[X] My Assistant

[Stu]

People in China will be able to see a total solar eclipse on Friday. Here in the UK we'll see a partial solar eclipse - not a very dramatic one, but still worth watching. Full details here...

Note: these times are for my home in Kendal, Cumbria, but wherever you live in the UK your times won't be drastically different, and a quick Googlehunt will help you track down accurate times... board members in certain other countries will be able to see the eclipse too, but I don't have specific visibility details. Again, just Google it.

This is just a "heads up" to make sure you all put it in your diaries...

[scalbers]

As kind of a second order consideration, it's interesting about the factors increasing the duration at the noon portion of the track vs at the sunrise/sunset. It's true that at the noon portion, one is closer to the moon and this makes the shadow bigger and the eclipse longer. However, the earth's rotation also slows the relative velocity of the shadow mostly near the noon point. For short eclipses, the distance effect would be more important, while for long eclipses I think the rotational velocity effect becomes more dominant.

The 2009 eclipse is one saros cycle later than the similar 1991 eclipse in Hawaii and Baja California. My processed image of that eclipse is on my home page:

http://laps.noaa.gov/cgi/albers.homepage.cgi

[BPCooper]

It's true that at the noon portion, one is closer to the moon and this makes the shadow bigger and the eclipse longer. However, the earth's rotation also slows the relative velocity of the shadow mostly near the noon point.

Being at the noon portion of the track comes into play in hybrid eclipses (2005 was the last one). In those cases the moon and sun are right on the border of being the same size in appearance, such that the eclipse can be total along the middle part of the track, but the Earth's curvature on the ends is enough to be farther away and it becomes an annular eclipse in those portions. There should be two points in those tracks where, if you went there, totality would last "zero seconds" or be instantaneous.

I'm not sure about Earth's rotation speed but I am sure it is one of yet more factors. There are probably better sources than me regarding this matter!