Apps in this category may contain mild or occasional cartoon, fantasy or real-life violence, as well as occasional or mild adult, sexually suggestive or horrifying content and may not be suitable for children under 9 years of age.

12+

Apps in this category may contain occasional mild indecent language, frequent or intense cartoon or real-life violence, minor or occasional adult or sexually suggestive material, and simulated gambling, and may be for children under 12 years of age.

17+

You must be at least 17 years old to access this App.

Apps in this category may contain frequent and intense offensive language; Frequent and intense cartoon, fantasy or realistic violence: frequent and intense adult, scary and sexually suggestive subjects: as well as sexual content, nudity, tobacco, alcohol and drugs, may not be suitable for children under 17 years of age.

Moon phases assist Screenshots

iPad

iPhone

About Moon phases assist

This app allows you to visually learn about the different phases of the moon depending on the positions of the moon, the Earth, and the Sun.

The app has undergone a major overhaul to improve its features!

Why does the moon have different phases?
Why does the height of the Sun change depending on the season?
These diagrams provide easy answers to these questions!

You can intuitively grasp the positions of the Sun, the Earth, and the moon through overhead and celestial sphere diagrams!

What are the positions of the Sun and the moon during a full moon?
Where is the Sun when the waning crescent transits the meridian?

You can answer these questions by turning the dial and checking their positions!

※The size and distance of celestial objects are not drawn to scale but exaggerated for easier understanding.
※For easier understanding, the Earth's orbit is made circular instead of elliptic while the inclination of the moon's orbit has been omitted.

What's New in the Latest Version 3.3.0

Last updated on Jan 19, 2024

Old Versions

Support iOS 17.
Improved stability and performance.
Fixed some bugs.

Version History

3.3.0

Jan 19, 2024

Support iOS 17.
Improved stability and performance.
Fixed some bugs.

3.2.0

Dec 14, 2022

Changed to look at the moon facing north. (When the observer's position is set to the southern hemisphere.)
Added rotate sun direction by dragging. (In the second viewpoint.)
Fixed some bugs.

3.1.0

Dec 8, 2022

Added sound effects.
Fixed some bugs.

3.0.0

Dec 3, 2022

Changed the user interface.
Optimized resources.
Optimized processing.
Fixed some bugs.

2.3.0

Aug 12, 2020

Can be 2 screens.

2.2.0

Aug 6, 2020

The latitude and longitude can now be selected from the setting screen.