Solar Angles

Rectilinear Project (Sun Path Diagram)

a two-dimensional graph of the sun's position in cartesian coordinates

Autumnal Equinox

sun overhead at equator

Vertical Equinox

sun overhead at equator

Winter Solstice

sun position (at equator) -altitude angle: 66.5 degrees -declination -23.5

Summer Solstice

sun position (at equator) -altitude angle: 90 degrees -declination:0

Stereographic Projection (Sun Path Diagram)

the format is like a fish-eye photograph of the sky pointed to the zenith directly above. Different diagram for various latitudes

Solar Noon

when the sun reaches the highest point in the sky

Solar Azimuth

(also called the solar bearing angle) is the angle along the horizon between the projected position of the sun and true (solar) south

Solar Altitude

-the angle between the horizon and the sun's position above the horizon -zenith angle= 90-solar altitude. Complement of altitude angle

Solar Declination

-the earth's axis of rotation which is tilted at 23.5. The tilt of the earth toward the sun changes over the year (june + 23.5 and december -23.5) -tilt is responsible for the seasons

Gnomonic Projection (Sun Path Diagrams)

Fixed height observer is at the center of the projection and edge odfthe shadow is marked for various time of the day and year. Low sun angle (sun rise and sunset) extend to infinity