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
Oh, to be on the beach in the tropics now that winter’s here at home.
That’s where I was tonight, at the same beach on Magnetic Island, Queensland where I shot last night’s images of cloud shadows. You can see some of the same effect here, as the few darker clouds cast their dark shadows across the twilight. But in the clearer sky tonight, the classic colours of twilight are more pronounced than they were the previous night. The sunset sky goes from deep yellow near the horizon, through pinkish-purple and into deep blue high in the sky. The “twilight purple” is caused by red sunlight still illuminating the high atmosphere.
We see the same colour effects at temperate latitudes. It’s just a lot more pleasant enjoying a sunset on a warm beach in winter.
– Alan, November 22, 2012 / © 2012 Alan Dyer
I went to the beach to shoot the sunset and saw one of the best examples of cloud shadows I’d ever seen.
These are called “crepuscular rays,” and are shadows cast across the atmosphere by clouds, in this case in the west blocking the light of the setting Sun. However, here I’m shooting east in the direction opposite the sunset, to see the shadows converging on the anti-Sun point.
The effect is really stunning, yet I doubt anyone on the beach paid much attention to it. But then again, that’s the whole point of my AmazingSky blog — to call attention to neat stuff you can see in the sky if you only look up.
The site is Horseshoe Bay on the north end of Magnetic Island, off the coast of Queensland, near Townsville. I’m here for two days enjoying the island life. It has now been one week since the total eclipse of the Sun. Hard to imagine!
– Alan, November 22, 2012 / © 2012 Alan Dyer
This is the “director’s cut” movie of the November 14 total eclipse of the Sun in Australia, unabridged and unedited.
I shot this movie of the eclipse through a telescope to provide a frame-filling closeup view of totality. This is the entire eclipse, from just before totality until well after. So it includes both diamond rings: at the onset of totality and as totality ends.
A few seconds into the movie I remove the solar filter which produces a flash of light until the camera readjusts to the new exposure. Then you really see the eclipsed Sun!
We got 1m28s of totality from our viewing site near Lakeland Downs, Queensland. But the movie times out at slightly less, because at several points where you hear a shutter click, I took a still frame which interrupts the movie. You can see some of those still images in earlier blog posts.
My timing was a little off, as I opened up the exposure to reveal more of the outer corona only moments before the end of totality, so the first moment of the final diamond ring is a little overexposed. During totality I was looking with binoculars, and made the mistake of going over and checking on my other wide-angle time-lapse camera. That wasted time needlessly. I should have spent more time attending to the movie camera and taking more stills at various exposures. No eclipse every goes quite as planned. Losing 30 seconds of totality in order to seek out clearer skies did cost me some images and enjoyment time in the umbra. But our experience was far less stressful than those who dodged clouds (or failed to miss the clouds, in some cases) at sites closer to or at the coast.
The original of this movie is in full 1920 x 1080 HD, shot with the Canon 60Da through the 105mm f/5.8 Astro-Physics apo refractor, on an equatorial mount tracking the Sun. I rarely have the luxury of shooting an eclipse through such extravagant gear, as I would never haul that type of hefty gear now on an aircraft to remote sites. But this equipment emigrated to Australia in 2002 for the total eclipse in South Australia and has been here down under ever since. So this is its second Australian eclipse. Mine, too!
– Alan, November 21, 2012 / © 2012 Alan Dyer
On the eve of the November 14 total eclipse of the Sun, I was able to shoot the Milky Way setting amid the vertical glow of the evening Zodiacal Light.
This scene looks west toward the sunset point, but was taken well after sunset. The Milky Way and the area of Sagittarius where the centre of the Galaxy lies is just setting. The same area of sky contains a vertical pillar of light, very subtle, called the Zodiacal Light. This is sunlight reflected off dust particles orbiting the inner solar system and deposited by passing comets. The Zodiacal Light is best seen in the evening sky on dark moonless nights in spring, no matter what your hemisphere. But in this case it is November, spring in the southern hemisphere.
At left are the two Magellanic Clouds, satellite galaxies of the Milky Way, and visible at their best only from south of the equator. In this case we are at 16° South latitude.
The site is a lookout on the Mulligan Highway inland from Port Douglas where we made for the day before the eclipse and camped out overnight, along with a parking lot full of fellow eclipse chasers. But the morning still brought worrying clouds in the direction of the Sun, so we moved farther north to the site you see in my earlier Great Australian Eclipse blogs.
– Alan, November 20, 2012 / © 2012 Alan Dyer
During last week’s total eclipse, Venus was obvious above the Sun well before the shadow descended and the sky darkened. But during totality other stars and planets appeared.
But I suspect few noticed! During an eclipse your eyes are transfixed on the Sun and its corona. And on the other phenomena of light and shadow happening around you. However, I inspected my wide-angle frames and found faint images of Saturn and the stars Spica, Alpha and Beta Centauri, and three stars of the Southern Cross. I’ve labeled them here but you might not be able to pick them out on screen in the reduced resolution that appears in the blog. Similarly, I doubt anyone saw them visually. If you did you were wasting your time looking at the wrong stuff!
– Alan, November 18, 2012 / © 2012 Alan Dyer
I began my journey to Australia with a visit to the replica of James Cook’s ship Endeavour in Sydney. I’m ending this part of my trip with a visit to where Cook beached the HMB Endeavour for repairs at what is now Cooktown in far north Queensland. This is where Cook spent the most time in Australia, though not by intention.
In 1770 Cook was sailing north along the Queensland coast, after visiting Tahiti the year before to see the transit of Venus. He inadvertently discovered the Great Barrier Reef. Endeavour ran aground on what is now called Endeavour Reef. The crew was able to repair the ship well enough and save themselves by getting Endeavour to this harbour at what is now Cooktown where the Cook River meets the Coral Sea. There, with the ship beached, they were able to effect more permanent repairs to its damaged hull.
The site is just below this viewpoint at an idyllic harbour. They stayed there for two months in July and August 1770, effecting repairs and sighting, among other curiosities, kangaroos for the first time.
I visited Cooktown yesterday as part of a 4WD trek up the Bloomfield Track north of Cape Tribulation and through the Daintree Rain Forest. At Cooktown its museum, converted from an old convent, contains the original main anchor and one of the large canons from Endeavour, recovered from where the crew tossed them overboard to lighten the ship’s load and gain draft to sail off the reef. They are some of the few pieces of Endeavour that still remain.
– Alan, November 17, 2012 / © 2012 Alan Dyer