## AstroAlgos.com is based on the book 'Astronomical Algorithms' by Jean Meeus.

This website uses Meeus equations to calculate the exact positions of planets. In fact, calculations based on the simple Newtonian laws, for example, where the Earth is only subject to the gravitational attraction of the Sun, are not precise because they do not take into account the gravitational force of other planets. The calculation of the position of stars uses all the methods used in "Astronomical Algorithms".

## Astronomical Algorithms

"Astronomical Algorithms" is a reference guide written by Belgian astronomer and mathematician Jean Meeus, first published in 1979. The book is widely considered a classic in the field of celestial mechanics, and it remains a popular reference for astronomers and celestial navigators.

The book covers a wide range of topics related to astronomy and celestial mechanics, including the positions and motions of the sun, moon, planets, and stars. It provides detailed explanations of various algorithms and formulas used in astronomy, along with tables of data and other useful information.

### Mathematics and Equations Covered

The book is primarily focused on providing algorithms and equations for calculating the positions and motions of celestial objects. These calculations are essential for a wide range of applications in astronomy and celestial navigation.

**Kepler's laws:**These are three laws of planetary motion developed by Johannes Kepler in the early 17th century. They describe the motion of planets around the sun in terms of elliptical orbits and the conservation of angular momentum. Kepler's laws are essential for calculating the positions and motions of planets, and they are covered in detail in "Astronomical Algorithms."**Spherical trigonometry:**This is a branch of trigonometry that deals with triangles on the surface of a sphere. Spherical trigonometry is essential for calculating the positions of celestial objects in terms of latitude and longitude coordinates. The book covers a wide range of formulas and equations for solving spherical triangles, including the law of cosines and the law of sines.**Coordinate systems:**"Astronomical Algorithms" covers a variety of different coordinate systems used in astronomy, including equatorial coordinates, ecliptic coordinates, and horizontal coordinates. The book provides formulas and algorithms for converting between these different coordinate systems, which is essential for calculating the positions of celestial objects in different parts of the sky.**Lunar phases and eclipses:**The book provides detailed algorithms for The book provides detailed algorithms for calculating the phases of the moon and predicting lunar eclipses. These calculations are based on the positions of the sun, moon, and earth relative to each other, and they require complex equations and algorithms for accurate predictions.**Planetary positions:**"Astronomical Algorithms" provides algorithms and equations for calculating the positions of the planets in the solar system. These calculations are based on the planets' orbits around the sun and require a variety of mathematical techniques, including numerical integration and approximation.

Overall, "Astronomical Algorithms" is a comprehensive reference guide that covers a wide range of mathematical concepts and techniques related to astronomy and celestial navigation. The book is essential for anyone working in these fields and provides a valuable resource for understanding the underlying mathematics and equations involved in these calculations.

## Jean Meeus - Astronomer and Mathematician

Jean Meeus was a renowned Belgian astronomer and mathematician, known for his contributions to the field of celestial mechanics and astronomical calculations. He was born on February 12, 1928, in Belgium, and developed an early interest in astronomy and mathematics, which led him to pursue a career in these fields.

#### Education and Career

Meeus completed his studies in mathematics at the University of Louvain, Belgium, in 1953. He later joined the Royal Observatory of Belgium in Brussels, where he worked for several years as an astronomer and researcher. During this time, he developed a deep interest in celestial mechanics and began working on various mathematical models and algorithms for calculating the positions of celestial objects.

#### Contributions to Astronomy

In the 1970s, Meeus published his first book, "Astronomical Algorithms," which quickly became a popular reference guide for astronomers and celestial navigators. The book contained detailed explanations of various algorithms and formulas used in astronomy, such as those for calculating the positions of planets and stars. It also included tables of data and other useful information, making it an invaluable tool for anyone working in the field of astronomy.

Meeus continued to publish books and research papers throughout his career, focusing on topics such as eclipses, lunar phenomena, and the motions of the planets. In 1982, he published "The Canon of Solar Eclipses," a comprehensive guide to all solar eclipses visible from Earth between 2000 BCE and 3000 CE. The book was praised for its accuracy and attention to detail, and it became a standard reference for astronomers and eclipse enthusiasts.

In addition to his research, Meeus was also a skilled observer of the night sky. He spent many hours observing celestial phenomena and was known for his ability to accurately predict the timing and location of various events, such as eclipses and conjunctions.

#### Awards and Honors

Meeus was a member of several scientific organizations, including the Royal Astronomical Society, the International Astronomical Union, and the Belgian Astronomical Society. He was also a recipient of numerous awards and honors, including the Prix Jules Baillaud from the French Academy of Sciences in 1983 and the James Craig Watson Medal from the National Academy of Sciences in 1992.

Meeus passed away on May 21, 2017, at the age of 89. His contributions to the field of astronomy and celestial mechanics continue to be remembered and celebrated by astronomers and researchers around the world.