Celestial Calculations

Celestial Calculations

A Gentle Introduction to Computational Astronomy

By J. L. Lawrence

How to predict and calculate the positions of stars, planets, the sun, the moon, and satellites using a personal computer and high school mathematics.





How to predict and calculate the positions of stars, planets, the sun, the moon, and satellites using a personal computer and high school mathematics.

Our knowledge of the universe is expanding rapidly, as space probes launched decades ago begin to send information back to earth. There has never been a better time to learn about how planets, stars, and satellites move through the heavens. This book is for amateur astronomers who want to move beyond pictures of constellations in star guides and solve the mysteries of a starry night. It is a book for readers who have wondered, for example, where Saturn will appear in the night sky, when the sun will rise and set, or how long the space station will be over their location. In Celestial Calculations, J. L. Lawrence shows readers how to find the answers to these and other astronomy questions with only a personal computer and high school math. Using an easy-to-follow step-by-step approach, Lawrence explains what calculations are required, why they are needed, and how they all fit together.

Lawrence begins with basic principles: unit of measure conversions, time conversions, and coordinate systems. He combines these concepts into a computer program that can calculate the location of a star, and uses the same methods for predicting the locations of the sun, moon, and planets. He then shows how to use these methods for locating the many satellites we have sent into orbit. Finally, he describes a variety of resources and tools available to the amateur astronomer, including star charts and astronomical tables. Diagrams illustrate the major concepts, and computer programs that implement the algorithms are included. Photographs of actual celestial objects accompany the text, and interesting astronomical facts are interspersed throughout.

Source code (in Python 3, JAVA, and Visual Basic) and executables for all the programs and examples presented in the book are available for download at https://CelestialCalculations.github.io.


$39.95 T ISBN: 9780262536639 392 pp. | 6 in x 9 in 80 b&w illus.


  • A recommended read for anyone looking to understand how we can predict where celestial objects will appear in the sky

    BBC Sky at Night

  • This book is quite an achievement.

    European Mathematical Society


  • In this age with the Gaia spacecraft bringing attention to the importance of astrometry, here is a book for do-it-yourselfers who want to work with star positions, time-system and calendar conversions, and other mathematical calculations of astronomical interest.  The book has the detailed quality you'd expect with its MIT imprimatur.

    Jay Pasachoff

    Field Memorial Professor of Astronomy, Williams College

    author of the Peterson Field Guide to the Stars and Planets, 4th ed.; coauthor of The Cosmos: Astronomy in the New Millennium, 5th ed.

  • This book is a great resource for anyone wishing to explore the applied mathematics of solar system celestial mechanics. The step-by-step guide to calculating orbits, sunrise-sunset time, and lunar and solar position forecasting is so good that even a professional astronomer will find it an invaluable reference book.

    Dr. Sten Odenwald

    Director, Citizen Science NASA Space Science Education Consortium

  • In today's new era of cubesats and extrasolar asteroids, it's fun to explore the "What ifs... ?" of where these things can go. With Jackie Lawrence's new Celestial Calculations book, it's now possible for anyone with high school trig to do back-of-the-envelope calculations exploring the future of Elon Musk's Starman, or possible configurations of alien solar systems. This is my new quick reference for calculating 'Where will it go?' and 'Where can I see it?'

    Pamela Gay

    Senior Scientist, Planetary Science Institute