Gegenschein, like the zodiacal light, is caused by sunlight reflecting off interplanetary dust, but it appears directly opposite the Sun in the sky, centered at the antisolar point. Gegenschein forms a slightly brighter, oval-shaped spot about 8-10° across within the dimmer band of the zodiacal light. Gegenschein is even more difficult to detect than the zodiacal light, requiring a perfectly dark sky and the use of the averted vision.