Indicate sun's position on horizon & number of day light hours by monthvariation?

Answer 1

Check out the U. S. Navy's resources. They have that information for way back and into the future.

http://aa.usno.navy.mil/data/docs/RS_OneDay.html

http://www.geosummit.org/resource/suninfo/astronomicaldata.html

http://www.almanac.com/rise/

http://www.itlnet.net/Research.asp

Good luck!

Answer 2

While there are websites that do this, you can do a pretty good job with a few simple equations, The two things you need are you latitude and the Sun's declination. You can look up your latitude (Lat) in an atlas or on Google Earth. The Sun's declination is surprisingly simple to estimate. It moves nearly sinusoidally between + and - 23.5 degrees. Take the number of days since the vernal equinox (call that d) and the declination of the Sun is:

Dec = 23.5 sin( d * 360/365)

Once you ahve the declination, the hours of sunlight is:

H = acos(-tan(Lat) tan(Dec))/7.5

For example, at 35 degrees north latitude (Lat = +35) on November 1 (d = 225) there are:

H = acos(tan(-35 deg) * tan(23.5 * sin(225*360/365)))/7.5 = acos(-0.700 * sin(23.5 * -0.668))/7.5 = 10.48 hours = 10 hours 30 minutes. To this, add about 6 minutes for atmospheric refraction and to allow for the upper limb of the Sun to meet the horizon and you have 10:40. The actual number is 10:47 so the approximation is very good.

As far as where the Sun rises or sets, call the angle, measured from north S then:

S = arccos(sin(Dec)/cos(Lat))

At my location, Lat = +35 deg on the summer solstice (Dec = +23.5 deg) the Sun sets at 60.9 degrees from north.

Answer 3

Hi. In the Northern hemisphere the Sun rises and sets more to the south as you approach the first day of winter, then reverses and moves farther north on the horizon until the first day of summer. The number of daylight hours is least at the first day of winter (around December 21st) and most at the first day of summer (around Jun 21st). Hope this makes sense to you.