Milky Way over Mt. Sneffels
Milky Way over Mt. Sneffels, Mount Sneffels Wilderness, Colorado
Just try to wrap your head around these facts: there are between 100 and 400 billion stars in our Milky Way galaxy, and between 100 and 200 billion galaxies in the universe. Loosely speaking, our galaxy is shaped like a plate, not a sphere. The Milky Way is the bright band that we see as we look along the galactic plane. It’s made up of billions of stars that are so distant our eyes cannot resolve them into points. Our solar system is not in the middle of the galactic plate, but rather part way out toward the plate’s edge. If we look away from the center of the galaxy toward the outer edge of the plate, our line of sight leads through relatively few stars, and the Milky Way is faint. If we look toward the center of our galaxy, on the other hand, there are many more stars between the Earth and the outer edge of the galaxy, which means the Milky Way is much brighter. In addition, there are vast clouds of gas and dust in the galaxy’s center.
The galactic center is the brightest and most photogenic part of the Milky Way. Like any astronomical object, it appears to rise and set as the Earth rotates. For any particular latitude, the direction to the galactic center when it rises and sets remains the same, but the time of rising and setting varies with the season. By choosing the right location for my camera, the right time of night, and the right time of year, I was able to position the galactic center so it arced up and over 14,150-foot Mt. Sneffels, one of Colorado’s famed Fourteeners, in the Mount Sneffels Wilderness near Ridgway.
Even the brightest part of the Milky Way is inherently dim. To capture the best possible detail, I used a Sony a7R IV camera and Sony 35mm f/1.4 lens mounted on an iOptron star-tracker. After aligning the tracker to point toward Polaris, the North Star, the tracker moved the camera in the right direction and at the right speed to counteract the apparent motion of the stars, enabling me to make long exposures at low ISOs without the stars turning into streaks. The result was sharp stars, reduced noise, and enhanced detail in the final image. To further reduce noise, I made multiple exposures for the sky using the tracker, then turned off the tracker and made multiple exposures for the land. I stacked the sky frames in specialized astronomical software which realigned the stars and reduced noise, then stacked the land frames in Photoshop and used Photoshop’s Stack Mode>Median utility to reduce noise. Finally, I combined the good-sky frame with the good-land frame in Photoshop.
The technical details of making this image were complex, but the goal was simple: to make an image that captured the wonder and awe of standing under a starry sky, marveling at the immensity of the universe, as the Milky Way shone brightly over one of Colorado’s most dramatic peaks.