Star-Stabilizing the Entire Sky (spherical distortion)

2018-12-02

[public] 65.8K views, 3.22K likes, dislikes audio only

I like to think of this as the whole sky always being "there", but the Earth blocks about half of it ALL THE TIME! Alternately, if we look straight "up", we're always pointed towards a different part of same sky. I made these reprocessed spherical timelapses to hopefully communicate these perspectives. I think it's pretty incredible how the sky acts like an ever-changing window on our universe.

I shot this timelapse over the course of about a week. (the camera was pretty tired and I went through a bunch of 64BG SD cards...) I ended up finally capturing one good 24-hour span with the camera pointed up, and one good 24-hour span with the camera pointed down.

I was using a circular fisheye lens with a 185 degree field of view to capture the entire sky in a single photograph. I also flipped the camera over to take a picture of the ground and capture a full spherical image (albeit separated by a day). I did a whole lot of math and editing in Lightroom (twice for each of the "up" images), Matlab for color temporal smoothing, Davinci Resolve for stabilization and looping, back to Matlab for spherical "unfolding", back to Resolve for compositing the top and bottom images, back to Matlab again for redistorting into the "tiny planet", and finally back into resolve again for a final render. I also passed a few frames through Imagej in order to measure some angles I needed for the polar alignment and "star stabilization". After all that I think it turned out pretty cool!

Camera:

Sony A6000 - Aperture priority, auto-ISO, AWB

Lensbaby circular fisheye (E-mount) - adjusted aperture at sunrise and sunset to control light)

External intervalometer set to 1:20/frame (enough time to process a max 30 second exposure and associated dark frame)

Case-relay power system (plugged into the wall, you can see the orange cable on the ground...)