Venus is becoming a thinner crescent — and that’s when it finally starts making sense
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Venus is something of a frustration for stargazers. It’s the brightest planet and the easiest to see, while the sight of it close to a crescent moon is one of the most achingly beautiful sights in the sky. Yet it gives almost nothing away.
Mars has its reddish color. Saturn rewards even a small telescope with its spectacular rings. Jupiter has moons, belts and an obvious disk. Venus, meanwhile, spends months blazing away in twilight looking exactly like what people who do not stargaze assume a star should look like — a brilliant white point. What we’re seeing is sunlight reflected by its global cloud cover, which in turn makes it impossible to see in any detail.
But every now and then, it does something revealing by becoming a crescent. That is when Venus, an inner planet relative to Earth, finally makes sense.
Put a small telescope on Venus this week and its appearance is completely different from the dazzling dot seen with the naked eye. This week, its disk will dim from 36% to 32% lit as it shrinks toward a thinner crescent as September progresses. At the same time, its apparent disk is getting larger because Venus is moving closer to Earth.
Those two changes are connected. Venus reached its greatest eastern elongation, about 46 degrees from the sun, on Aug. 15. It’s now swinging around the inside of its smaller, faster orbit of the sun towards inferior conjunction on Oct. 24, when it will pass roughly between Earth and the sun, and be lost in the sun’s glare. Before that, it will reach its peak — greatest brilliancy — in the evening sky on Sept. 18, shining at magnitude -4.8 while just 26% lit. That’s the sweet spot, when its increasing angular size and decreasing crescent combine at their brightest, as seen from Earth (though its modeled visual brightness peaks a few days later, around Sept.22). After that, it becomes an increasingly dim crescent.
Seeing Venus as a crescent makes the geometry beautifully obvious. We are no longer looking across the solar system towards the brightly illuminated side of Venus. We are increasingly looking at the planet from behind, towards its night side, with sunlight catching only one edge.
It is almost the same idea as a crescent moon — except Venus is another world tens of millions of miles away. As it passes roughly between Earth and the sun on Oct. 24, it will be 0.27 AU away — equivalent to 25 million miles (40 million kilometers). At its farthest, Venus can be 162 million miles (261 million kilometers) from Earth.
The phases of Venus were historically important. When Galileo observed Venus through a telescope in the early 17th century, seeing it display a broad range of phases helped demolish the traditional Ptolemaic model in which Venus was supposed to orbit Earth in a way that could not produce the full sequence he observed.
Four centuries later, the same observation remains one of the simplest ways to understand our place in the solar system.
Venus becomes far more interesting when it stops looking its best through the naked eye and instead becomes a “wow” moment in a small telescope. As the “Evening Star” sinks lower into twilight, we’re not just seeing a crescent — we’re seeing a planet orbit the sun.
What’s happening and when to look
Venus remains an evening object throughout September, but it is rapidly becoming more challenging from mid-northern latitudes. Look very low towards the west-southwest shortly after sunset, where it should be obvious because practically nothing else in the twilight comes close to its brilliance.
Do not search for Venus with a telescope or binoculars while the sun is still above the horizon. Wait until sunset and make sure the sun has disappeared before pointing optical equipment anywhere near the western sky.
Venus will move through Virgo during the coming days before a particularly attractive conjunction on Sept. 14, when a 16%-lit waxing crescent moon will pass extremely close to a 29%-lit Venus. Two crescents together.
How and when I’m watching it
Venus is one of those objects I prefer to revisit several times rather than observe once. A single look shows a crescent, but observing every week reveals movement.
I’ll mostly use my small spotting scope in the front yard to look at Venus as a crescent this month, but if I’m short on time, I’ll use some 10×50 binoculars, which can also reveal the phase. The trick is not to expect surface detail — just a clean geometric shape.
Atmospheric turbulence near the horizon can make Venus wobble and shimmer, but its phase usually cuts through.
Stargazer’s corner: Sept. 4–10, 2026
With the moon now past last quarter, the early evening sky is finally free from bright moonlight. It’s an excellent opportunity to revisit the Milky Way, along with star clusters, nebulas and other deep-sky objects before autumn gradually takes over and its bright center slumps into the horizon. Before dawn, the waning crescent moon moves through Taurus, passing close to Mars on Sept. 6 in Gemini, while brilliant Venus continues to dominate the western twilight after sunset. The dazzling planet remains the unmistakable evening beacon, shining low above the west shortly after sunset. Saturn, meanwhile, continues to brighten in the east during the late evening, making this an increasingly good time to point binoculars or, better still, a small telescope toward the ringed planet.
Constellation of the week: Pisces
Pisces is easy to overlook. Its faint stars form two celestial fish joined by a long cord, creating a broad V-shape beneath the easy-to-find Great Square of Pegasus in the eastern evening sky after dark this month.
This week is a great time to find it because Neptune soon reaches opposition within Pisces, making the distant planet brighter than at any other time this year. Although Neptune needs binoculars or a telescope to spot it, learning the constellation
Pisces has been associated with mythology and water for thousands of years, but finding its subtle pattern also signals that the autumn constellations are beginning to take over the night sky.
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