Observe the moon over a few nights and you’ll soon notice a couple of things about it. It doesn’t rise and set at the same time of day (as does the Sun) and the bright portion of its disk changes slightly from night to night; sometimes the bright fraction decreases and sometimes it increases.

Other observations you might make are that the moon looks bigger on the horizon that when overhead; you can see large dark and bright areas on its surface and smaller features as well; you can sometimes see it during the day and occasionally, it turns a coppery brown color.

There’s more to the moon than meets the eye!

Click any of the images below to see a full-size image.

Moon Phases This Month
Diagram created with LunarPhase Pro

Lunar Libration Diagram

Max and Min Lunar Librations For The Month

The plot with big yellow dots and little orange dots between them shows the moon’s topocentric libration for the month [topocentric means as seen from your location].

The plot tends to oscillate between daily positions.

This plot is for Dublin, Ireland.

The plot that’s made up of light blue dots connected by darker blue lines shows the moon’s Geocentric libration (i.e. as it would be seen from the center of the Earth).

This is a much smoother plot since it doesn’t account for your changing position relative to the moon as each day progresses.

LunarPhase Pro will generate diagrams and data for your location.

Below are times for viewing Crescent Moons in UT for Dublin, Ireland.

Crescent data is specific for your location but adding your timezone offset from GMT to the Sunset and Moonset times will give you an idea of when the Moon is visible locally.

The amount of time you have to see a crescent and what percentage of the Moon is illuminated will be somewhat different for where you live.

LunarPhase Pro will calculate all this information specifically for your location.

The data in the screenshot below was generated by the software.

Crescent Moon Phases This Month