[pysolar-discuss] Strange azimuth values

[Frank Lazzarini <flazzarini@xxxxxxxxx>]

Hi there,

when I run the following simulation I get really odd azimuth values. Well
at least they seem odd, if I understood the documentation correctly they
from ~90 over 0 to -90 degrees. When I run a simulation of an entire day I
get really odd values for azimuth.

from pysolar.solar import get_azimuth, get_altitude
from datetime import datetime
from pytz import timezone


latitude = 49.707524
longitude = 6.244362
year = 2015
month = 5
day = 10


def get_sun_position(latitude, longitude, time):
    alt = get_altitude(latitude, longitude, time)
    azi = get_azimuth(latitude, longitude, time)
    return alt, azi

tzinfo = timezone('Europe/Luxembourg')
today = datetime.now(tz=tzinfo)

for hour in range(0, 23):
    time = datetime(
        year,
        month,
        day,
        hour,
        0,
        tzinfo=tzinfo
    )
    alt, azi = get_sun_position(latitude, longitude, time)
    print("[{}] Altitude: {} Azimuth: {}".format(time, alt, azi))


Now when I run this I get the following values


[2015-05-10 00:00:00+00:25] Altitude: -22.817917957170042 Azimuth:
-180.91958537964064
[2015-05-10 01:00:00+00:25] Altitude: -21.35437669913535 Azimuth:
-196.28249041016966
[2015-05-10 02:00:00+00:25] Altitude: -17.460113361911073 Azimuth:
-210.88264446553194
[2015-05-10 03:00:00+00:25] Altitude: -11.530293822218377 Azimuth:
-224.33485353947378
[2015-05-10 04:00:00+00:25] Altitude: -4.041985922217601 Azimuth:
-236.6422942983795
[2015-05-10 05:00:00+00:25] Altitude: 4.721075310609919 Azimuth:
-248.0844855824365
[2015-05-10 06:00:00+00:25] Altitude: 13.916416678430616 Azimuth:
-259.1019578849806
[2015-05-10 07:00:00+00:25] Altitude: 23.540263468364685 Azimuth:
-270.25884449955726
[2015-05-10 08:00:00+00:25] Altitude: 33.162952138663265 Azimuth:
-282.2912788132876
[2015-05-10 09:00:00+00:25] Altitude: 42.311459924908625 Azimuth:
-296.2279541178277
[2015-05-10 10:00:00+00:25] Altitude: 50.279286820496274 Azimuth:
-313.49311577994877
[2015-05-10 11:00:00+00:25] Altitude: 55.94436234658116 Azimuth:
-335.49523632286264
[2015-05-10 12:00:00+00:25] Altitude: 57.89747249155467 Azimuth:
-1.6026287381770885
[2015-05-10 13:00:00+00:25] Altitude: 55.45948436540424 Azimuth:
-27.402783821691315
[2015-05-10 14:00:00+00:25] Altitude: 49.46294168127422 Azimuth:
-48.82724611999379
[2015-05-10 15:00:00+00:25] Altitude: 41.31880137304067 Azimuth:
-65.63086306581897
[2015-05-10 16:00:00+00:25] Altitude: 32.09659468953159 Azimuth:
-79.28835550065156
[2015-05-10 17:00:00+00:25] Altitude: 22.46665426651643 Azimuth:
-91.18090530087704
[2015-05-10 18:00:00+00:25] Altitude: 12.887187896956561 Azimuth:
-102.29565250233105
[2015-05-10 19:00:00+00:25] Altitude: 3.8032148272317357 Azimuth:
-113.34291810798067
[2015-05-10 20:00:00+00:25] Altitude: -4.854352153303335 Azimuth:
-124.86962574438837
[2015-05-10 21:00:00+00:25] Altitude: -12.152382809733522 Azimuth:
-137.2976741424302
[2015-05-10 22:00:00+00:25] Altitude: -17.83265833925366 Azimuth:
-150.87639859009437



Any ideas?

-- 

*Frank Lazzarini*
*Email:* flazzarini@xxxxxxxxx  *Phone:* +352 621 314 430
*Blog:*   http://www.gefoo.org   *LinkedIn:*
http://www.linkedin.com/pub/frank-lazzarini/1a/a30/112