Milky Way Panorama over Turret Arch

About 10 years ago, as I was scouting Utah’s Arches National Park looking for fresh vantage points, I discovered that I could see South Window through Turret Arch if I scrambled up onto a two-foot-wide ledge above a 20-foot vertical drop. I made careful measurements of the opening in South Window with a pocket transit (a highly accurate compass and inclinometer) and learned after some research that the sun would rise through both arches simultaneously on just eight days per year, four in April and four in August. After failing in April due to persistent clouds, I returned in August and shot Turret Arch through South Window on 4x5 film.

I never forgot that unique vantage point. In the spring of 2016, when I was searching for good places to shoot the Milky Way, I suddenly realized that I might be able to create a completely different kind of image from the same precarious point of view. I was now equipped with a Canon 5D Mark III, which has the stellar high-ISO performance required to shoot the Milky Way. Even with my Canon 16-35mm f/2.8L II set to 16mm, however, I knew I’d need to shoot a panorama to capture the full width and height of the Milky Way as it arced from horizon to horizon. 

To determine if my idea would work, I needed to know the altitude (angular elevation) of the top of Turret arch, as well as the azimuth (compass bearing) of the right and left sides of the arch. I dug back through my files and located a photo I’d made of the moon rising over Turret Arch at sunset. By checking the metadata, I learned the exact date and time I made the photo. When I set that date and time in Photo Ephemeris Web, I learned the precise azimuth and altitude of the moon. Combining that information with the angle of view of the lens I used, I could estimate both the altitude of the top of the arch and the azimuths of the left and right side. I took that information to an astronomy app called SkyGazer to see if the Milky Way would ever be in the right position, soaring above the arch but not straight overhead, which would make the shot unworkable. (Today I would either use Photo Ephemeris Web again or use an app called Sun Surveyor.) I also wanted the galactic center, the brightest part of the Milky Way, to be far enough above the horizon to be photogenic.

To my delight, my research showed my plan was feasible. I made plans to visit Arches that April during new moon. This time, older and wiser, I brought a rock-climbing harness and hardware so I could anchor myself and my tripod to the cliff. Thus secured, I was able to shoot several panoramas with Really Right Stuff multi-row panorama hardware. I shot two frames at each camera position, exposing one for land and one for sky, then blended the two sequences in Photoshop and finally produced the image you see here.