Friday, August 1, 2008

Missed it by that much ...

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No this is not a review of the "Get Smart" movie. Nor is it a discussion of another asteroid near miss.

Rather, it's an eclipse near miss. Now I'm sure some of you are thinking, a what near miss? Let me explain.

Earlier this week, I was up early and noticed a post about the August 1st Total Eclipse at Visual Astronomy, here. Now I'd completely forgot about the eclipse because I knew about it and dismissed it months ago (because I would be in the wrong place). But when I read the times on Sean's site, I briefly thought there might be a chance to see one of these rare events. A quick check (see below) dashed that small hope.
  • NASA maintains eclipse web pages, here. A map projection of today's eclipse is here.
  • And there is a wonderful eclipse calculator that will tell you if you can see an eclipse, here.
Right now, I'm on vacation in Maine about a 2 hour drive south of Waterville which will see a partial eclipse (about 25%) at sunrise for 59 seconds! Such a brief glimpse and the weather forecast don't justify a 4 hour return commute. Pity.

I should say a word about why solar eclipses are rare. In one sense they are not. They tend to group with lunar eclipses like the one last February, see Snow Moon Eclipse - simple astrophotography about every 5-6 months. The reason we don't get eclipses every month is that the orbit of the moon is slightly inclined to Earth's orbit around the Sun. Consequently, during most months the Moon is off center and the shadows fall in the wrong places to be seen.
  • Lunar eclipses, where the shadow of the Earth falls on the moon, are visible from anywhere on the night side of the Earth. They also last several hours.
  • Solar eclipses, where the Moon's shadow falls on the Earth, last only a few minutes and are only visible across a limited geography (as can be seen in the eclipse map above). The shadow of the total eclipse is visible across an extremely narrow track across the daylight side of the Earth. Solar eclipses are also dangerous to view unless you have proper equipment.
This article was post dated. Right now, I'm asleep dreaming of a day at the beach and seeing a Portland Seadogs game tonight. Sadly, I missed David Ortiz's sell-out appearance last week.

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