The January 2024 New Moon Will Be an Ultra-Thin Crescent Moon
By Graham Jones. Published 4-Jan-2024
The New Moon on January 11 will also produce the biggest solar eclipse ‘miss’ of 2024.
So near, so far. Unseen by us, the New Moon passes close to the Sun in the sky every month. But it only occasionally passes in front of the Sun and produces an eclipse. WARNING: Never look directly at the Sun.
©iStockphoto.com/JoyTasa
What Is a New Moon?
We generally say that New Moon is when the Moon passes between Earth and the Sun, and is 0% lit up as seen from Earth.
This is roughly what happens—but not exactly. If the New Moon passed exactly between Earth and the Sun every month, it would produce a solar eclipse each time. Instead, the Moon normally passes a little bit above or below the Sun in the sky.
January 2024: An Extreme Case
At New Moon on January 11, 2024, the Moon will ‘miss’ the Sun by a relatively large distance: 4.99°. This is around 10 times the width of the Sun in the sky, making it the biggest eclipse miss of the year.
As a result, it will also be the most illuminated New Moon of 2024. At the precise moment of New Moon—11:57 UTC—the Moon will be 0.19% lit up.
Strictly speaking, therefore, the January 2024 New Moon will be a vanishingly thin Crescent Moon.
An Invisible Moon
It is important to note that the thread-like crescent of the New Moon is invisible—it is utterly lost in the dazzling glare of the Sun.
WARNING: Never look directly at the Sun, and never point a telescope or binoculars in the direction of the Sun—it can cause serious and permanent eye damage in seconds.
Why It’s a Big Eclipse Miss
Solar eclipses happen when the Sun, Earth, and Moon come into alignment at New Moon.
This alignment doesn’t occur at every New Moon, because the Moon’s orbit is tilted by about 5°—as shown in the not-to-scale illustration below.
The plane of the Moon’s orbit around Earth is tilted to the plane of Earth’s orbit around the Sun. (A plane is a flat, two-dimensional surface: imagine a pancake with zero thickness.)
©timeanddate
At the New Moon of January 2024, the Moon is close to its farthest distance beneath the plane of Earth’s orbit—producing the biggest possible eclipse miss.
A Fraction of a Percent of Illumination
Likewise, the imperfect Sun-Moon-Earth alignment shown above is the reason the illumination of the Moon’s disk doesn’t quite drop to zero.
In fact, this happens to some extent at most New Moons. The following table shows how much of the Moon is lit up, as seen from Earth, at every New Moon in 2024.
Illumination of Moon’s Disk at New Moon, 2024
| Date | Illumination | |
|---|---|---|
| January 11 | 0.19% | |
| February 9 | 0.14% | |
| March 10 | 0.04% | |
| April 8 | 0.00% | |
| May 8 | 0.06% | |
| June 6 | 0.16% | |
| July 5 | 0.19% | |
| August 4 | 0.14% | |
| September 3 | 0.04% | |
| October 2 | 0.00% | |
| November 1 | 0.06% | |
| December 1 | 0.16% | |
| December 30 | 0.19% |
Sources: timeanddate.com, JPL Ephemeris DE430. All dates are UTC.
Two Perfect Alignments in 2024
There are two New Moons in the above table, on April 8 and October 2, when the Moon’s illumination drops to 0.00%. This is because there is a perfect alignment of the Sun, Moon, and Earth on these dates—which also means there is a solar eclipse.
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The New Moon of April 8 will produce a total eclipse across parts of Mexico, the United States, and Canada. Six months later, the New Moon of October 2 will produce an annular eclipse across Rapa Nui (Easter Island) and the southern tip of Chile and Argentina.