Asteroid 20 Massalia will be well placed, lying in the constellation Aries, well above the horizon for much of the night.

Regardless of your location on the Earth, 20 Massalia will reach its highest point in the sky around midnight local time.

From Cambridge, it will be visible between 19:38 and 05:18. It will become accessible at around 19:38, when it rises to an altitude of 21° above your eastern horizon. It will reach its highest point in the sky at 00:28, 61° above your southern horizon. It will become inaccessible at around 05:18 when it sinks below 21° above your western horizon.

The geometry of the alignment

This optimal positioning occurs when it makes its closest approach to the point in the sky directly opposite to the Sun – an event termed opposition. 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 20 Massalia passes opposition, it also makes its closest approach to the Earth – termed its perigee – making it appear at its brightest in the night sky. This happens because when 20 Massalia lies opposite to the Sun in the night sky, the solar system is lined up so that 20 Massalia, the Earth and the Sun lie in a straight line with the Earth in the middle, on the same side of the Sun as 20 Massalia.

On this occasion, 20 Massalia will pass within 1.237 AU of us, reaching a peak brightness of magnitude 8.8. Nonetheless, even at its brightest, 20 Massalia is a faint object beyond the reach of the naked eye; binoculars or a telescope of moderate aperture are needed.

Finding 20 Massalia

The chart below indicates the path of 20 Massalia across the sky around the time of opposition.

It was produced using StarCharter and is available for download, either on dark background, in PNG, PDF or SVG formats, or on a light background, in PNG, PDF or SVG formats.