Berlin Observatory in the context of Prussian Academy of Sciences

Johann Gottfried Galle (9 June 1812 – 10 July 1910) was a German astronomer from Radis, Germany, at the Berlin Observatory who, on 23 September 1846, with the assistance of student Heinrich Louis d'Arrest, was the first person to view and identify the planet Neptune. Urbain Le Verrier had predicted the existence and position of Neptune, and sent the coordinates to Galle, asking him to verify. Galle found Neptune in the same night he received Le Verrier's letter, within 1° of the predicted position. The discovery of Neptune is widely regarded as a dramatic validation of celestial mechanics, and is one of the most remarkable moments of 19th-century science.

433 Eros is a stony asteroid of the Amor group, and the first discovered, and second-largest near-Earth object. It has an elongated shape and a volume-equivalent diameter of approximately 16.8 kilometers (10.4 miles). Visited by the NEAR Shoemaker space probe in 1998, it became the first asteroid ever studied from its own orbit.

The asteroid was discovered by German astronomer C. G. Witt at the Berlin Observatory on 13 August 1898 in an eccentric orbit between Mars and Earth. It was later named after Eros, a god from Greek mythology, the son of Aphrodite. He is identified with the planet Venus.

The planet Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observations confirming the existence of a major planet were made on the night of September 23–24, autumnal equinox of 1846, at the Berlin Observatory, by astronomer Johann Gottfried Galle (assisted by Heinrich Louis d'Arrest), working from Le Verrier's calculations. It was a sensational moment of 19th-century science, and dramatic confirmation of Newtonian gravitational theory. In François Arago's apt phrase, Le Verrier had discovered a planet "with the point of his pen".

In retrospect, after it was discovered, it turned out it had been observed many times before but not recognized, and there were others who made calculations about its location which did not lead to its observation. By 1846, the planet Uranus had completed nearly one full orbit since its discovery by William Herschel in 1781, and astronomers had detected a series of irregularities in its path that could not be entirely explained by Newton's law of universal gravitation. These irregularities could, however, be resolved if the gravity of a farther, unknown planet were disturbing its path around the Sun.