2024-10-11 | [misc]
I happened to see the notice for a G4 level event on the NOAA space weather page.
I live between the solid red area and the View Line limit, so there was a chance. All I had to do was get my camera, wait for it to get dark, and go outside.
These were all taken at a high-ish ISO (3200-6400) and 1-4 seconds of shutter open time. The lights weren't all that visible to the naked eye, unless you are pretty well adjusted to the dark. Mostly, you might be able to tell that a part of the sky was unusually red or green colored. If you look really carefully, you can make out a vertical streak or two, but in person it mostly looks a bit like weird clouds. The lights change on the order of minutes - faster than a rain storm moves, but too slow to be notice by eye. For about 10 minutes, the patterns became bright enough to appreciate the full spectacle without the camera's long exposure.
I also tried holding the camera button down, which makes my camera do a rapid fire mode. At a shutter speed of a few seconds + processing time, this comes in at a capture speed of about 1 images/10 seconds. Ok for an impromptu timelapse over a few minutes (I did not make an intervalometer).
To make a timelapse video of a bunch of JPGs in a directory, I do this:
ffmpeg -framerate 5 -pattern_type glob -i '*.jpg' -c:v libx264 -pix_fmt yuv420p output.mp4
and then to make that video into a gif (and downscale it so the width is 1000 pixels)
ffmpeg -i output.mp4 -vf "fps=5,scale=1000:-1:flags=lanczos" -c:v gif output.gif
Note that if you lower the fps in the second part, it will limit the fps but leave the duration unchanged (it doesn't slow down or speed it up).