He is best known for studying double stars and initiating a triangulation survey later named Struve Geodetic Arc in his honor.

To avoid military service during the French occupation of Holstein, his family moved to the Russian Empire,[3][4][5] equipped with Danish passports.

[3][4][5] Struve was occupied with research on double stars and geodesy in Dorpat until 1839, when he founded and became director of the new Pulkovo Observatory near St Petersburg.

While at Dorpat he obtained in 1824 a refracting telescope with an aperture of 23 cm (about 9 inches) made by Joseph von Fraunhofer, said to be a masterpiece of optical and mechanical quality.

Thus Struve made micrometric measurements of 2714 double stars from 1824 to 1837 and published these in his work Stellarum duplicium et multiplicium mensurae micrometricae.

[5] In an 1847 work, Etudes d'Astronomie Stellaire: Sur la voie lactee et sur la distance des etoiles fixes, Struve was one of the first astronomers to identify the effects of interstellar extinction (though he provided no mechanism to explain the effect).

He initiated the Struve Geodetic Arc, a chain of survey triangulations stretching from Hammerfest in Norway to the Black Sea, through ten countries and over 2,820 km, to establish the exact size and shape of the earth.

The most well-known was Karl von Struve (1835–1907), who served successively as Russian ambassador to Japan, the United States, and the Netherlands.

[3][5] Bernhard's son Pyotr Struve (1870–1944) is probably the best known member of the family in Russia proper (his other descendants mainly resided in Estonia and Latvia, and subsequently in Germany).