This Light

"What do you know about trigonometry?"

This blog will strive to post on the solstices and equinoxes. I've already missed the vernal equinox by a day. Or two, depending on who's equinox you follow - that of the church, or that of astronomy.

"I could care less about trigonometry."

Yesterday, the ecclesiastical vernal equinox, I raised a 12.5 inch stick, and at local noon, it cast a 9.5 inch shadow. The arc tangent of the ratio of stick to shadow length declared the sun to be 52 degrees off the horizon. I don't know much, but I do know my latitude is 38 degrees. And I know that yesterday the sun was directly over 0 degrees latitude, a spot on the earth 90 degrees between me and the sun. Is it coincidental that 90 - 52 = 38?

"Without trigonometry, there'd be no engineering."

I'm trying to determine the best date for maximum solar gain on the PV panels, which are oriented south at 19 degrees off the horizon. Supposedly, 90 - 19 = 71, a 71 degree sun angle would be perpendicular to the array. Going forward a few weeks or months, it seems that I should receive more energy as the sun rises in the sky. But...the temperature of the array will change, likely offsetting these gains.

"Without lamps, there'd be no light."

I will have to do this experiment again on the solstice. More trig will be needed, as then the sun will be 23.5 degrees in latitude.