While the changes in the motion of the sun are the most dramatic effects of Earth's revolution, our ability to observe the stars and planets is affected as well. This is due to the sun's apparent motion through the celestial sphere along the ecliptic.

Constellations are sometimes classified as winter or summer constellations depending on the season in which they are best observed. The general rule is that the farther a constellation is from the sun, the longer it is visible at night.

So when is the best time to see Scorpius? Not during the month of November, when the sun passes through it; but six months later, when the sun is on the other side of the sky.

This rule works best for constellations near the celestial equator, because their distance from the sun varies the most with the changing seasons. The farther a star is from the celestial equator, the more difficult it is to group it into a particular observing season.

The motion of the moon and planets is more complex. Their apparent positions change due to Earth's revolution but are also affected by the true motion of their orbits around the sun (or Earth, in the case of the moon).