helium to form heavier elements. For massive stars like Antares a core of iron (gas!) is finally formed. This leads to a collapse of the core into a neutron star or a black hole. In the resulting explosion -- a supernova -- chemical elements heavier than iron are made. The rich amount of heavy elements on earth shows that we are made of the matter that has been processed in two supernova explosions since the beginning of the universe.
This part of the Milky Way is broad and bright as we are looking to the centre of the galaxy. The actual centre, 27 000 light years away, is hidden from our view by intervening dust clouds. The nearer clouds make gaps and slots along the Milky Way. Some of the central bulge of the galaxy is glimpsed in gaps between the clouds, making brighter areas of Milky Way in this region. The dust is from old stars giving off clouds of gas rich in carbon (forming soot, roughly speaking) and silicon (making fine sand).
On the chart the direction to the centre of the galaxy is below the Teapot's spout and left of M8. Infrared telescopes, peering through the dust between us and the centre, show stars orbiting the invisible black hole at high speed. From the speed and orbits of these stars it is found that the central black hole is four million times heavier than the sun. Infra-red and x-ray 'flares' are seen from the region, as clouds of matter fall into the black hole. These confirm that the black hole is smaller than Earth's orbit, ruling out the possibility that the four million solar masses are just a dense cluster of stars.
At the right-angle bend in the Scorpion's tail is a large and bright cluster of stars, NGC 6231, looking like a small comet. It is around 6000 l.y. away. Its brightest stars are 60 000 times brighter than the sun. Right of the Scorpion's sting is M7 a cluster obvious to the eye and nicely seen in binoculars. M7 is about 800 l.y. away and around 220 million years old.
Below M7 and fainter is M6, the 'butterfly cluster' around 1600 l.y. away. Other clusters worth a look in binoculars are M23, NGC 6167, and NGC 6193. The 'M' objects were listed by the 18th Century French astronomer Charles Messier. He hunted comets, so made a catalogue of fuzzy objects that could be mistaken for comets. The NGC (New General Catalogue) are too far south to be seen from Paris.
Below Sagittarius's 'Teapot' is the glowing gas cloud M8, commonly called the 'Lagoon Nebula' from the dark lane of dust that crosses it. The gas is glowing in ultra-violet light from very hot stars. These stars have formed within the cloud in the past two million years. M8 is about 140 light years across and 5200 light years away. Nearby is M20, called the Trifid Nebula from its three-lobed appearance. M16 and other nebulae are also found in the area.
Globular clusters, spherical clusters of ancient stars, are found throughout the region. The brightest is M4 by Antares. It is also one of the closest at 7 000 l.y. away but is dimmed by a dust cloud between us and it. In binoculars and small telescopes globular clusters appear as round fuzzy spots. Others marked on the chart, with their distances in light years, are M10 (14 000 l.y.), M12 (19 000), M19 (27 000), M22 (10 000), M55 (20 000), M62 (22 000), M80 (30 000) and NGC 6541. The concentration of globular clusters in this area was an early clue that the centre of the galaxy lay in this direction and was along way from us.