This image is stitched together from 16 frames, each a 60-second exposure taken with a 50mm lens. The sky frames are tracked, to follow the rotation of the sky and keep the stars sharp, and the tracker was turned off for the ground frames. This image spans 100 degrees, from west at left to north on the right, and about 70 degrees high.
Capturing all those frame takes about 20-30 minutes, and I started shooting about an hour before moonrise. This view is centered to the north-west, and the Milky Way is just off the image to the left, as it hadn’t rotated far enough west to be in position above the Bugaboos.
Reviewing the last captured frame, I notice a subtle glow on the spires, and visible shadows across the glaciers. This must be the moon starting to rise! And just like the sun paints the tops of the peaks with alpen glow just before sunrise, the moon is lighting up the tops of the spires just before it rises, behind me in the east. In a dozen years of night photography I have never seen, or captured, the lunar alpen glow; this is absolutely magical light!
During the two hours that we’ve been photographing the sky, we’ve been watching two climbers descend the Howswer Spires, their headlamps casting bright white pools of light on the glacier. After descending the Howsers, their route takes them around the north side of Pigeon, where they disappear from our view before re-appearing on the Bugaboo / Snowpatch col, and then work their way down the glacier to the Conrad Kain hut after what was likely a 20+ hour day for them. In this image, you can see their lights, on the slope just right of Snowpatch Spire.
The subtle green and red glow in the sky above the peaks is a faint aurora, which was only barely visible to our naked eyes.
On the left side of the image are the constellations Ophiuchus and Hercules, and within those constellations are several objects that at first appear to be large, fuzzy stars. A closer look with a much bigger optics reveals them to be immense clusters of 100,000s of stars, all orbiting each other in a dense ball; a globular cluster.
The brightest of these visible in northern skies is the M13 Hercules cluster, with 100s of thousands of stars packed into a region 150 light-years in diameter, visible in the above image on the right side of the torso of Hercules.
Where we live, in the suburbs of the galaxy, the nearest star to our Sun is just over 4 light-years away, but in a globular cluster the stars are packed in much closer together, and there would be 100-1000 stars in a volume of space 4 light years on a side. These globular clusters are truly ancient, between 11 and 13 billion years, making them almost as old as the Universe itself.
Galaxies also form groups, or clusters, held together by their mutual gravitational attraction. In the constellation of Ursa Major, on the right side of the above image, is the M81 group of 34 galaxies, lying about 12 million light-years away.
Galaxies M81 and M82 are interacting gravitationally, which is understood to have triggered a burst of star formation in M81, the larger, grand spiral galaxy. M82 is smaller than it’s neighbor and has also created millions of new stars recently. Additionally, M82 is spewing vast amounts of hot, ionized gas out of its central region, visible as bright red tendrils. This massive outflow of gas is thought to be driven by supernova explosions that are occurring every few years, making this active galaxy a very dangerous place! On top of all that action, M82 is thought to host intermediate-mass black holes that are consuming gas and emitting vast amounts of X-rays.
Also in Ursa Major is the beautiful M51 Whirlpool galaxy, another grand spiral galaxy that is also gravitationally interacting with its neighbor.
A 50mm lens is not the best tool to image things millions of light years away, so here are few photos of these galaxies taken with much bigger optics.
Also in this image is M97, the Owl Nebula, a planetary nebula in Ursa Major. Planetary nebulae have that name because they look rather like planets (small and round) through small telescopes, but in reality they have nothing at all to do with planets. They are actually clouds of gas, much larger than an entire solar system, explosively ejected by a dying star.
Arcturus, one of the brightest stars in the sky, is visible at the bottom of the constellation Bootes, just to the left of Snowpatch Spire. This aging star is only slightly more massive than our Sun, but has used up most of the hydrogen in its core and has expanded to about 25 times the Sun’s size. Arcturus emits about 170 times as much light as our Sun does today, and is a look at what our Sun will become in a few billion years.
The Messier catalog of deep sky objects was compiled by French astronomer Charles Messier in 1771, and was intended as a list of objects in the night sky that might be confused with comets. As telescopes and imaging technology improved, that catalog has become a list of some of the brightest and most awe-inspiring objects in the cosmos. In above image, of this relatively empty part of the sky, we managed to capture 14 of them, with three globular clusters: M12, M13, M92, ten galaxies: M51, M63, M81, M82, M94, M101, M102, M106, M108, M109 and one planetary nebula, M97.
Not too bad for a 50mm lens!
Researching this blog, I stumbled across another galaxy cluster, Abel 2151, which is just below Hercules. This cluster is far away – over 300 million light-years – and the galaxies are all 14th magnitude, so I can’t honestly say that the 50mm lens exposures actually captured any photons from these distant galaxies… but there are a bunch of fuzzy dots in the image at the exact location of this cluster.
Looking deeply at nothing
Everywhere you look, the night sky is filled with stars and galaxies beyond counting, but the key is putting the effort into looking hard enough. When the Hubble space telescope team wanted to farther into space than ever before, they needed to find the emptiest piece of sky they could, without any stars or interstellar gas clouds. In 1995 they chose a region of sky in the Ursa Major constellation, pointed the telescope at a completely empty patch of sky, and the most expensive telescope in history stared at nothing for over 100 hours, accumulating photons that had been traveling through space for billions of years.
The result of that deep stare was the astonishing Hubble Deep Field image that revealed about 3000 incredibly faint and distant galaxies. Because the speed of light is fixed, the farther away an object is, the longer light takes to get here. If a star in the sky is 100 light years away, the light we see today left the star 100 years ago. The nearest big galaxy, Andromeda, is 2.5 million light years away, more distant galaxies are 100s of millions of light years away; looking at those galaxies, we are looking 100s of millions of years in the past.
The galaxies in the Deep Field images have a wide range of ages, up to 12 billion of light years away. Perhaps more fundamentally, this image revealed just how incomprehensibly vast the Universe actually is; 3000 galaxies visible in a region of sky only 1/10 the width of the moon.
One arc-minute is 1/60th of one degree, or roughly the width of a standard soccer ball 756m away.
Side note: I was able to identify the location of the deep field image in the Bugaboos Moonrise image with the help of this 12-hour exposure image, taken with a amateur telescope, showing the deep field location and the sea of stars around it, in this “empty” part of the sky.
The original deep field was such a revolutionary image that since the 1995 experiment, the Hubble telescope acquired two more Deep Field images. The Ultra Deep field in 2004 was from a completely different part of the sky and totaled over 270 hours of exposure; that image was extended with infrared data captured in 2009 to produce the Extreme Deep Field (XDF). The XDF image is only 1/10 as wide as the full moon, the size of a soccer ball 300m away, and covers only 1/30 millionth of the full sky, yet contains over 5000 galaxies. A glimpse into infinity.
Feeling small yet?
The deeper you look, the more you discover… applies to many things in life.
– Darren Foltinek