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Old 04-17-2014, 02:24 PM
 
Location: North West Northern Ireland.
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Can still see hills..
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Sunrise, Sunset, and Twilight! What are your city's times for today?-image.jpg  

 
Old 04-17-2014, 02:28 PM
 
Location: North West Northern Ireland.
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...
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Sunrise, Sunset, and Twilight! What are your city's times for today?-image.jpg  
 
Old 04-17-2014, 05:12 PM
 
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Still dark like when the sun 3-4 deg. below horizon, 2 mins. after sunrise time
 
Old 04-17-2014, 08:39 PM
 
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Quote:
Originally Posted by dunno what to put here View Post
Ditto. March-early May and August-late October are the boring sunset times IMO, further reinforcing my opinion that I would never want to live somewhere with equal daylight.
Maybe I can define (for spring/late summer 50s lat in Europe), "boring" means sunrise later than 6.00
 
Old 04-17-2014, 08:53 PM
 
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Quote:
Originally Posted by Hiromant View Post
Sunrise: 7:22
Sunset: 19:00

Day length: 11 h 38 min
Highest sun angle: 28°

Day length is similar for everyone now and I don't really have a sense that it's "dark" yet. Boy that'll change in a month though.
I do in Octobers or so. It's the start of wet "season" till March, also the sunsets are earlier. Even it can be pitch black at 6.25 (sunset 6.05). It also the sun angle get weaken.
 
Old 04-17-2014, 09:43 PM
 
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Quote:
Originally Posted by EricS39 View Post
I have a solar astronomy app I constructed in Microsoft excel and it is very accurate for some locations and off by 2-3 minutes in others. When it's off by more than that I get mad that my model is off.

I think a lot of it is land altitude or obstacles blocking view of the sun that my model doesn't adjust for, and also some calendar days are more off because the standard formula for angle of declination is only a good approximation but it also needs adjusting

The whole arc sine of (x-81)/91.25 times sine(23.45) because the elapsed days between solstices are not symmetric

But my model should still be accurate within +- 1 to 3 minutes and often times it's spot on

It is absolutely spot on that if I graphed my data you would not be able to distinguish the margin of error against exact data when eyeballing it
I've made in the excel last Wednesday. And finally found that the sun declination given by the sine (times 23.45) is close to the actual sun declination (just google), max difference is about half a degree
 
Old 04-18-2014, 01:56 AM
 
Location: North West Northern Ireland.
20,633 posts, read 23,890,394 times
Reputation: 3107
6:18
8:38
 
Old 04-18-2014, 04:50 AM
 
4,658 posts, read 3,660,811 times
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Quote:
Originally Posted by Mac15 View Post
6:18
8:38
Soon your sunrise times being earlier than mines...
 
Old 04-18-2014, 04:54 AM
 
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Longyearbyen's sun rose at 1:45 CEST 4/18 (23:45 GMT 4/17) and doesn't set until 0:31 CEST 8/25 (22:31 GMT 8/24) !!!
 
Old 04-18-2014, 05:06 AM
 
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Quote:
Originally Posted by Mac15 View Post
Starting to get bored of the pre 9pm sunsets. Yawwwwnnnn

8:28pm.
Do you also bored of the post 6am sunrises? Its roughly equivalent for a 1:30 solar noon
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