Moon to Meet the Seven Sisters of the Pleiades in a Stunning Occultation Event

Skywatchers in the western United States will have the chance to witness a rare celestial spectacle in the early morning hours of Sunday, September 22, 2024. During this event, the waning gibbous moon, illuminated at 75%, will pass directly in front of the Pleiades star cluster—also known as the Seven Sisters. This alignment, called an occultation, will allow observers to see the moon temporarily block some of the brightest stars in this famous cluster, creating a striking view as the stars disappear and reappear behind the moon's glowing disk.

The Pleiades: A Stellar Family with Deep Mythological Roots

The Pleiades star cluster, also referred to as Messier 45 (M45), is one of the most easily recognizable groups of stars in the night sky. Situated in the zodiacal constellation Taurus, the Pleiades are a tightly packed cluster of hot, young stars that have been visible to the naked eye for thousands of years. The cluster’s close grouping and its bright blue-white stars make it stand out against the darker regions of space, and it is especially prominent during the winter months in the northern hemisphere.

To the naked eye, the Pleiades look like a small cloud of light, but with binoculars or a telescope, observers can distinguish individual stars, often spotting six or seven of them. In mythology, the Pleiades are often referred to as the Seven Sisters, representing the daughters of Atlas and Pleione. The cluster’s brightest stars—Alcyone, Maia, Electra, Merope, and others—are named after these mythological sisters.

The Pleiades' closeness to Earth, at a distance of about 440 light-years, combined with its brilliance, has made it a central feature in the skywatching traditions of many cultures. It has long been a reference point for astronomy and mythology alike, symbolizing family and unity.

Understanding an Occultation: A Celestial Alignment

An occultation occurs when one celestial body passes directly in front of another, temporarily hiding it from view. In this case, the moon will pass in front of several of the Pleiades stars, causing them to disappear behind the moon’s illuminated surface and then reappear from behind its darkened limb. This occultation will be particularly striking because the moon will be in its waning gibbous phase, creating a dramatic contrast as the stars blink out of sight and then reemerge.

For those interested in observing the occultation, the event will be visible to the naked eye, but using binoculars or a telescope will offer a clearer and more detailed view. The stars will disappear behind the bright edge of the moon and then reappear from behind the shadowed side, providing an exciting visual experience. Even for casual observers, seeing the moon in close proximity to the Pleiades will be a rewarding experience.

Best Viewing Locations and Timing for The Event

The occultation of the Pleiades will be best viewed from the western United States, where the event will take place under dark skies. Those in the Pacific Time Zone will have the best opportunity to see the entire occultation, as it will occur before twilight, offering clear visibility of the moon and stars against the dark night sky. For observers in this region, the occultation will start and finish while the sky remains dark, providing optimal conditions for viewing.

In the Mountain Time Zone, the event will begin in darkness but will end as the sky begins to brighten during twilight. Viewers in this region should still have a good chance of observing most of the occultation, but the latter stages may be affected by the brightening sky.

For those in the Central and Eastern United States and Canada, the event will be more challenging to see. In these regions, the moon will begin to occult the Pleiades either during twilight or after sunrise, making it difficult to observe the stars against the brightening sky. For example, in Chicago, the star Electra will disappear around 5:01 a.m. CDT while the sky is still dark, but it will reappear during mid-twilight, when the sky is already beginning to brighten. In Denver, the star will disappear at 3:43 a.m. MDT and reappear at 4:13 a.m., both while the sky remains relatively dark.

The Importance of Celestial Occultations

Occultations like this offer valuable opportunities for both amateur and professional astronomers to observe the intricate interactions between celestial bodies. The alignment of the moon with the Pleiades provides a unique perspective on how objects in our sky move relative to one another. For experienced stargazers, this occultation presents a rare chance to watch the moon engage with one of the most famous star clusters, while for newcomers, it offers a dramatic introduction to celestial mechanics.

This occultation is part of a longer series of similar events involving the moon and the Pleiades, which will continue over the coming years. Each occultation offers slightly different viewing conditions and can be influenced by the moon’s phase and the positions of the Pleiades stars. Such events remind us of the dynamic nature of the night sky and offer exciting opportunities to engage with astronomy.

Looking Ahead: Future Occultations and Celestial Events

The September 22 occultation is only one of several opportunities in the coming years for skywatchers to see the moon interact with the Pleiades. As the moon continues its journey through the night sky, it will periodically pass in front of this star cluster, creating similar occultations. Each event provides a unique chance to observe the interactions between these two celestial objects under varying conditions.

For those interested in capturing the event on camera, astrophotography offers an exciting way to document the moon’s journey across the sky. Whether you use a telescope, binoculars, or even just a good camera, photographing the moon alongside the Pleiades can result in stunning images. Guides on how to photograph the moon and tips for using the best cameras and lenses for astrophotography can help ensure you capture the event in the best possible light.

For now, make sure to mark your calendars for September 22, 2024, and prepare for a rare and beautiful celestial event as the moon meets the Pleiades in a memorable occultation.