Asteroid 29 Amphitrite at opposition

2019 Oct 13

Asteroid 29 Amphitrite will be well placed for observation, lying in the constellation Pisces, well above the horizon for much of the night.

Regardless of your location on the Earth, 29 Amphitrite will reach its highest point in the sky at around midnight local time.

From London, it will be visible between 20:01 and 05:15. It will become accessible at around 20:01, when it rises 21° above your eastern horizon, and then reach its highest point in the sky at 00:40, 49° above your southern horizon. It will become inaccessible at around 05:15 when it sinks to 22° 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 29 Amphitrite 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 29 Amphitrite lies opposite to the Sun in the night sky, the solar system is lined up so that 29 Amphitrite, the Earth and the Sun lie in a straight line with the Earth in the middle, on the same side of the Sun as 29 Amphitrite.

On this occasion, 29 Amphitrite will pass within 1.412 AU of us, reaching a peak brightness of magnitude 8.7. Nonetheless, even at its brightest, 29 Amphitrite is a faint object beyond the reach of the naked eye or binoculars; a telescope of moderate aperture and a good star chart are needed.

Finding 29 Amphitrite

The star charts below mark the path of 29 Amphitrite across the sky around the time of its opposition.

This star chart is also available to download:

Light-on-dark PNG image PDF document
Dark-on-light PNG image PDF document

The exact position of 29 Amphitrite at the moment of opposition will be as follows:

Object Right Ascension Declination Constellation Magnitude
Asteroid 29 Amphitrite 01h05m10s +11°21' Pisces 8.7

The coordinates above are given in J2000.0.

This entry in the observing calendar was provided by