Maximum Elongation of Inner Planets
From the Earth’s perspective, the inner planets seem to stay near the sun. This is because it orbits the inside of the earth.So the inner planets can not be seen in the middle of the night.
Elongation is the angle that the inner planet makes with the sun. As far as possible, the angle is ‘maximum elongation’.The maximum elongation of Mercury is about 24 °, and the maximum elongation of Venus is about 48 °. This tells us that Mercury is orbiting more inside than Venus.