© NASA/Dawn 2015

1 Ceres at opposition

Dominic Ford, Editor
From the Dwarf Planets feed

Objects: 1 Ceres
Please wait
Loading 0/4
Click and drag to rotate
Mouse wheel to zoom in/out
Touch with mouse to dismiss
The sky at

1 Ceres will be well placed in the sky, in the constellation Taurus. It will be visible for much of the night, reaching its highest point in the sky around midnight local time.

From Fairfield, it will be visible between 18:39 and 04:44. It will become accessible around 18:39, when it rises to an altitude of 22° above your eastern horizon. It will reach its highest point in the sky at 23:40, 65° above your southern horizon. It will become inaccessible around 04:44 when it sinks below 22° above your western horizon.

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.

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 1.76 AU, and its disk will measure 0.0 arcsec in diameter, shining at magnitude 7.2. 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.

A chart of the path of 1 Ceres across the sky in 2021 can be found here, and a chart of its rising and setting times here.

The position of 1 Ceres at the moment it passes opposition will be:

Object Right Ascension Declination Constellation Magnitude Angular Size
1 Ceres 04h15m20s +16°44' Taurus 7.2 0.0"

The coordinates above are given in J2000.0.

The sky on 27 November 2021
Twilight ends
Twilight begins

23-day old moon
Waning Gibbous


23 days old

Rise Culm. Set
Mercury 06:54 11:36 16:19
Venus 10:21 14:47 19:12
Moon 23:02 06:00 12:58
Mars 05:32 10:32 15:33
Jupiter 12:03 17:15 22:27
Saturn 11:17 16:10 21:04
All times shown in EST.


The circumstances of this event were computed using the DE430 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.

Related news

27 Nov 2021  –  1 Ceres at opposition
22 Jul 2022  –  1 Ceres at solar conjunction
10 Dec 2022  –  1 Ceres at perihelion
21 Mar 2023  –  1 Ceres at opposition

Image credit

© NASA/Dawn 2015






Color scheme