136472 Makemake at opposition

2016 Mar 22

Dominic Ford – originally published on In-The-Sky.org

136472 Makemake will be well placed for observation, in the constellation Coma Berenices. It will be visible for much of the night, reaching its highest point in the sky at around midnight local time.

From London (click to change), it will be visible all night. It will become visible at around 19:33 (GMT) as the dusk sky fades, 25° above your eastern horizon. It will be lost to dawn twilight at around 04:36, 41° above your western horizon.

136472 Makemake in coming weeks

Over the weeks following its opposition, 136472 Makemake will reach its highest point in the sky four minutes earlier each night, gradually receding from the pre-dawn morning sky while remaining visible in the evening sky for a few months.

A chart of the path of 136472 Makemake across the sky in 2016 can be found here, and a chart of its rising and setting times here.

The position of 136472 Makemake at the moment it passes opposition will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
136472 Makemake 12h55m20s +25°44' Coma Berenices 16.9 0.0"

The coordinates above are given in J2000.0.

The geometry of the solar system

This optimal positioning occurs when 136472 Makemake is almost directly opposite the Sun in the sky. Since the Sun reaches its greatest distance below the horizon at midnight, the point opposite to it is highest in the sky at the same time.

At around the same time that 136472 Makemake passes opposition, it also makes its closest approach to the Earth – termed its perigee – making it appear at its brightest and largest.

This happens because when 136472 Makemake lies opposite the Sun in the sky, the solar system is lined up so that 136472 Makemake, the Earth and the Sun form a straight line with the Earth in the middle, on the same side of the Sun as 136472 Makemake.

In practice, however, 136472 Makemake orbits much further out in the solar system than the Earth – at an average distance from the Sun of 45.73  times that of the Earth, and so its angular size does not vary much as it cycles between opposition and solar conjunction.

On this occasion, 136472 Makemake will lie at a distance of 51.57 AU, and reach a peak brightness of magnitude 16.9. Even at its closest approach to the Earth, however, 136472 Makemake is so distant from the Earth that it is not possible to distinguish it as more than a star-like point of light.

The details of this observing event were provided courtesy of In-The-Sky.org