java

Astronomy Engine examples in Java

The class file Main.java shows examples of how to use the Kotlin version of Astronomy Engine from a Java program.

The demo program is split into separate source files, one for each topic, as listed below. Each topic is chosen by a command line parameter. To build the demo program, run this command in Linux or Mac:

./gradlew jar

On Windows, use this command to build the demo program:

gradlew.bat jar

Then use the rundemo script (or rundemo.bat file on Windows) to run the demo program, to see usage text:

./rundemo

As an example, to run the MoonPhase demo, try this:

./rundemo moonphase

---

Constellation.java

This demo finds what constellation the Moon is in at a given time. It also shows how to do a binary search to find the moment in time when the Moon moves across the border between constellations.

JupiterMoons.java

Calculates the coordinates of Jupiter and its four major moons (Io, Europa, Ganymede, and Callisto) as seen from the Earth at a given date and time. This demo illustrates how to correct for the delay caused by the time it takes for light to reach the Earth from the Jupiter system.

LunarEclipse.java

Searches for the first 10 lunar eclipses (partial or total) that occur after the specified time. Penumbral lunar eclipses are ignored, as these are difficult to observe in practice.

MoonPhase.java

This example shows how to determine the Moon's current phase, and how to predict when the next 10 quarter phases will occur.

Positions.java

Given an observer's geographic latitude and longitude, and an optional date and time, this demo displays the equatorial and horizontal coordinates of the Sun, Moon, and planets.

RiseSetCulm.java

Calculates rise, set, and culmination times of the Sun and Moon. Culmination is when a body reaches the highest point in an observer's sky as it crosses the meridian.

Seasons.java

Calculates the equinoxes and solstices for a given calendar year.