The Moon's axial tilt with respect to the ecliptic is only 1.5427°,[8][77] much less than the 23.44° of Earth. Because of this, the Moon's solar illumination varies much less with season on the Moon, and topographical details play a considerably more crucial role in seasonal effects on localities on the Moon.[78] From images taken by Clementine in 1994, it appears that four mountainous regions on the rim of the crater Peary at the Moon's north pole may remain illuminated for the entire lunar day, creating peaks of eternal light. No such regions exist at the south pole. Similarly, there are places that remain in permanent shadow at the bottoms of many polar craters,[79] and these "craters of eternal darkness" are extremely cold: Lunar Reconnaissance Orbiter measured the lowest summer temperatures in craters at the southern pole at 35 K (−238 °C; −397 °F)[80] and just 26 K (−247 °C; −413 °F) close to the winter solstice in the north polar crater Hermite. This is the coldest temperature in the Solar System ever measured by a spacecraft, colder even than the surface of Pluto.[78] Average temperatures of the Moon's surface are reported, but temperatures of different areas will vary greatly depending upon whether they are in sunlight or shadow.[81]