Vietnam welcomes 'new moon' in October: What's interesting?

'New Moon' is considered the invisible phase of the moon in the sky. Many Vietnamese astronomy enthusiasts take advantage of this day to do interesting things.

According to the Hanoi Astronomical Society (HAS), during the "new moon" or new moon, the moon will be on the same side of the earth as the sun and will not be visible in the night sky. This phase occurred recently on October 3, at 1:51 a.m. (Vietnam time). This is the best time of the month to observe faint objects such as galaxies and star clusters because there is no moonlight to interfere.

Moonless nights are a good time to observe faint objects such as galaxies and star clusters.

PHOTO: HUY HYUNH

Space.com reports that during the "new moon" phase, the moon's brightness is 0% and gradually increases through many lunar phases (moon phases), until the full moon phase, when the moon's brightness is 100%. The phases of the moon show the passage of time in the night sky. Some nights when we look up at the moon, it is full and bright. Sometimes it is just a silvery streak. According to experts, these changes in "appearance" are the phases of the moon. As the moon orbits the earth, it goes through eight distinct phases.

What is the difference between a full moon and a new moon?

A new moon is the “invisible phase of the moon,” according to NASA , because the moon’s illuminated side is facing away from Earth, toward the sun. The moon is also in the sky during the day, and without the Earth-facing side being illuminated by the sun, observers wouldn’t be able to see it. According to Space.com , the significant difference lies in the percentage of illumination on the Earth-facing side. During the new moon phase, the percentage is 0%, and it becomes 100% during the full moon, about 14 days later.

The phases of the moon show the passage of time in the night sky.

PHOTO: HUY HYUNH

Thanks to the regular repetition of these moments, the lunar phases have been the basis of the lunisolar calendar since ancient times. However, it is difficult to determine the exact moment of the new moon, so many ancient civilizations began the lunar month with the appearance of the first crescent after sunset.

Last days to see comets in early October

During this new moon phase, many Vietnamese astronomy enthusiasts will spend time observing comet C/2023 A3, before it temporarily disappears from the morning sky. But very quickly after that, it will return to the afternoon sky from October 13 with a more impressive performance. October 3: Although the brightness continues to increase, however, at this time, observing C/2023 A3 is much more difficult when it is not higher than 9.5° above the horizon before sunrise. It will rise from after 4:40 am in the east. At this time, the comet is 0.686 AU from the Earth and is on its way closer to our planet. October 4: C/2023 A3 will move to the Virgo constellation at the end of October 4. So, on this morning, you'll find it near the "border" between the constellations Virgo and Leo. It will be about 8.5° above the horizon with an apparent magnitude of 2.5. In fact, with viewing conditions close to the horizon, an object can be 2 to 3 magnitudes dimmer, so using a pair of binoculars will help you find this comet more easily. October 5: At just 6° above, C/2023 A3 is almost completely submerged in the new day light and can only be seen briefly if you use binoculars or a telescope pointed close to the horizon. However, if predictions are correct, this is when the comet begins to brighten rapidly as its brightness is enhanced by the forward scattering effect. October 6: Rising after 5am, meaning you only have about 15-20 minutes to observe before dawn, C/2023 A3 officially says goodbye to observers in Vietnam in the morning sky.

Thanhnien.vn

Source: https://thanhnien.vn/viet-nam-don-trang-moi-thang-october-co-gi-thu-vi-18524100217334394.htm