full moon
An image of one full side of the moon. NASA

This year has been packed full of great shows in the sky thanks to nature in the form of a total solar eclipse, meteor showers and full moons. On Sunday night, another one of those remarkable events began. The moon is going through a period of occultation, called a lunar occultation. This essentially means that the moon is passing in front of other notable objects in the sky, an occultation is when an object that appears larger passes in front of an object that appears smaller, according to NASA.

Sunday evening and into Monday morning the moon passed in front of Venus and the star Regulus. Regulus is one of the brightest stars in the night sky, making it fairly noticeable when it’s not visible. Later in the day Monday, the moon will occult Mars and Mercury. During 2017 alone, the moon will occult Mars and Neptune six times.

Occultations are important because they give astronomers new insights to planets and stars. The occultation offers a different view of the celestial body that can reveal new features about it like size, shape and atmospheric properties. It was actually during an occultation in 1977 that the rings around Uranus were discovered.

Earlier this year researchers were able to learn about the distant Kuiper Belt Object called 2014 MU69 during an occultation. The object will be studied by the New Horizons spacecraft that is set to fly by it on Jan. 1, 2019. Researchers used the information gained from the occultation to piece together the shape and size of the KBO prior to the flyby.

In North America the current lunar occultation won’t look like much. The three planets and Regulus will align in a slight diagonal but it will occur partially during the day so without a telescope the moon, planets and the star will all be difficult to see. The best viewing spots will actually be in Australia, New Zealand and Indonesia. A small telescope would be sufficient for viewing the event in these areas. Those in North America will be able to see the objects lined up, but they won’t be able to see the moon actually cover up any of the planets or the star.

The International Occultation Timing Association tracks the occultations of stars and planets around the world and provides basic information about viewing the events as well. Visitors to the site can select a viewing location to see when the next visible occultation in their area will occur. The occultation of the three planets as well as the star in less than one day’s time is a fairly rare event and won’t occur again until 2036.