Ceres, the only dwarf planet located in the main asteroid belt between Mars and Jupiter, will reach opposition—on the opposite side of the sun in our sky—on October 2, 2025.
Ceres at opposition in 2025
When to see in 2025: Ceres will be best visible from late September to mid-October in 2025 when the dwarf planet rises in the east around sunset and is visible all night. After opposition, Ceres will disappear from the morning sky gradually as it rises and sets around four minutes earlier each day. Three months after opposition, i.e., in early January 2026, Ceres will be visible in the evening sky only as it sets around midnight.
How to identify: Ceres will be too dim to be visible with the unaided eye even around its October 2 opposition. You will need a telescope or a good binoculars to see it. It will appear as a star-like point of light, even through a telescope. You will see it move in front of the stars from night to night. It will be visible around 15° below of Saturn in the southeastern evening sky around its October 2 opposition.
Closest approach of Ceres in 2025: Ceres will be closest to Earth around its October 2 opposition, when Earth passes between the sun and Ceres. At its closest approach, Ceres will be 1.96 AU, or 293 million kilometers, from Earth.
Brightness at opposition: At its October 2 opposition, Ceres will be brightest for 2025 and will shine with a magnitude of +7.6.
Constellation at opposition: At its October 2 opposition, Ceres will be located in the constellation Cetus, the Whale.
What does “Ceres at opposition” mean?
Ceres reaches opposition when Earth passes between the sun and the dwarf planet Ceres.
As the sun and Ceres are on opposite sides of the Earth during opposition, they appear on opposite sides, or 180° apart, in our sky.
As a result, Ceres rises in the east when the sun sets in the west, reaches its highest point in the sky around midnight when the sun is below your feet, and sets in the west when the sun rises in the east.
How often does Ceres reach opposition?
Our Earth’s orbit is smaller and faster than Ceres’ orbit. While Earth takes about 365 days to orbit the sun, Ceres takes about 1682 days to do so.
Ceres reaches opposition once every 15.6 months because it takes our Earth an average of 467 days (15.6 months) to catch up with Ceres, i.e., to align the sun, Earth, and Ceres in a straight line.
When Ceres is near its perihelion, our Earth takes longer than usual (around 16 months) to catch up with Ceres because Ceres travels faster in that part of its orbit (according to Kepler’s second law of planetary motion).
And when Ceres is near its aphelion, our Earth takes less time than usual (around 15 months) to catch up with Ceres because Ceres travels slower in that part of its orbit.
Ceres’ opposition dates
Here are the dates of Ceres’ opposition from 2025 to 2029, according to NASA:
| Date of opposition | Distance (AU) |
|---|---|
| October 2, 2025 | 1.96 |
| January 7, 2027 | 1.63 |
| May 7, 2028 | 1.69 |
| August 11, 2029 | 1.98 |
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