From Cambridge, it will be visible in the morning sky, becoming accessible around 20:22, when it rises to an altitude of 21° above your eastern horizon. It will then reach its highest point in the sky at 01:22, 63° above your southern horizon. It will be lost to dawn twilight around 05:42, 28° above your western horizon.
1 Ceres opposite the Sun
This optimal positioning occurs when 1 Ceres 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 1 Ceres 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 1 Ceres lies opposite the Sun in the sky, the solar system is lined up so that 1 Ceres, the Earth and the Sun form a straight line with the Earth in the middle, on the same side of the Sun as 1 Ceres.
In practice, however, 1 Ceres orbits much further out in the solar system than the Earth – at an average distance from the Sun of 2.77 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, 1 Ceres will lie at a distance of 1.60 AU, and its disk will measure 0.0 arcsec in diameter, shining at magnitude 7.0. Even at its closest approach to the Earth, however, it is not possible to distinguish it as more than a star-like point of light without the aid of a telescope.
1 Ceres in coming weeks
Over the weeks following its opposition, 1 Ceres 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.
The position of 1 Ceres at the moment it passes opposition will be:
|Object||Right Ascension||Declination||Constellation||Magnitude||Angular Size|
|1 Ceres||12h27m10s||+15°37'||Coma Berenices||7.0||0.0"|
The coordinates above are given in J2000.0.
|The sky on 20 March 2023|
28 days old
All times shown in EDT.
The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.
|20 Mar 2023||– 1 Ceres at opposition|
|20 Nov 2023||– 1 Ceres at solar conjunction|
|05 Jul 2024||– 1 Ceres at opposition|
|14 Feb 2025||– 1 Ceres at solar conjunction|