The Night Sky’s Two Brightest Stars

Sirius, Canopus & Gum Nebula (35mm 5DII)

The two brightest stars in the night sky shine in the southern sky.

Here are Sirius (at right) and Canopus (at bottom left), the brightest and second brightest stars in the night sky, together near the southern Milky Way.

My image also captures the huge loops of the Gum Nebula, thought to be the remains of a supernova that blew up a million years ago. It’s utterly invisible to the naked eye, but Sirius and Canopus stand out as brilliant stars even from light polluted sites.

Sirius can be seen from northern latitudes but Canopus is below the horizon for any location north of 37° North or so. I shot this image from Australia where these stars pass overhead.

Sirius is a hot blue-white star 8.6 light years away. Canopus appears slightly dimmer but only because it lies much farther away, at some 310 light years. In reality it is a supergiant yellow-white star that shines with a luminosity 15,000 times that of our Sun.

Canopus to Carina with LMC (35mm 5DII)

This image takes in Canopus at bottom right, next to the Large Magellanic Cloud, and with the southern Milky Way sweeping across the top, with the Carina Nebula and its attendant star clusters at top left and parts of the Gum Nebula at right.

Here are a few cocktail party facts about Canopus:

• In 480,000 years its motion around the Galaxy will bring Canopus close enough to Earth that it will become the brightest star in our night sky, outranking Sirius.

• The origin of its name is a mystery. One idea is that the star is named for the pilot of the ship that took Menelaus to Troy on the quest to re-capture Helen.

• Canopus, the star, was used in ancient times as a key navigation star for those sailing to southern seas, as it would have risen above the southern horizon from latitudes below 35° North back around 2000 BCE.

• Today, Canopus is charted as the brightest star in the constellation of Carina the Keel, part of the ancient constellation of Argo Navis, named for the ship sailed by Jason and the Argonauts.

— Alan, April 27, 2014 / © 2014 Alan Dyer


The Milky Way from Down Under

15mm Ultrawide Southern Milky Way (March 2014)

The Milky Way of the southern hemisphere arches across the sky from the Southern Cross to Orion.

I’ve arrived at my dark sky site near Coonabarabran, Australia, with a very clear night to start my two-week session under the southern stars. Tonight I had just a 2-hour window between end of twilight and moonrise. But I made good use of it by taking some ultra-wide-angle views of the Milky Way we never see from up north.

This horizon-to-horizon scene looks straight up and stretches from the Southern Cross at far left (in the east) through Vela and Puppis to Orion at right (in the west). This sweep includes much of the Milky Way forever below our horizon from northern latitudes. At centre is the wide loop of the Gum Nebula. At lower left is the Large Magellanic Cloud, a satellite galaxy of the Milky Way.

At upper right is Jupiter in Gemini. The two bright stars near the centre are Canopus (left of centre) and Sirius (right of centre).

This is a stack of five 5-minute exposures at f/4 with the 15mm full-frame fish-eye lens on the Canon 5D MkII at ISO 1000. The camera was on the iOptron Skytracker, its first time in the southern hemisphere and my first time aligning it on the South Celestial Pole. It took a few minutes but I got it! The tracker worked great.

The forecast is for clouds and rain the next few days. But I’m here for over two weeks, and the weather can’t be any worse than it was in 2010 when the area was flooding. So with luck there will be more images to come from down under.

– Alan, March 21, 2014 / © 2014 Alan Dyer

Ultrawide Southern Sky

Ultrawide Angle Southern Milky Way - December 2012

This horizon-to-horizon image takes in a broad sweep of the southern Milky Way from Orion to the Southern Cross.

At upper left shines bright Jupiter in Taurus and the stars of Orion, upside down. To the right of Orion is Sirius in Canis Major, the brightest star in the night sky. To the right of Sirius above the Milky Way is Canopus, the second brightest star in the night sky and one we don’t see from up north. The two satellite galaxy Magellanic Clouds are at upper right. Below them is the bright Milky Way through Carina and Crux, the Southern Cross. Alpha and Beta Centauri are just above the dark trees at right. This is the entire Milky Way you see on an early austral summer night from down under.

What stands out is the huge red bubble of gas called the Gum Nebula in Vela and Carina. It is strictly a photographic object but shows up well on red-sensitive digital cameras.

I shot this with a filter-modified Canon 5D Mark II camera and a 15mm wide-angle lens on a mount tracking the stars. It is a stack of four 6-minute exposures, shot from Australia a few nights ago under nearly perfect sky conditions.

– Alan, December 17, 2012 / © 2012 Alan Dyer


Sailing Toward Orion

Sailing Toward Orion

Not so long ago sailors used the Moon, Jupiter and the stars to chart their course on Earth. All are in this moonlit seascape.

I took this shot on November 27, as we set sail toward Hook Passage in the Whitsunday Islands, Queensland, Australia. The ship is the Solway Lass, a 110-year-old sailing ship that is now the oldest commercial ship plying the waters around Australia. It has been modernized and refitted, and at night runs with engines, not sails. And today, of course, GPS keeps the skipper informed of where the ship is. But before GPS and radio navigation, sailors used the sky to determine where on Earth they were.

Sextant sightings of the Sun and stars could give them their latitude and longitude. One star often used was Canopus, visible at far right in this image. Canopus has long been associated with the sea. It is the brightest star in Carina the Keel, once part of the sprawling constellation Argo Navis, the ship in the Greek legend of Jason and the Argonauts. Today, Canopus is still sighted by robot spacecraft bound for the planets to help them determine their position in the solar system.

Sirius and the stars of Orion (lying on his side here at a latitude of 20° South) appear through the rigging. At upper left is the bright glow of the nearly Full Moon, near the star Aldebaran and the Hyades star cluster.

Before the acceptance in the late 1700s of the chronometer as an accurate time-keeping device, the position of the Moon near bright stars served as an astronomical clock in the sky to provide sailors with local time. Another source of time (more for land-based navigators) was the changing positions of the moons of Jupiter — Jupiter is the bright star-like object at left.

I just finished a superb 6 days of sailing around the Whitsundays and will have 2 or 3 more sea-bound posts from this wonderful area of the world.

– Alan, November 30, 2012 / © 2012 Alan Dyer


On the Beach — Stargazing

This is stargazing in the tropics — on the beach, in shorts and sandals.

Here’s some of our eclipse chasing group enjoying a view of the southern hemisphere night sky, albeit though clouds. Jupiter is the bright object at left, Orion is rising on his side in the middle, Sirius is just above our stargazers, while Canopus is at far right. The Pleiades is at far left. We’re looking east, from a latitude of 16° south of the equator, where the sky takes on a completely new appearance that baffles and delights even seasoned northern stargazers.

– Alan, November 11, 2012 / © 2012 Alan Dyer