The ring of light caused by sunlight refracted by ice crystals hung in the sky for almost an hour before it finally faded and disappeared.
Some Ethiopians say it last appeared in 1991 before a military regime fell.
But the BBC’s Elizabeth Blunt in Addis Ababa says there is little chance it could augur change this time.
She says the overwhelming majority of candidates are from the government party.
Churchgoers who had flocked to see the visiting Patriarch of Alexandria, Pope Shenouda, acclaimed the phenomenon as a miracle, or at least a sign of a blessing from God.
Thank you, God, for revealing a sign
Abuna Paulos, Patriarch of Ethiopia
Pope Shenouda himself believed it was a signal from above.
“We accept any sign from God to encourage us in our way,” he said, “and confirm that we are going right in our way.”
Abuna Paulos, the Patriarch of Ethiopia, added his voice to those who believe in signs from God.
“If God reveals himself from the sky,” he told a press conference, “we believers do not get surprised. We only rejoice and double our efforts to thank God. Thank you, God, for revealing a sign.”
But others looked for more secular implications.
Older people in Addis Ababa remember seeing the ring around the sun once before – in the last days of the Derg, the despised military dictatorship, just before its leader Mengistu Haile Mariam fled to Zimbabwe.
But there is little prospect of the government falling in these elections.
The opposition winners of the controversial elections in 2005 in urban areas never took their seats and did not stand again.
The most successful of the other opposition parties pulled out, complaining of intimidation and our correspondent says the results are almost certain to consolidate the ruling party’s hold on power.
Results have not been published yet but an election official said turnout had been massive.
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