Limited time observation! Tomorrow night, the moon X will appear

On February 5, the eighth day of the first lunar month, the sky will welcome a waxing moon. If you look up at the moon, you will find a light and shadow similar to the letter "X" appearing on the surface of the moon. This is also the first "lunar X" this year. Interested astronomy enthusiasts can take a look at it!

What is "Lunar X"?

"Lunar X" is a unique light and shadow phenomenon on the lunar surface. This special light and shadow effect occurs when the edges of three craters on the lunar surface - Lacaille, Purbach and Bianchinus - are illuminated by sunlight at an angle close to the lunar surface. Finding "Lunar X" is a good opportunity to understand and observe the lunar landforms.

Image credit: Tokyo Ogikubo Astronomical Observatory

"Lunar X" was first discovered and reported by Canadian observers in 2004. Since then, this phenomenon has attracted the attention of many astronomy enthusiasts.

From an astronomical perspective, whenever the morning line in the lunar terminator is located near 2 degrees east longitude of the moon, "Lunar X" will appear . The appearance of the waxing moon phase corresponds to the morning line in the terminator reaching near the zero degree of lunar longitude, so the appearance time of "Lunar X" and the waxing moon phase are very close each time. According to Song Yuanyuan, director of the Tianjin Astronomical Society and astronomy popularization expert of Tianjin Science and Technology Museum, since the appearance time of lunar X is very short, lasting only about 1 hour, it is not visible every waxing moon, and the observation opportunity is very rare. Considering the time of the waxing moon and the position of the moon, the Chinese public has 6 opportunities to see them this year, namely February 5, April 5, June 3, August 1, September 29 and November 27 .

The moon is the brightest object in the night sky and can be seen even during the day as long as the weather is fine. Lunar Xs usually appear near the moon's twilight zone, which is the boundary between light and dark.

According to reports, the time when the lunar X appeared was around 16:23 on the 5th, and the best viewing time was around 17:00 to 18:00 . Interested members of the public are advised to use large-aperture astronomical telescopes (aperture of more than 10 cm) for observation and photography, so that the lunar X will appear larger and clearer.

Comprehensive sources: Xinhua News Agency, Science and Technology Daily, etc.

The cover image of this article comes from the copyright library. Reprinting and using it may cause copyright disputes