Happy first day of spring! Although here in Seattle, it starts out stormy with 40+ kt gust winds, lowered freezing level, heavy rain, and no view of Comet PanSTARRS. Typical spring for the last 4 years now. Global warming? Nah...I call it more like "global climate shift".
How many times have I had the Astro-Shack dome open since I built it last summer? Uh....3 times maybe?
Anyway, here is a nifty video showing the seasons of Earth from above. Spring/fall is when the terminator is straight up and down.