Sun Position Not Correct For Certain Days of the Year


#1

I am studying the shadow casts by buildings throughout the year and I noted that during certain days of the year the sun is at the wrong position for location 14.5N, 121E and UTC+8:00. At this location, the sun should always be at the south of the building casting shadow to the north side. I noted that at 12:00NN of 4/29 the sun is above the building and no shadow is cast on the ground. Before this day, the sun is at the south side as it should be. After 4/29 the sun starts to move north of the building casting shadow to the south side ground. This occurs until 8/14 where the sun is again above the building. From this day onward, the sun moves to the south.

I uploaded a pdf file of the screen captures showing the above shadow positions.

SunPosition.pdf (597.1 KB)

My question is if there is any adjustment I can do to correct this. Any advice or guidance is highly appreciated. Thanks.

dannyllim


#2

It’s been a while since I took celestial navigation, but isn’t 14.5N south of the Tropic of Cancer? So for a few months around the Summer Solstice the sun will be north of your location and will cast shadows to the south?

M


#3

Yep. Tropic of Cancer=23°26′13.6″ says Wikipedia.


#4

I made a movie, of looking straight up, with south on the left and north on the right. It shows that the sun is towards north from April 29th to August 14th. The recording is every day of 2018, and happens to show that you’ll get two solar eclipses that year.


#5

You’ll find the United States Naval Observatory along with SketchUp do not agree with you.

Visit
USNO > Data Services
http://www.usno.navy.mil/USNO/astronomical-applications/data-services

Positions of Selected Celestial Objects > Altitude and Azimuth of the Sun or Moon During One Day
http://aa.usno.navy.mil/data/docs/AltAz.php

USNO_Alt_Az_Table_July_1_2016.pdf (85.2 KB)


#6

Thanks for correcting me. Appreciate the information provided by everyone who responded.

dannyllim