Asteroid 29 Amphitrite will be well placed, lying in the constellation Aquarius, 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 around midnight local time.
From Seattle, it will be visible between 22:03 and 04:18. It will become accessible around 22:03, when it rises to an altitude of 22° above your south-eastern horizon. It will reach its highest point in the sky at 01:11, 35° above your southern horizon. It will become inaccessible around 04:18 when it sinks below 22° above your south-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 1.482 AU of us, reaching a peak brightness of magnitude 9.0. Nonetheless, even at its brightest, 29 Amphitrite is a faint object beyond the reach of the naked eye; binoculars or a telescope of moderate aperture are needed.
Finding 29 Amphitrite
The chart below indicates the path of 29 Amphitrite across the sky around the time of opposition.
The position of 29 Amphitrite at the moment of opposition will be as follows:
|Asteroid 29 Amphitrite||23h16m20s||6°29'S||Aquarius||9.0|
The coordinates above are given in J2000.0.
|The sky on 28 October 2021|
22 days old
All times shown in PDT.
The circumstances of this event were computed from orbital elements made available by Ted Bowell of the Lowell Observatory. The conversion to geocentric coordinates was performed using the position of the Earth recorded in the DE430 ephemeris published by the Jet Propulsion Laboratory (JPL).
The star chart above shows the positions and magnitudes of stars as they appear in the Tycho catalogue. The data was reduced by the author and plotted using PyXPlot. A gnomonic projection of the sky has been used; celestial coordinates are indicated in the J2000.0 coordinate system.
© NASA/Galileo 1993. Pictured asteroid is 243 Ida.