Ernest LAUGIER, Astronomer. (1812 - 1872) - 1 autograph lett - Lot 472

Lot 472
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Estimation :
400 - 500 EUR
Ernest LAUGIER, Astronomer. (1812 - 1872) - 1 autograph lett - Lot 472
Ernest LAUGIER, Astronomer. (1812 - 1872) - 1 autograph letter signed, 1 autograph Manuscript and 1 Lithograph : Autograph Manuscript by LAUGIER of an article "Note on the proper motion of SIRIUS in polar distance" (SIRIUS The brightest Star in the Sky discovered in 1844 by Bessel; confirmed in 1862) - 1p 1/2 in-4°, with erasures and corrections, with additions of indications, in another hand, for publication. Laugier explains that there has been a tendency up to now to assume that "when the mean positions of the stars are carried from one epoch to another, the proper motions of the stars are uniform". He is anxious to prove that a small number of stars are exceptions, and SIRIUS is the most remarkable of these. He makes a very technical demonstration, giving the mathematical formula which makes it possible to calculate the polar distance at the various periods (from 1690 to 1852) + Letter A.S. of the Astronomer LAUGIER, 1p in-8° - to the Editor to whom this manuscript is intended: "I have the honor to address to you the small note on the proper movement of SIRIUS, which you agreed to ask me... I have done my best to shorten it without losing its intelligibility. I hope I have not omitted anything essential. Forgive me for the bad writing. I didn't have time to clean it up..." + Litho (39 x 28 cm), from a photograph by Pierson. Impr. Lemercier et Cie Paris, 1869.
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