Turn off the daylight display and turn on the horizon display.
Click on the "Settings" button and be sure that
Orientation is set to Local. Scroll in azimuth until you are
looking due west (azimuth = 270°). Scroll up and down
in altitude until the horizon is about a quarter of the way
from the bottom to the top of the display. Set the date for
March 21 (approximately the vernal equinox) and then
step back and forth in time until you find the time of sunset.
Using the Selection Tool, point at the Sun and right click.
Then click on the Info Window and record the azimuth
of the Sun at sunset. Repeat for June 21, September 21,
and December 21. Calculate the difference between
the most northerly and most southerly sunset azimuths.
Set the geographical location to Edinburgh. Again find the
azimuth of sunset for March 21, June 21, and September 21.
Calculate the difference between most northerly and
southerly sunset azimuths. Compare your results for the
two locations. How do you think the difference in azimuth
would change if you went north to the arctic circle or
south to the equator? What impact do these changes have
on the severity of the seasons at different latitudes?
