annular solar eclipse
Annular solar eclipse of 21 May 2031
At greatest eclipse the Moon's disc spans 0.4975° against the Sun's 0.5270° — a ratio of 0.9439. Because the Moon appears smaller, it cannot cover the Sun, and a ring of sunlight is left around it. That is what makes this eclipse annular rather than total.
Where you can see it
The shadow crosses Africa, the Indian Ocean, Central and South Asia, South-East Asia and the Pacific and Australia and the south-west Pacific. Only along the central line does the Moon cover the Sun completely; a few hundred kilometres either side and it is a partial eclipse, which looks nothing like the same event.
How much is covered, and where
Sorted by how much of the Sun disappears. Below about 40% nothing looks wrong to the naked eye — the Sun is so bright that losing a third of it changes very little. Never look without a proper solar filter regardless.
| City | Covered | Maximum (UTC) | Sun altitude |
|---|---|---|---|
| Singapore | 82% | 08:51 | 31° |
| Nairobi | 75% | 05:36 | 29° |
| Mumbai | 60% | 07:26 | 85° |
| Johannesburg | 47% | 05:25 | 8° |
| Cape Town | 36% | 05:27 | below horizon |
| Delhi | 29% | 07:41 | 75° |
| Hong Kong | 27% | 08:50 | 27° |
| Dubai | 24% | 06:42 | 68° |
| Jeddah | 15% | 06:06 | 45° |
| Perth | 5% | 08:46 | 6° |
| Luxor | 2% | 06:04 | 39° |
Not visible at all from Brussels, Antwerp, Ghent, Bruges, Liège, Leuven, Charleroi, Amsterdam, Rotterdam, The Hague, Utrecht, Eindhoven, Luxembourg, London, Manchester, Birmingham, Glasgow, Edinburgh, Cardiff, Belfast, Dublin, Paris, Lyon, Marseille, Berlin, Munich, Hamburg, Cologne, Zurich, Vienna, Prague, Warsaw, Copenhagen, Stockholm, Oslo, Helsinki, Reykjavík, Madrid, Barcelona, Lisbon, Rome, Milan, Athens, Istanbul, New York, Boston, Washington, D.C., Miami, Atlanta, Chicago, Houston, Dallas, Denver, Phoenix, Los Angeles, San Francisco, Seattle, Toronto, Montreal, Vancouver, Mexico City, São Paulo, Buenos Aires, Santiago, Cairo, Cádiz, Málaga, Tangier, Benghazi, Tokyo, Seoul, Sydney, Melbourne, Brisbane, Auckland.
Greatest eclipse falls at 8.92°, 71.73° — the point where the axis passes closest to Earth's centre. The central line is computed from the Sun–Moon axis intersected with the geoid, and agrees with the reference coordinates to within a tenth of a kilometre.
Why eclipses come in seasons
The Moon's orbit is tilted about 5° to the ecliptic, so at most new and full moons it passes above or below the alignment. An eclipse needs the syzygy to coincide with the Moon being near one of the two nodes where the orbits cross. At this eclipse the Moon's ecliptic latitude was -0.179° — close enough to zero for the shadow to connect.
Times computed from VSOP87 and an ELP-derived lunar theory, validated against NOVAS and JPL Horizons to within one arcminute. See the alignment for yourself in the live simulation.