Antarctic Sundial

TFE Experiment #14 “Shadow length and direction”

The geometry of the globe predicts the azimuth and zenith angles of the sun for any location on any day. Within the Antarctica Circle near the December solstice the globe predicts that the sun will not set. The proximity to the South Geometric Pole determines how many days the sun will remain above the horizon. On the Antarctic Circle there is 1 day, at the pole 6 months.

I was at Union Glacier at 79°44’24″S, 82°48’21″W on December 14-17, 2024. We made predictions based on the location and the geometry of the globe for the sun’s angular elevation and horizontal angle.

Based on the geometry of the globe the sun must be at 13° angular elevation at local solar midnight and 34° at local solar noon for December 14-17, 2025. Here is a detailed diagram based on the location and time: Sundial

I set up a sundial using chunks or “boulders” of snow in a somewhat elliptical patter around a 165cm tall gnomon, then used an Insta360 camera on the gnomon to record over 24 hours of the area. This included the angle and length of the shadow and the presence or the 24 hour circling sun.

Here is the timelapse of the shadow on the snow boulders: https://youtu.be/n9_cU3EDWG4

Here is a timelapse of the sun for 24+ hours: https://youtu.be/xR3wPw2MoG0

Here is the real time interactive 360° video:

The videos are split up because YouTube only allows 12 hours per video and the full video is over 24 hours.

You can download and analyze the full, unmodified files copied directly from the MicroSD card that was in the Insta360 x4: https://www.dropbox.com/scl/fo/sdf4vlxjj7lw1maeg4onb/ABVPmhLDugQl4shmRdcEKT8?rlkey=b1ads17e466fjefm3xo1h2yzr&dl=0

This folder is just under 1TB. You will find “.insv” files which are the high res dual MPEG stream videos, and “.lrv” files which are single MPEG stream low res videos. You can import all or some of these into Insta360 Studio to create your own videos. When publishing link to this page.

The content is shared under the Attribution-ShareAlike 4.0 International license: https://creativecommons.org/licenses/by-sa/4.0/