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posted by [personal profile] ptc24 at 09:39am on 22/09/2010
Happy birthday [personal profile] emperor!

Which reminds me, equinox tomorrow. I looked it up, it's at 03:09 UTC, which I guess is when the sun checks into the southern hemisphere, somewhere to the east of Indonesia, I think. Or in less anthropomorphic, geocentric terms, when the equator crosses the line from the centre of the sun to the centre of the Earth, with the intersection being somewhere to the east of Indonesia.

Anyway, the rate at which the days (in the (shrinking regions of the) northern hemisphere (where they still have days)) will be getting shorter will start slowing down, so we have that to celebrate. Or if you like darkness, it's soon going to be the dark half of the year. Either way, it's good news.
There are 4 comments on this entry. (Reply.)
 
posted by [identity profile] keirf.livejournal.com at 09:24am on 22/09/2010
Always depressing from my point of view. From now the Tampere nights are going to be longer than the Cambridge nights.

http://www.gaisma.com/en/location/tampere.html
http://www.gaisma.com/en/location/peterborough.html

These are interesting, especially the "sun's path in the sky" charts, which show that the real problem I face here in Finland in the winter is that although there is supposedly 4 hours of daylight the sun barely manages to limp above the horizon, and is therefore blocked by the trees and apartment buildings.
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posted by [personal profile] ptc24 at 09:38am on 22/09/2010
Well, it depends on what you mean by "nights", if you exclude civil twilight, then the cross-over seems to be Oct 6:

http://www.wunderground.com/history/airport/EFTP/2010/10/6/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA
http://www.wunderground.com/history/airport/EGUN/2010/10/6/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA

...but as you say, the low sun in Findland means that the quality of daylight during daylight hours is low, so I guess it all balances out somehow.
 
posted by [identity profile] keirf.livejournal.com at 12:09pm on 22/09/2010
Civil twilight may be when the sun is more than 5° below the horizon, but this doesn't take in to account that there are always 15m tall trees within 20 meters of you in Finland. As a result although the sky is bright blue, it's dark and gloomy down on the ground from about 15 minutes before sunset. A bit like when you're in a deep valley in the mountains.
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posted by [personal profile] emperor at 11:19am on 22/09/2010
Thank you :)

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