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

 

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