Here’s how to see the Lunar X and V at 1st-quarter moon

View at EarthSky Community Photos. | Kannan A in Singapore wrote on April 19, 2021: “Upon a close look at the moon tonight, I realized that the Lunar X and Lunar V were clearly visible. These are transient lunar features visible on the lunar surface for about 4 hours once a month. They are most striking when they are visible on the shadow side of the terminator. But they will remain visible against the lunar surface even after the terminator has moved because they are brighter than the surrounding area.” Thank you, Kannan!

2025 EarthSky lunar calendar is available now. A unique and beautiful poster-sized calendar with phases of the moon for every night of the year. Get yours today!

Lunar X and Lunar V

Have you heard of Lunar X and Lunar V? They are famous optical features on the moon, visible through telescopes. So, when the moon’s terminator – or line between light and dark on the moon – is located in just the right place, you can see a letter X and a letter V on the moon’s surface. Are they a sign of an alien visitation? No. Rather, Lunar X is a great example of how lighting and topography can combine on a planet or moon to produce a pattern that seems familiar to the human eye.

In reality, the illusion of Lunar X is created by sunlight falling on the rims/ridges between the craters La Caille, Bianchini and Purbach. The V is caused by light illuminating crater Ukert, along with several smaller craters.

View at EarthSky Community Photos. | Radu Anghel captured this image from Bacau, Romania, on April 27, 2023. Radu wrote: “X and V from tonight’s moon.” Thank you, Radu! Learn how to see Lunar X and V below.

When are they visible?

Basically, people see Lunar X and Lunar V at each cycle of the moon, but only for a short time. In fact, they’re observable for about four hours around the 1st quarter moon phase.

View at EarthSky Community Photos. | Matthew Chin from Hong Kong, China, shared this image of the moon, where Lunar X and Lunar V are visible, on January 18, 2024. Thank you, Matthew!

Bottom line: Lunar X and Lunar V are optical features on the moon. They are visible through a telescope for several hours around the time of the 1st quarter moon.

The post Here’s how to see the Lunar X and V at 1st-quarter moon first appeared on EarthSky.

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View at EarthSky Community Photos. | Kannan A in Singapore wrote on April 19, 2021: “Upon a close look at the moon tonight, I realized that the Lunar X and Lunar V were clearly visible. These are transient lunar features visible on the lunar surface for about 4 hours once a month. They are most striking when they are visible on the shadow side of the terminator. But they will remain visible against the lunar surface even after the terminator has moved because they are brighter than the surrounding area.” Thank you, Kannan!

2025 EarthSky lunar calendar is available now. A unique and beautiful poster-sized calendar with phases of the moon for every night of the year. Get yours today!

Lunar X and Lunar V

Have you heard of Lunar X and Lunar V? They are famous optical features on the moon, visible through telescopes. So, when the moon’s terminator – or line between light and dark on the moon – is located in just the right place, you can see a letter X and a letter V on the moon’s surface. Are they a sign of an alien visitation? No. Rather, Lunar X is a great example of how lighting and topography can combine on a planet or moon to produce a pattern that seems familiar to the human eye.

In reality, the illusion of Lunar X is created by sunlight falling on the rims/ridges between the craters La Caille, Bianchini and Purbach. The V is caused by light illuminating crater Ukert, along with several smaller craters.

View at EarthSky Community Photos. | Radu Anghel captured this image from Bacau, Romania, on April 27, 2023. Radu wrote: “X and V from tonight’s moon.” Thank you, Radu! Learn how to see Lunar X and V below.

When are they visible?

Basically, people see Lunar X and Lunar V at each cycle of the moon, but only for a short time. In fact, they’re observable for about four hours around the 1st quarter moon phase.

View at EarthSky Community Photos. | Matthew Chin from Hong Kong, China, shared this image of the moon, where Lunar X and Lunar V are visible, on January 18, 2024. Thank you, Matthew!

Bottom line: Lunar X and Lunar V are optical features on the moon. They are visible through a telescope for several hours around the time of the 1st quarter moon.

The post Here’s how to see the Lunar X and V at 1st-quarter moon first appeared on EarthSky.

from EarthSky https://ift.tt/Vf6bCgl