Problem 4: The planets orbit the Sun in ellipses that are very close to circles.
They all are in the same plane, so on the sky they lie on the ecliptic.
Notice that the outer planets can appear anywhere on the ecliptic, but that the
inner worlds (Mercury and Venus) are only seen within a certain angular distance
from the Sun. The maximum angular distance from the Sun, as seen from the Earth, is
call their greatest elongation.
Draw the celestial sphere and place the Sun on the meridian 30 degrees above the
horizon. Draw Venus' position at the time of maximum elongation of 47
degrees.
Problem 5: You live at latitude 50 degrees and are looking out your
western window as the Sun sets on the horizon. Mark the celestial equator
and Venus at its greatest elongation of 47 degrees from the Sun.
