Chapter 93: The Beauty of the Moon (Part 1)

Men have joy and sorrow, parting and reunion; the moon has its waxing and waning, its fullness and emptiness.
Raise the cup and invite the bright moon; our shadows make three.
When life brings us joy, we should revel in it fully; do not let a golden goblet stand empty while we face the moon.

For as long as humanity has existed, it has held a special tenderness for the Moon, and legends and poems about her are beyond counting.
In Chinese culture, those tales are mostly gentle and beautiful—such as the Mid-Autumn Festival, symbol of reunion, and the tale of Chang’e ascending to the moon, emblem of love.
In the West, by contrast, the moon tends to carry darker figures—vampires, werewolves, and the like.
But to most people today, it is simply Earth’s satellite, the sun of the night.
To astronomy enthusiasts, however, the moon is beautiful and mysterious.
Because it is close to Earth and easy to observe, many amateur astrophotographers choose it as their first subject. Lin Nan was no different.

After his failed attempt to photograph the moon, Lin Nan pulled out his phone to check some lunar information, hoping to see whether it was the moon’s own turn that had gone wrong.
Instead, the mountain signal was too weak—the web pages would not load at all.
After a while he said to his father, Lin Lang, “Dad, we can’t get shots tonight. We’ll have to wait for the next proper moon night. But summer vacation is coming soon, and we’ll have plenty of time then. I’ll use this period to strengthen my astronomy basics.”

Lin Lang was genuinely pleased to see his son starting from the fundamentals.
He didn’t understand astronomy himself, but he knew that every discipline is built on a firm foundation.
Every tall building rises from a stable base.
Then Lin Lang and Ye Xinlan reminded Lin Nan to get to bed early and returned to their room.

After they left, Lin Nan immediately removed the telescope from the equatorial mount and began observing the sky.
He knew every astrophotographer begins this way: by seeing the sky and learning its patterns.
You must know it before you can photograph it.
He realized he had been a little too ambitious, wanting to shoot immediately.
Still, it was not too late to start observing.
Tonight’s moon was large and bright, yet even in that glow Sirius, the brightest star in the night sky, could still be seen.

He remembered reading files in his astronomy group: he even recalled the precise numbers used by humans to classify celestial bodies.
Across the whole Earth, only just over six thousand stars are visible to people with normal eyesight.
Astronomers classify stars by magnitude: there are 20 first-magnitude stars, 46 second-magnitude, 134 third-magnitude, 458 fourth-magnitude, 1,476 fifth-magnitude, and 4,840 sixth-magnitude stars.
A first-magnitude star is the brightest; a sixth-magnitude star is the faintest the average human eye can barely detect.
The two differ by five classes, a factor of about 100 in brightness, while stars in adjacent classes differ by about 2.51 times.

At any given moment we can see only a little over three thousand stars above the horizon; another three thousand lie below it, hidden from sight.
Veteran members in the group had said that when learning the sky, one should first recognize the sixty or so relatively bright first- and second-magnitude stars, then gradually tackle some third and fourth ones; the very dim fifth and sixth can be set aside for now.
In other words: easy first, hard later, step by step, little by little.
Only then can the whole visible sky—and the universe you can actually see—become familiar.

The stars visible to the naked eye are divided by scientists into regions according to their apparent groupings, and those regions are called constellations.
As early as around the first millennium BCE, the ancient Babylonians had established 30 constellations.
Later, European astronomers added to and developed them further.
In 1922, the International Astronomical Union standardized these historical names into the modern set of 88 internationally recognized constellations—29 in the northern sky, 12 on the zodiac, and 47 in the southern sky.
Shortly thereafter it fixed the reference to the spring equinox and celestial equator of 1875.
Constellations vary in size and shape, but every star in a given region belongs to that constellation.
For example, seven bright stars arranged like a ladle make up the Big Dipper, known as Ursa Major.

Constellation names are usually inspired by the stars’ patterns and human imagination: mythic figures such as Andromeda and Cassiopeia, instruments like Sextans and Microscopium, or animals like Cetus the Whale and Corvus the Raven.
The naming system most commonly used by astronomers comes from Johann Bayer’s early seventeenth-century proposal: each star is assigned a designation by its constellation name plus a Greek lower-case letter in order of brightness—Alpha, Beta, Gamma, Delta, Epsilon, Zeta, and so on.
After all 24 Greek letters are used, Latin lower-case letters a, b, c, d follow; if still insufficient, Latin upper-case A, B, C, D are used, with letters after R set aside especially for variable stars.

