A trip to Yellowstone National Park isn’t complete without seeing Midway Geyser Basin. A boardwalk leads you to the colorful Grand Prismatic Spring. At 370 feet in diameter and over 121 feet deep, Grand Prismatic is the park’s largest hot spring. This jaw-dropping multi-image panorama shows Grand Prismatic Spring at night with the Milky Way sparkling above it and the stars reflected in the water below. Image courtesy of David Lane.
Otherworldly, surreal and unreal are all words that have been used to describe this image, but people also want to know if it’s real. The answer: Yes, but you have to know a little about astrophotography to understand the image. First, the image is 16 individual images stitched together (not stacked like HDR) to create a large panorama of the night sky. The stitching creates the curve in the Milky Way in order to keep the ground straight (think of it like taking an orange peel and laying it out flat, the sphere gets distorted). The Milky Way is colorful because camera light sensors can pick up more light than the human eye (most people just see the stars in black and white) and using an exposure of 15 seconds for each image helps illuminate the sky and foreground more. This photo also shows air glow radiating out of the horizon and the aurora in the left corner.
If you were to visit Midway Geyser Basin on a clear night, you would see the stars in the sky in black and white, plus the airglow and aurora, and the foreground would be dark.