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THE SUNRISE / SUNSET COMPUTER

For Any Latitude and Any Angle of Elevation North of the Equator

FIRST THINGS FIRST:
What year are you interested in:
Enter all 4 digits, please!
What day of March does the previous vernal equinox to the date you are interested in fall on?
March
(eg, if you are interested in an Azimuth for a date in Jan, Feb, or early Mar of 2000,
you would use the vernal equinox date for 1999.
Just leave this as is if you are unsure)

AZIMUTH CALCULATOR

 

DAY CALCULATOR

Example: At what azimuth (degrees from True North) will the sun rise on the Summer Solstice at my home with a level horizon?   Example: I am in a new stone ring at 40 degrees north latitude, and there is a notch in the hills at an azimuth of 120 Degrees with an angle of elevation to the bottom of the notch of 4 degrees.
    On what day(s) of the year will the sun rise or set there?
     
ENTER your latitude: degrees North
 
ENTER the angle of elevation to the horizon:
degrees
ENTER month and date you are interested in:
 
or
It is important to hit the <Start Over> button for each new calculation for the most reliable results.

 
ANSWER:
The sun will rise degrees
from North on the day you specified.
The sun will set degrees
from North on the day you specified.
The Declination on that day will be degrees from the celestial equator.
 
ENTER your latitude: degrees North
 
ENTER the angle of elevation to the horizon:
degrees
ENTER the azimuth of the sunrise/sunset:
degrees from North
 
or
It is important to hit the <Start Over> button for each new calculation for the most reliable results.

 
ANSWER:
The sun will rise/set on
at the azimuth you specified.
The Declination on that day will be
degrees from the celestial equator.
 

DISCUSSION

AZIMUTH CALCULATION
The answer is rounded to the nearest 1/100 of a degree.

DAY CALCULATION
Because of rounding errors and uncertainty with the date of the Solstices, the date(s) given are accurate to within a day on either side.*
*Because of the very small changes in azimuth around the Solstices, solstice azimi are accurate for several days on either side of the solstice.

If you want to download this script, it will work fine without having to be connected to the Internet, so you can take your laptop into the field and use this program there. In Internet Explorer, go to <Find> on the menu line. Go to <Save As>, and save as <Web Archive>. On your computer, double click on the <Sunfinder> icon, and it's ready to use. If you get answers that do not make sense, clear the script by reloading the page. Please let Mid-Atlantic Geomancy know how it worked for you.

 

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