Researchers use historic accounts of a rare red aurora over Kyoto in the 18th century to support calculations of the strength of the associated magnetic storm which could be 3–10% stronger than an 1859 storm, considered the greatest storm in the past 200 years.

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Researchers use historic accounts of a rare red aurora over Kyoto in the 18th century to support calculations of the strength of the associated magnetic storm which could be 3–10% stronger than an 1859 storm, considered the greatest storm in the past 200 years.