Accurately shows the current phase of the moon generated from a 3-D model of the earth-moon-sun geometry. Calculations are based on detailed equations that correctly take into account orbital characteristics such as inclination, distance, obliquity, nutation, libration, AND [optionally] the device's location on the surface of the Earth. Also generates relevant ephemeris data viewable on separate detail pages. Does not require a network connection; all calculations are performed locally within the app.

Estimates the traditional Hawaiian lunar calendar day name based on calculated predictions for when a sharp-eyed person under perfect conditions should be able to realistically see the first new lunar crescent at sunset after conjunction on Oahu. The traditional Hawaiian day ends at sunset, not midnight.

* Allows two-finger pinch-zoom gesture.

* Animate the phases of the moon over time by selecting "Animate" from the action menu; tap the animation to stop. Double-tap to reset back to current time, rotation, and zoom. The information icon in the lower-right corner brings up the action menu with multiple options.

* Details page displays several moon ephemeris calculations for the given date and time. Items can be reordered and/or deleted from the list to prioritize which data items are displayed. Long-press on a value to copy to clipboard.

* Motion sensors [if enabled] automatically rotate the moon image on the Phase tab to keep it in sync with what one might see in the sky. Enable Location Services for this feature to work. If Location Services are turned off, use the two-finger rotate gesture to manually rotate the moon image.

* Lists upcoming phases with their dates and times on the Upcoming tab, and optionally displays alert notifications when they are about to occur. Identifies full moon at perigee as a "super moon."

* Shows the phases of the moon for a full calendar year on the Calendar tab - swipe forward and backward to see other years.

* Today widget quickly shows the current phase of the moon and the traditional Hawaiian day name on the lock screen or when the app's icon is Force Touched. If location information is available, will also show the parallactic angle, whether the moon is visible above the horizon, and next rise and set times.

Two iOS permissions need to be granted for the app to utilize its full feature set. Location Services is needed to know when the moon rises and sets, and its orientation/rotation in the sky as seen from the device location. The app does not track the user's location or send that location off the device. It uses a three-kilometer location radius that updates whenever the device travels more than 10,000 kilometers from the last known position.

Notification permission is needed to display local alerts when phase milestones are about to occur (full moon, new moon, first and last quarters). The alerts are locally generated and do not come from any external service.

We will never show ads within this app!

What’s New

Version 3.0

Support iOS 13 and dark mode. Switch rendering from the deprecated OpenGL and custom shaders to SceneKit/Metal. Provide crater/mountain relief at the terminator. Remove detail page sections, allow for the detail item rows to be reordered, and any uninteresting items deleted. Provide icon for apogee/perigee rather than "A/P". New information listed on the Today widget. Long-press on detail item values brings up menu to copy to the clipboard. Fixed bug with upcoming phase milestones when approaching the next milestone.

Removed the planets and stars rendering. Will maybe add it back later if folks actually want it.

Ratings and Reviews

5.0 out of 5
2 Ratings

2 Ratings

Dumble-window ,

Price was right

Not a ton of features and I will only be using the “Upcoming” tab. But it was only 99 cents and I don’t see any ads, so here’s 5 stars!

Developer Response ,

Cool, mahalo! And there NEVER will be any ads in this app.
Any features in particular you’re looking for?

MJ Logan ,

Curious mom

Informational and interesting with info easy to understand.


Ronald Logan
15 MB

Requires iOS 12.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like