Agrippa (; ) was a

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

. The only thing that is known about him regards an astronomical observation that he made in 92 AD.

Ptolemy Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...

writes that in the twelfth year of the reign of

Domitian Domitian ( ; ; 24 October 51 – 18 September 96) was Roman emperor from 81 to 96. The son of Vespasian and the younger brother of Titus, his two predecessors on the throne, he was the last member of the Flavian dynasty. Described as "a r ...

, on the seventh day of the

Bithynia Bithynia (; ) was an ancient region, kingdom and Roman province in the northwest of Asia Minor (present-day Turkey), adjoining the Sea of Marmara, the Bosporus, and the Black Sea. It bordered Mysia to the southwest, Paphlagonia to the northeast a ...

n month ''Metrous'', Agrippa observed the

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks f ...

of a part of the

Pleiades The Pleiades (), also known as Seven Sisters and Messier 45 (M45), is an Asterism (astronomy), asterism of an open cluster, open star cluster containing young Stellar classification#Class B, B-type stars in the northwest of the constellation Tau ...

by the southernmost part of the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. The purpose of Agrippa's observation was probably to check the

precession Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In o ...

of the

equinox A solar equinox is a moment in time when the Sun appears directly above the equator, rather than to its north or south. On the day of the equinox, the Sun appears to rise directly east and set directly west. This occurs twice each year, arou ...

es, which was discovered by

Hipparchus Hipparchus (; , ; BC) was a Ancient Greek astronomy, Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equinoxes. Hippar ...

. The lunar crater

Agrippa Agrippa may refer to: People Antiquity * Agrippa (mythology), semi-mythological king of Alba Longa * Agrippa (astronomer), Greek astronomer from the late 1st century * Agrippa the Skeptic, Skeptic philosopher at the end of the 1st century * Ag ...

is named after him.

References

External links

Agrippa
Ancient Greek astronomers 1st-century Greek people 1st-century births 1st-century deaths 1st-century astronomers {{Greece-scientist-stub