Curved Milky Way

I’ve often admired those pretty pictures of the Milky Way arcing across a beautiful landscape–for instance, this NASA APOD.

We went to the beautiful Muir Trail Ranch a couple weeks ago and were fortunate to be at the ranch (which has a beautiful very dark sky) on nights when the moon didn’t rise until after 1am. I had my camera and tripod with me, so I thought I’d try capturing one of those curved Milky Way images.

Here’s a picture I like from that trip:

You can see my full album here.

Although the Milky Way really is in a pretty straight line, it’s a straight line on the apparent sphere that is our sky. Projecting enough of that sphere onto a flat image causes the straight-line Milky Way to appear curved.

I thought I’d share my workflow for these shots.

1. Most important: Location. Location. Location. Go to a location with a very nice sky and nice foreground. I was at a great one.
2. Composition: Find a spot where the composition is good and any annoying foreground lights are blocked as much as possible. I had a nice sky and beautiful ranch buildings as foreground, but I was fighting some difficult floodlights left on all night. I didn’t consider asking for them to be turned off, but if that’s a possibility for you, it makes processing and shooting a lot easier.
3. Equipment: I use a (mirrorless) DSLR with a wide-angle lens attached, mounted on a nice tripod. If you are a serious photographer, you likely already have these. I’ll bet one could take decent Milky Way pictures with a smart phone (with an app that allows manual exposure controls), and some sort of make-shift tripod that allows swiveling, but a DSLR makes things a lot easier. If you don’t want the curve in the Milky Way, a tripod is not necessary (but don’t hand-hold your camera, place it on something solid and use a timer).
4. Level the tripod: I’m taking a panorama, swiveling the camera across up to 180 degrees. I want the ground to be in a pretty similar spot across the picture, so I need a level tripod.
5. Focus the Camera. I auto focus on a bright star (actually I used Jupiter, the brightest thing in the sky, those evenings). Then, I switched the camera to Manual Focus mode, so it kept that focus. You want to repeat this periodically to make sure you haven’t lost focus. Some of you might do the manual focus directly, but I don’t trust my ability to do that.
6. Set the Exposure: I use a pretty wide lens wide open, a Fuji 14mm f/2.8, with a Fuji X-T2 (1.5x crop sensor) camera, and I manually exposed at 10s, ISO 3200, f/2.8, RAW.
7. Frame the Panorama. I attached my camera to my tripod head vertically and level, with the bottom of the frame a bit below the buildings in my composition. Depending on the time and season, the top of the frame may not be above the top of the Milky Way. Bummer if that’s so 😦 The Milky Way, like all objects in the sky, will rise in the east and set in the West. It’s best shot in the summer months where I live. By midnight in July at the Ranch it was too high in the sky for my 14mm, and I would have needed a wider lens. I suppose one could try a 2-D panorama in that situation, but stitching that panorama is tricky.
8. Inspect. I panned left and right across my compositions and made sure things looked good. I used a “viewfinder level” to show me that the image is still near level across my composition. If the tripod is level, and the camera is mounted level on the tripod, the image should stay level.
9. Setup the timer. Since I’m using long exposures, any shake on the camera (including that from pressing the shutter) will cause blur on the image. I used a 2-second timer, so that I could press the shutter, wait 2s, and get a clearer image.
10. Finally take the images. I started from the right, e.g. getting Jupiter on the left side of the first frame, to give me some margin, and then rotated left, about 2/3 of a frame for each image, going a frame past where I was interested. This doesn’t need to be exact. I often guessed, but I error on the side of more overlap rather than less. I typically wound up with 8-10 exposures per panorama.
11. Experiment with different exposures. I also tried 20s at ISO 3200, and 10s at ISO 6400, and probably some other variations. I made sure my star trails weren’t too pronounced. I was a little worried about the 20s shots. On the other hand, I made sure I had enough exposure to see the Milky Way.
12. Iterate. Iterate. Iterate. It’s key to repeat the whole process for several different compositions (and maybe even several different nights). I move around. I try different foregrounds. If possibly, I note where the tripod was set up for my different variations that I may come back to. I try different strategies for avoiding any nasty lights that might be affecting my shots. I process my shots the next day, and plan what I want to try differently the next evening.

I probably shot about 20 panoramas during the three nights I attempted this. I was in a meadow for 1-2 hours each night, between 10pm and midnight.

Processing. I processed my panoramas with Adobe Lightroom, selecting the pictures in one panorama, and using Photo –> PhotoMerge –> Panorama, and selecting the Spherical Projection. That seemed to work well. After that, I used standard cropping, and exposure controls. The main processing difference to most of my other photography is probably that I sometimes pushed the Lightroom exposure for these more than I usually do, or used more extreme Highlights, Whites, Shadows or Blacks settings. Also, I sometimes had to use heavy local adjustments to tone down those lights on buildings that were too bright.