Friday, November 19, 2010

Duration of Daylight/Darkness

New toy. Duration of Daylight/Darkness Table for One Year. Thank you, US Naval Observatory. From their Sun or Moon Rise/Set Table for One Year we get the annual happynews that earliest-sunset will arrive on December 7, so it's already darn near as bad as it gets. Sunset today, 4:31. In a couple of weeks, 4:20. Then it turns around.

Reader, it's different where you are. Use the tables.

A couple of times a year I fret about the assymetry... Quoting myself in May: Whenever the topic arises I look at the first analemma photo (a one year multiexposure photo of the sun at the same time of day), the one taken by Dennis Diciccio in 1978. I see the tilt. I sigh and say, ok, I get it, just for a thought-moment.

1 comment:

robin andrea said...

Great new toy. I love looking at charts like this. My obsession with sunlight has to do with how much light will be available in the winter, and at what angle, for me to get some Vitamin D from it. It's much harder to derive "D" from the winter sun, but I still try. I also dry our laundry outside as often as possible. So, I've been watching how low the sun sinks behind the pines on our southern border. So far, we still have pretty direct sunlight until about 1:00 pm. It's not going to change too much between now and the darkest days. I breathe a sigh of relief.