The Glowing Clouds of Solstice Appear


The glowing clouds of solstice have appeared. This was my first sighting of “noctilucent clouds” for the season.

Every northern summer in late June and early July we are often treated to bright pearly clouds glowing along the northern horizon long after sunset. Their origin remains somewhat of a mystery. These clouds form almost at the edge of space, so high there shouldn’t be much for clouds to form around. But their height is what makes them visible, as they catch sunlight streaming over the pole even in the middle of the night.

I took this shot Tuesday, June 28 just before midnight. The noctilucent clouds are the blue-white wavy bands just above the orange twilight. In front of them lie dark normal clouds low in our troposphere. But the NLCs shine from an altitude of some 80 km, well into the mesosphere. They are located over the Northwest Territories but, like aurora, their height allows us to see them even from more southerly latitudes.

The bright star Capella, circumpolar from my latitude of 51° North, shines through the clouds at right.

— Alan, June 28, 2011 / Image © 2011 Alan Dyer

Centaurus, Creator of Constellations


In George Lucas mythology, Luke Skywalker went to Yoda to learn the wisdom and ways of heroes. In Greek mythology, heroes the likes of  Achilles, Jason and Hercules sought out Chiron, the wise and kindly Centaur, who taught them science, astronomy, medicine, music, arts, hunting and archery.

Centaurs, the romping half man/half horse creatures, were a riotous and drunken lot, but not immortal Chiron. He was the offspring of Kronos and the ocean nymph Philyra and served as tutors to many legendary heroes. One reference in my library suggests Chiron actually invented the constellations, to make it easier for mankind to keep track of the stars and the season. To reward his work, Zeus placed Chiron in the stars, becoming by some accounts, this southern sky constellation, Centaurus.

However, most writings suggest Chiron is actually the Zodiac constellation of Sagittarius, while the constellation we call Centaurus is one of the wilder bunch, depicted in the sky as carrying the slain Lupus the wolf, drawn here in the fainter blue stars at top centre.

The bright stars at right are the main stars of Centaurus, including Alpha and Beta Centauri at lower right. Beta Centauri is the blue star, a giant some 390 light years away. But just to the left of Beta is yellow-white Alpha Centauri, a Sun-like star (or actually a pair of them orbiting each other) just 4.3 light years away.

Alpha and Beta Centauri sit at the start of a long dark rift in the Milky Way that splits into fingers of nebulosity reaching into Norma, Ara and Scorpius, here at the left edge of the frame.

I took this shot of Centaurus and Lupus in Chile last month, using a 50mm lens and a Canon 5D MkII. It’s a stack of four 6-minute exposures at f/4 and ISO 800, layered in with two exposures shot through a Kenko Softon-A filter to produce the photogenic star glows.

— Alan, June 26, 2011 / Image © 2011 Alan Dyer

 

 

 

 

 

Summer Solstice Space Station, Part 2


Here’s a capture of the Space Station, coming over in a darker, clearer sky than last night’s shot (in the previous blog). This was June 22, 2011, a fine solstice night on the Canadian Prairies.

The time was just before midnight, with no Moon. Yet the sky is blue and the northern horizon tinged with the orange glow of twilight. It never gets truly dark now, as summer begins. To the right, on the northeast horizon, a low green aurora kicks up.

The Space Station, the dashed arc at top, tonight passed from west to southeast, across the southern sky at the top of this fisheye 360° frame.

This is a stack of 28 18-second exposures at f/4 and ISO 1600 with the Canon 5D MkII and Sigma 8mm lens.

— Alan, June 22, 2011 / Image © 2011 Alan Dyer

 

 

Summer Solstice Space Station


We’re currently enjoying a series of nightly (and often twice or thrice nightly) passes of the International Space Station, coinciding with the bright nights of summer solstice.
I took this shot on the night of solstice, June 21, 2011, as the Space Station came directly overhead, flying out of the west then heading off into the east. So we’re looking a little west of north here, toward the bright northern horizon. Pity some light cloud hazed up the sky. The pass began at 11:12 pm so the sky was still quite bright, though even an hour or two later at this time of year the northern horizon is tinged with perpetual twilight glow, at least at my latitude of 51° N.
To create the image I took a series of 100 3-second exposures (as long as the bright sky would allow) taken 1 second apart in rapid-fire fashion with the camera firing automatically with a remote timer. The 1 second gap between exposures creates the gaps in the Space Station trail.
I processed the images in Adobe Camera Raw, and exported them all as TIFFs to their own folder. I then used Chris Schur’s excellent “Star Trails” Photoshop Action to stack all those images into one composite image showing the complete flight of the Space Station across the sky. A little application of Shadows and Highlights helped bring out the foreground and bright sky detail.
I used the Sigma 8mm fisheye lens and Canon 5D Mk II to capture the whole sky, for a still and time-lapse sequence suitable for projection in a full-dome video planetarium … because the neat thing about this method is that the same set of images can be strung together sequentially (using Photoshop Extended’s Movie function) into a time-lapse movie of the pass, showing cloud and star motion as well as the ISS passage. The same techniques work for star trails, as indeed you can see here with the stars of the northern sky (Big Dipper at left and Cassiopeia at right) trailing around the North Star.
— Alan, June 22, 2011 / Image © 2011 Alan Dyer

The Moon in June


On one of the few clear nights of late I took the opportunity to shoot the Moon. It’s a familiar subject to be sure, but one I don’t shoot very often. Pity really, as it is rich in detail and makes for dramatic photos.

