Abstract
THE EARLIEST DAY-LIGHT OBSERVATIONS OF STARS.—In No. 2616 of the Astronomische Nachrichten Prof. Winnecke has an interesting note on the question, Who first observed stars in full daylight? The credit of the observation has been generally accorded to J. B. Morin in 1635. Arago, for instance, says: “II est evident que c'est à Morin qu'il faut remonter pour trouver la première observation authentique d'une étoile vue en plein jour;” Zach and many other astronomical writers have held the same opinion. Morin's observations are found in his work, “Longitudinum Terrestrium necnon Cœlestium nova et hactenus optata Scientia,” first published, as it appears, in an extended form at Paris in 1638. At the end of March, 1635, he saw Arcturus half an hour after sunrise. This observation of Morin's appears to have been overlooked in France, since in May,. 1669, we find Picard expressing his surprise that he had been able to observe the meridian altitude of Regulus thirteen minutes before sunset; his observation is printed in Lemonnier's “Histoire Céleste”: “Le 3 mai (1669), hauteur méridienne de Regulus 54° 42′ 50″, cette hauteur méridienne fut prise en plein jour à 7h. 5m. du soir, environ 13m. avant le coucher du Soleil, ce qui ne s'étoit encore jamais fait.” On July 23 following he observed the meridian-altitude of Arcturus, while the sun was 17° above the horizon, and speaks of the observation as a remarkable one, concluding: “il est maintenant facile de trouver immédiatement les Ascensions droites des Etoiles fixes non seulement par les horlogès à pendule, mais aussi par l'observation du vertical du Soleil au même temps qu'on observera la hauteur méridienne d'une etoile fixe.”
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Our Astronomical Column . Nature 25, 421 (1882). https://doi.org/10.1038/025421a0
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DOI: https://doi.org/10.1038/025421a0