We DON'T have seasons because the Earth-Sun distance varies!
We have seasons because the Earth's axis of rotation is tilted.
The change in angle of illumination means the Sun's altitude changes with the
seasons. Its daily path varies as in this illustration.
Over the course of a year, the Sun appears to circle
the celestial sphere due, to our motion along our orbit.
As the Sun crosses the celestial sphere, it passes
above and below the celestial equator.
Since our orbit lies in the Sun's ecliptic, the Sun's path across the celestial sphere
is also called the ecliptic -- see
1* and
2*.
When the Sun is the farthest north, at our summer solstice,
it is directly over the Tropic of Cancer. When the Sun is the farthest south,
at our winter solstice, it lies directly over the Tropic of Capricorn.
At the equinoxes, the Sun is directly over the equator.
This occurs at the midpoints between the solstices.