## What is Hipparchus best known for?

Hipparchus of Nicaea (/hɪˈpɑːrkəs/; Greek: Ἵππαρχος, Hipparkhos; c. 120 BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of precession of the equinoxes.

### Who is Ptolemy and his contribution?

Ptolemy made contributions to astronomy, mathematics, geography, musical theory, and optics. He compiled a star catalog and the earliest surviving table of a trigonometric function and established mathematically that an object and its mirror image must make equal angles to a mirror.

#### Who is known as the father of trigonometry?

The first known table of chords was produced by the Greek mathematician Hipparchus in about 140 BC. Although these tables have not survived, it is claimed that twelve books of tables of chords were written by Hipparchus. This makes Hipparchus the founder of trigonometry.

What did Eratosthenes do?

Eratosthenes, in full Eratosthenes of Cyrene, (born c. 276 bce, Cyrene, Libya—died c. 194 bce, Alexandria, Egypt), Greek scientific writer, astronomer, and poet, who made the first measurement of the size of Earth for which any details are known.

How did Hipparchus invent trigonometry?

Hipparchus produced a table of chords, an early example of a trigonometric table. He did this by using the supplementary angle theorem, half angle formulas, and linear interpolation. Hipparchus calculated the length of the year to within 6.5 minutes and discovered the precession of the equinoxes.

## How did Hipparchus use parallax?

Hipparchus concentrated on point C at the edge of the Moon, which during totality, when viewed from the Hellespont (point A), just overlapped point D on the edge of the Sun. Note that in astronomy this angle is called the parallax of the edge of the Moon as viewed from the above two locations.

### Who was Ptolemy to Alexander the Great?

367 BC – January 282 BC) was a Greek general, historian and companion of Alexander the Great of the Kingdom of Macedon in northern Greece who became ruler of Egypt, part of Alexander’s former empire. Ptolemy was pharaoh of Ptolemaic Egypt from 305/304 BC to his death.

#### What is the contribution of Ptolemy to the universe model?

The most important feature of Ptolemy’s model was that the Earth was at the centre – the geocentric model of the universe. Ptolemy’s tables were so effective at predicting positions in the night sky that they were used to prepare astronomical and astrological charts for over 1,500 years.

Why is Hipparchus called father of trigonometry?

He is considered to be “the father of trigonometry”. He created the first trigonometric table and solved several problems of spherical trigonometry by representing the corresponding values of arc and chord for a series of angles such as 0°, 30°, 45°, 60° and 90°, etc.

When was Hipparchus born?

190 BC
Hipparchus/Date of birth

Hipparchus was born in Nicaea, Bithynia (now Iznik, Turkey), circa 190 B.C. He spent much of his time in Rhodes, Greece.

## What Hipparchus contributed to astronomy?

Hipparchus, (b. Nicaea, Bithynia–d. after 127 BC, Rhodes?), Greek astronomer and mathematician who discovered the precession of the equinoxes, calculated the length of the year to within 6 1/2 minutes, compiled the first known star catalog, and made an early formulation of trigonometry.

### What did Hipparchus contribute to the field of trigonometry?

He has contributed to the field of trigonometry and astronomy. He has derived many trigonometry formulas and equations. How did Hipparchus discover trigonometry? He made the table of the chords of angles available to scholars.

#### What are the devices discovered by Hipparchus?

The devices like gnomon, the armillary sphere, the astrolabe, and many more were been discovered by Hipparchus. What is the contribution of Hipparchus? He has contributed to the field of trigonometry and astronomy. He has derived many trigonometry formulas and equations.

What did Hipparchus of Nicaea contribute to astronomy?

Hipparchus of Nicaea (/hɪˈpɑːrkəs/; Greek: Ἵππαρχος, Hipparkhos; c. 190 – c. 120 BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry but is most famous for his incidental discovery of precession of the equinoxes.

Who is Hipparchus of Bithynia?

So little of Hipparchus’s life has been recorded, but he is considered the very founder of trigonometry. Reasonably enough Hipparchus is often referred to as Hipparchus of Nicaea or Hipparchus of Bithynia and he is listed among the famous men of Bithynia by Strabo, the Greek geographer and historian who lived from about 64 BC to about 24 AD.