May 2024 Solar Storm

The May 2024 solar storm produced northern lights aurora far to the south of normal locations. I got these photos in our back yard at around 2:30 AM on May 11.

The effect was very subtle. To the naked eye, it just appeared as very light cloud, no color. But the camera sensitivity picked up the faint purple and green hues. I did see it ripple across the sky a couple times as I was setting up the camera.

I created this crude timelapse video from the images. It jumps around as I move the camera around and play with different settings.

The storm is caused by sunspots. This post at the NOAA Space Weather Prediction Center and this article at CNN provide details. 

You can see how the sunspot pattern has changed recently by comparing photos of the sun on different dates. I took the images below with my cellphone held up to the eyepiece of the solar telescope I showed in TOTAL SOLAR ECLIPSE, APRIL 8, 2024. The first image is from that day. The second is from May 12; the sunspot cluster producing the storm is clearly visible.

Technical Details

I took the aurora photos with a Canon R100 camera, Canon RF-S18-45mm F4.5-6.3 IS STM lens at 18mm, f5.6. I was experimenting with different exposures, so the ISO was in the 1600-3200 range, and the exposure time was 4-6 seconds on the various frames. I had the camera on a tripod and used an external intervalometer to control the shutter in several bursts, 2 seconds between frames.

The timelapse video consists of all the resulting frames that were good enough, each duplicated 23 times to create groups of numbered copies. Then I used QuickTime Player: File > Open Image Sequence... to open the sequence and create a video at 24 fps. Each group of 24 total frames creates 1 second of video time. This is a crude but effective way to create a slow-motion timelapse; decrease or increase the number of frames per group to speed up or slow down the video.

I created this simple bash script dupframes.sh to duplicate the frames in a directory:

#!/bin/bash

if [[ -z "$2" ]]; then

echo "Usage: dupframes.sh <dir> <numframes>"

echo "Duplicate JPG frames in <dir> to <numframes> numbered copies."

else

ext="JPG"

source="$1/*.$ext"

numframes=$2

for f in $source; do

ls -l $f

for ((i = 0 ; i < $numframes ; i++)); do

framebase=$(echo $f | cut -f 1 -d .)

dest=$framebase-$i.$ext

cp $f $dest

done

done

fi