Geminiano Montanari

Italian astronomer

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June 30, 2026

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Geminiano Montanari was an Italian astronomer who, in 1670, was the first European to note the light variation of the star Algol. Algol is an eclipsing binary star, meaning its apparent brightness changes as one star passes in front of the other. Montanari's observation was a significant early step in understanding variable stars.12

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Algol
…light variation was the Italian Geminiano Montanari in 1670; the English astronomer John Goodricke measured the cycle (69 hours) in 1782 and suggested partial eclipses of the star by another body as a cause, a hypothesis proved correct in 1889. The comparatively long duration of the eclipse shows that the…
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…light variation was the Italian Geminiano Montanari in 1670; the English astronomer John Goodricke measured the cycle (69 hours) in 1782 and suggested partial eclipses of the star by another body as a cause, a hypothesis proved correct in 1889. The comparatively long duration of the eclipse shows that the…
Read More