Editing Elongation (astronomy) (section)

==Of superior planets==
[[Superior planet]]s, [[dwarf planet]]s and [[asteroid]]s undergo a different cycle. After [[Conjunction (astronomy)|conjunction]], such an object's elongation continues to increase until it approaches a maximum value larger than 90° (impossible with inferior planets) which is known as ''[[opposition (astronomy)|opposition]]'' and can also be examined as a [[heliocentric]] conjunction with Earth.  This is archetypally very near 180°.  As seen by an observer on the superior planet at opposition, the Earth appears at conjunction with the Sun.  Technically, the point of opposition can be different from the time and point of maximum elongation.  Opposition is defined as the moment when the apparent [[ecliptic longitude]] of any such object versus the Sun (seen from earth) differs by (is) 180°; it thus ignores how much the object differs from the plane of the Earth's orbit.  For example, [[Pluto]], whose orbit is highly inclined to the essentially matching plane of the planets, has maximum elongation much less than 180° at opposition.  The six-word term "maximum apparent elongation from the sun" provides a fuller definition of '''elongation'''.

All superior planets are most conspicuous at their oppositions because they are near, or at, their closest to Earth and are also above the horizon all night. The variation in [[Apparent magnitude|magnitude]] caused by changes in elongation are greater the closer the planet's orbit is to the Earth's. [[Mars]]' magnitude in particular changes with elongation: it can be as low as +1.8 when in conjunction near aphelion but at a rare favourable opposition it is as high as &minus;2.9, which translates to seventy-five times brighter than its minimum brightness. As one moves further out, the difference in magnitude that correlates to the difference in elongation gradually falls. At opposition, the brightness of [[Jupiter]] from Earth ranges 3.3-fold; whereas that of [[Uranus]] &ndash; the most distant Solar System body visible to the [[naked eye]] &ndash; ranges by 1.7 times.

Since asteroids travel in an orbit not much larger than the Earth's, their magnitude can vary greatly depending on elongation. More than a dozen objects in the [[asteroid belt]] can be seen with 10×50 [[binoculars]] at an average opposition, but of these only [[Ceres (dwarf planet)|Ceres]] and [[4 Vesta|Vesta]] are always above the binocular limit of +9.5 when the objects at their worst points in their orbital opposition (smallest elongations).