Alexander Filippovich Postels (Russian: Александр Филиппович Постельс; 24 August 1801 Dorpat – 26 June 1871 Vyborg), was a Baltic German of Russian citizenship naturalist, mineralogist and artist.
Postels studied at St.Petersburg Imperial University and in 1826 lectured there on inorganic chemistry.
In the 1820s political relations between Russia and the United States were troubled by the extent of Russian territory in North America. Russia intended to enforce its claims by sending two warships to the disputed areas. When the two countries agreed on 54°40′N as the southern limit of Russian claims, Czar Nicolas I changed their orders in 1826 to an extended three-year survey of the Russian-American and Asian coasts.
Otto von Kotzebue had returned on 10 July 1826 from his voyage of discovery aboard Predpriyatiye. On 16 August 1826, Captain Lieutenant Fedor Petrovich Litke, sailed on board the Russian vessel Senyavin, accompanied by the Möller under Captain Lieutenant M. N. Staniukovich. Postels sailed with Litke as a naturalist/artist and had the distinction of being the first St. Petersburg University graduate to join such a large-scale expedition. On board were also the naturalist Karl Heinrich Mertens (1796-1830), who died in Kronstadt shortly after his return from Iceland and another trip on the Senyavin, and the ornithologist Baron von Kittlitz.
Their orders were to
"reconnoitre and describe the coasts of Kamchatka, the land of the Chuchkis and the Koriaks (the coasts of which have not yet been described by anyone, and which are unknown except by the voyage of Captain Bering); the coasts of the Okhotsk Sea, and the Shantar Islands, which although they are known to us, have not been sufficiently described."