Gauge for Length of Day (showing Solstices & Equinoxes)


Happy Winter Solstice everyone!

Thanks to TWC’s seconds, my dials were more accurate this year than ever before…


When I examine the code, today’s day length was actually 6 seconds off from my actual location. I cannot blame my math… I cannot blame webCoRE… It is simply TWC reports the sunrise and sunset for a station a few miles away.

If anyone else wants to calibrate THEIR piston, I recommend running these two expressions today… right now… before midnight hits


Save the results to a text file, then later on, when you are bored, you can do the math to find the shortest day that TWC sees for your location.


Wow… Sometimes I am really impressed with my math…

Earlier this year, I estimated that using TWC for sunrise & sunset times will bring the results within 0.007% of accuracy…

The results for this year are in…

This Winter Solstice returned 0.042%… (instead of 0%)
(Which is exactly 6 seconds off, due to my location)
and of course…
0.007 x 6 = 0.042

The math could not be any more perfect!!
(not that anyone else cares, LOL)


First full day of Winter, and the new colors switched over on schedule…


The next six months, the dial will be moving towards the right…