simple-astronomy-lib

A simple and free astronomy library for calculating moon phases.

A simple (and free) astronomy library for calculating moon phase, solar eclipses, etc. This is intended to be used as a library within other projects, thus the list of dependencies will remain as small as possible.

Initial code based on the book Practical Astronomy with your Calculator by Peter Duffett-Smith. If there are errors in the output it is due to my implementation and not because of that text.

• read here on archive.org
• buy here on Amazon

The next book I plan to purchase is Practical Astronomy with Your Calculator or Spreadsheet by the same author.

• read here on archive.org
• buy here on Amazon

NOTE: additional collaborators welcome

Current Functionality

Find dates for Moon Phases

• full moon
• new moon
• first quarter
• last quarter

Getting Started / Example

For a brief page on how to use this library, read the Getting Started page

Project Goals

• Minimize number of dependencies (useful for mobile device usage)
• Accuracy to within 5 minutes (currently +/-15 minutes)

New Features Under Consideration

• Sunrise / Sunset
• Rising and setting of other celestial objects
• Solar Eclipse - find date of next solar eclipse
• Lunar Eclipse - find date of next lunar eclipse
• Find location of sun or moon (right ascension, declination)

Schedule

• move the "Getting Started" example to GitHub DONE!
• Initial code commit before April 1, 2011 DONE!
• Decent documentation on usage before June 30, 2011 DONE!
• Github Actions CI builds 2026 DONE!
• Automated unit test coverage of more than 75% of code 2026 DONE!