Hipparchus

Definition

Hipparchus was an ancient Greek astronomer and mathematician who is often considered the founder of trigonometry. He made significant contributions to the understanding of celestial bodies and their movements.

5 Must Know Facts For Your Next Test

1. Hipparchus compiled the first comprehensive star catalog around 129 BCE.
2. He discovered the precession of the equinoxes, noting that the positions of stars change over time.
3. Hipparchus developed a method for predicting solar eclipses using his observations.
4. He introduced a scale for measuring the brightness of stars, which laid the groundwork for modern magnitude systems.
5. Hipparchus's work influenced later astronomers such as Ptolemy and helped shape early astronomy.

Review Questions

• What major astronomical discovery is Hipparchus credited with regarding the movement of stars?
• How did Hipparchus contribute to our understanding of star brightness?
• Which later astronomer was notably influenced by Hipparchus's work?

Related terms

Precession:

The slow movement of the axis of a spinning body around another axis due to external forces, such as gravity.

Magnitude Scale:

A system used to measure and compare the brightness of celestial objects.

Star Catalog: A comprehensive list or database detailing positions and characteristics of stars in the night sky.