I took this shot June 12, about 4 days before the Full Moon of June, so this is a waxing gibbous Moon. Lots of terrain (lunain?) shows up at left along the terminator, including the wonderful semi-circular bay at about 10 o’clock called Sinus Iridum. At the bottom is the bright Tycho crater, with its distinctive splash of rays spreading out across most of globe. Imagine the devastating impact that caused that feature! It isn’t that old either — estimates suggest Tycho is just 100 million years old, putting its formation smack dab in the middle of the Cretaceous Period when dinosaurs ruled the Earth. They would have seen that impact, little knowing another similar-sized impact 35 million years hence, but aimed at Earth, would do them in.

For this shot I used the Astro-Physics 130mm apo refractor with a 2x Barlow lens to increase the effective focal length to 1600mm, a combo that exactly fills the frame of the Canon 7D with no room to spare. I processed this image for high contrast, to bring out the subtle tonal and colour variations in the dark lunar seas, an effect due to different mineral content of the lava that oozed out forming the lunar plains. Judicious use of Highlight Recovery (in Camera Raw) and Shadows and Highlights (in Photoshop) brings out the detail across a subject with a huge dynamic range in brightness. A liberal application of Smart Sharpening also helps snap up detail.

— Alan, June 18, 2011 / Image © Alan Dyer 2011

 

 

Into the Heart of the Scorpion


Here we peer into the heart of Scorpius, to a place where the sky is painted with pastel hues unlike anywhere else in the heavens.

The yellow star at bottom is Antares, the cool supergiant star that marks the heart of the Scorpion. To the right is Messier 4, a globular cluster of thousands of stars. Wrapping the entire field are shrouds of dust, reflecting the yellow light of Antares and the blue light of hotter stars above, such as Rho Ophiuchi at top right. Glowing hydrogen gas clouds add the magenta hues.

The remarkable feature of this field are the dark fingers, clouds of dark interstellar stardust glowing with a dim yellowy-brown hue. In places the clouds become more opaque and intense, blocking any light from background stars. Those clouds must be close by in our galactic spiral arm because few stars lie between us and their dark masses. Estimates put them about 400 light years away.

The entire region is a busy factory of star making, one of the closest to our Sun. Chances are our solar system formed in a similar star factory 5 billion years ago, one that has long since dissolved away and dispersed around the Galaxy.

Like the previous shot, this is a Canon 7D/135mm telephoto image in a stack of six 2-minute exposures, taken from Chile in early May. I find it remarkable that with digital cameras just 2-minute exposures not only bring out the dark nebulas, but actually show them with colour and tonality. In the old days, film shots 20 minutes long only ever showed them as a mass of underexposed and featureless black.

— Alan, June 16, 2011 / Image © 2011 Alan Dyer

Off the Stinger Stars of Scorpius


Off the tail of Scorpius lies one of the great starry regions of the Milky Way. From southern Canada the Scorpion’s Tail barely clears our horizon at this time of year, on June nights. But from farther south, Scorpius crawls high into the sky — and the sky actually gets dark at solstice, so stargazers can see the starclouds of Scorpius in all their glory.

At right, the blue stars mark the “stinger” at the end of the Scorpion’s tail. The brightest one, called Shaula, or Lambda Scorpii, is a hot blue giant star some 10,000 times more luminous than our own modest Sun. It is also a triple star, with another luminous blue star orbiting it, plus a third odd mystery star thought to be either a neutron star or perhaps a young proto-object still in the process of forming a proper “main-sequence” normal star.

To the left lie two prominent clusters of stars: at top the Butterfly Cluster (a.k.a. Messier 6), a bright group of stars sitting amid a dark bay of dust. Below it, almost lost in the stars, is Ptolemy’s Cluster (a.k.a. Messier 7), that is an obvious sight to the unaided eye – so obvious the Greek astronomer Ptolemy catalogued it in 130 AD. Several other star clusters pepper the field.

This telephoto lens shot frames the field as binoculars would show it. I took this from Chile in early May, using the Canon 7D and 135mm lens, for a stack of six 2-minute exposures at f/2.8 and ISO 1250.

— Alan, June 16, 2011 / Image © 2011 Alan Dyer