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Re: solar calculation



How can we calculate the angle of the sun, above the horizon, at a
specific location ( a city for example) on the dates of Dec 21st, March
21st, June 21st, and Sept 21st?

Let's star over. I got that very wrong

I'll assume you mean at local solar noon, the time when its altitude, A,
(the angle above a true horizon) is maximum for that day. The obliquity
of the ecliptic, I, is approximately 23-1/2 degrees. For an observing
location at latitude L, these quantities (in degrees) are related by:

Date formula

Summer solstice A = 90 - L + I = 113.5 - L

Equinoxes (both) A = 90 - L

Winter solstice A = 90 - L - I = 66.5 - L

All of these are calculated above the southern horizon. If the answer
is greater than 90 degrees (unlikely in Sweden, unless you have colonies
I don't know about) then the Sun is still highest at noon, but it is
north of the zenith.

I can't imagine what I was thinking when I wrote down those other
formulae. I apologize. I'd better get some sleep!

Leigh