Friday, May 21, 2010

Seasonal Signs

Thursday, May 20, up at the college library, where the windows are tall and wide and look across the harbor and the Strait, all the way to Canada. "You just missed a submarine," said J. when I arrived. "I looked on and it wasn't listed." "Nah, the coast guard cutters and the escort vessels and the subs are never listed. Obviously they transmit, but on other frequencies and other people watch them." Later there was a container freighter passing the end of the Hook. With binoculars you could read the big "Hapag-Lloyd" on the side, but not the little letters on the bow. said she was Bremen Express, en route to Tokyo.

Later still the ferry caught my eye. There it goes. I waved at it, then looked wildly at the clock. Why is it on the move at 1PM? Ah. Early summer schedule: three runs a day, beginning today. 8:20 12:45 5:15. Last return from Victoria docks at 9PM. Sure enough at 9 I heard its horn in the darkening evening, 'hoooooome-home-home'.

Darkening evening, 9 PM. The days already nearing as-long-as-they-get. Right now:
   Thursday 20 May 2010 Pacific Daylight Time
    Sunrise 5:29 a.m.
    Sunset 8:53 p.m.
    End civil twilight 9:31 p.m.

Earliest sunrise seems to arrive on (and stay the same for a few days after)
   Saturday 12 June 2010 Pacific Daylight Time
    Sunrise 5:13 a.m.
    Sunset 9:14 p.m.
    End civil twilight 9:55 p.m.

Latest sunset seems to arrive on (and stay the same for a few days after)
   Saturday 19 June 2010 Pacific Daylight
    Sunrise 5:13 a.m.
    Sunset 9:17 p.m.
    End civil twilight 9:59 p.m.

This post serves as your annual reminder that the earth is tilted, and this daylight thing—the earlying of sunrise and the latening of sunset, and back again—is not symmetrical. I've never succeed in explaining it, barely can grok it myself. 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.


robin andrea said...

I hadn't ever seen that photo before, so I'm really glad you posted it. I spend a lot of time trying to figure out where the sun is going to be at certain times of the day. It's especially important when planning a garden. I found this website that helped me get an idea of where the sun will be at its highest angle, on any day of the year.

mb said...

There's a wonderful story about the photo. It took two years to get the image, because the first year the camera was mis-aimed and part of the figure was off the film. I can't find the original article, but I know it was done about the latitude of Boston, once a week at about 8 AM, with the shutter left open to get the streak on the solstices and one equinox... :-)