Beobachtung des Procyon als Doppelstern. Offprint from Mélanges mathématiques et astronomiques tirés du Bulletin de l Académie impériale des sciences de Saint-Pétersbourg (dated 27 March/8 April 1873). With two autograph letters by Struve.

STRUVE, Otto Wilhelm von

Publication Date: 1874

About this Item

First edition, extremely rare offprint, of Struve's 'discovery' of the faint companion to the star Procyon, which together form a binary system. This offprint is accompanied by two signed autograph letters from Struve to the Scottish amateur astronomer Robert Stirling Newall (1812-89), who at the time owned the largest refracting telescope in the world, asking Newall to confirm Struve's observations. In the first letter, dated 19 March 1873, Struve writes: "This evening with an extraordinary transparent sky and excellent images, I thought I could see a small companion of Procyon at a distance of somewhat more than 10". I would be most happy if this discovery could be independently confirmed by your magnificent telescope and for this reason I abstain from communicating to you in what direction that object was. Pray look out for Procyon and let me know if and where you see that small object. It was so distinctly seen and measured this evening that I hardly can believe it was an optical illusion." In the second, dated 28 April 1873, he continues: "I am sorry to say that what you have thought to be the newly discovered companion is a small star in 40" distance, repeatedly observed by me since 12 years and which does not participate in the proper motion of the principal star. The true companion, as I have seen it, is more than three times nearer to Procyon on the following side. With a tolerably good state of the atmosphere I have no doubt you will see it easily . . . " Neither Newall nor other contemporary astronomers were able to do so, however, and it was later shown that Struve's observations were illusory, probably caused by a defect in his telescope lenses. Eventually, Struve withdrew his claim to have discovered the companion of Procyon. Ironically, however, Struve was correct that Procyon is a binary system: the companion star was observed by the Lick Observatory in 1896. OCLC lists only one copy of the offprint (Hamburg). 8vo, pp. 21-28 (foxing). Original plain blue wrappers (creased vertically for posting). The two ALS's each two pages on a single sheet folded once. Seller Inventory # ABE-1633016747248

Bibliographic Details

Title: Beobachtung des Procyon als Doppelstern. ...

Publication Date: 1874

Binding: Soft cover

Condition: Very Good

Edition: 1st Edition