The people of ancient China had long noticed bright or distinctive stars and gave them many names—Vega, Altair, the Great Fire Star, Heart Star Two, Antares, and so on.
Since Vega and Altair are the brightest stars of Lyra and Aquila, they are also known as Alpha Lyrae and Alpha Aquilae.

With the strength of youth in his memory, Lin Nan had committed all these basics to heart.
Yet knowledge on paper was one thing; standing under the sky was another.
Against the dark curtain of night, the points of light blurred into mere glittering dots—he still could not tell which was which, nor which belonged to which constellation.
At that moment he could only identify the Big Dipper.
Anyone could do that, of course.
So that night he kept observing through the telescope, trying hard to align what he saw with what he had memorized.
His results were meager: he found only a few stars with very obvious features, and could not identify most of them.
Near midnight, he gave up and went to sleep.

He knew astronomy was not a craft acquired overnight, much like basketball: rushing toward mastery often means moving too quickly and failing.

As for Si Fangxiang and his daughter Si Dong, the pair at the villa, they drove home after photographing the full moon.
Unlike Lin Nan, Si Dong had amassed quite a lot of astronomical knowledge under her father’s guidance since childhood.
She knew the full moon is the worst time to photograph the moon, and also one of the poorest times for star imaging.
Still, a full moon occurs only once a month, and this month happened to be the fifteenth, so Si Dong could only come with her father to watch it.

With his unusually quick learning pace, after returning to school Lin Nan, within a week, had almost a full understanding of the Moon.
Only then did he realize he had been a fool to choose to shoot at the full moon near midmonth.

First, the moon changes phase continuously as it moves around Earth.
Its sidereal orbital period is 27.3 days; the synodic cycle of lunar phases is 29.5 days.
Its changing faces can be reduced to eight basic phases: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent.
They alternate in order and repeat endlessly, forming a complete lunar month.
Through lunar observation, astronomy enthusiasts can generally discern features such as craters, maria, rilles, valleys, and mountain ranges.

Craters are formed by meteor impacts or volcanic activity—simply put, raised rims with depressed centers.
There are so many that they seem innumerable: more than 33,000 lunar craters larger than one kilometer exist, covering about 7 to 10 percent of the moon’s surface.
Under IAU rules, lunar craters are usually named after famous astronomers or other scientists, such as Copernicus Crater, Archimedes Crater, Newton Crater, and Kepler Crater.
Among them are a few named after ancient Chinese scholars: Zhang Heng, Zu Chongzhi, Guo Shoujing, and Shi Shen.
Wan Hu Crater was the first lunar crater named with a Chinese person’s name.

The lunar maria are vast ancient impact basins later flooded by lava, making broad lowlands.
Some smaller plains are called marshes.
Rilles and valleys are small surface fractures; their forms are oddly varied and demand sharp eyes, making them especially compelling targets for enthusiasts.
As for mountain ranges, these are elongated elevated structures of several ridges and valleys running broadly in the same direction.
Like craters, most lunar mountain names are borrowed from their terrestrial counterparts.
Notable ones include the Apennine Mountains: lying near the lunar center, the longest range on the Moon, rising 3 to 4 kilometers above the maria and winding for about 1,000 kilometers.
Leibniz Mountains: near the lunar south pole, with peaks reaching 9,000 meters—high enough to make Mount Everest seem modest by comparison.
The Lunar Alps: not as colossal as Earth’s Alps, yet their alternation of peaks and deep valleys creates a distinct and striking beauty.

Reading about those ranges, Lin Nan could not help imagining that someday, if someone were to climb on the Moon, it would almost certainly be easier than climbing Everest.
They are high, yes—but lunar gravity is weak. A few leaps might even carry you right to the top, he thought with a laugh.

From his new understanding of lunar phases, Lin Nan also understood why he had managed to capture only the moon’s outline.
At full moon, the moon and the sun are exactly 180 degrees apart: the sun sets in the west, the moon rises in the east, and it stays visible all night.
So although the whole lunar landscape is exposed, full-moon sunlight strikes it head-on, bleaching the near side into a flat, ghostly white.
In astrophotography terms, it lacks depth; the eyes grow tired very quickly.
Beyond admiring the dark maria and the bright radial rays of Tycho and Copernicus, there is little subtle detail left to savor.
With Lin Nan’s beginner-level equipment, rough shooting technique, and not-yet-smooth handling, he ended up unable to capture anything meaningful.
So he set himself to study the other seven phases in earnest.