Venus was in inferior conjunction on August 13, in the dividing line between Earth and the Sun. It is now swinging away from this line, speeding ahead of Earth in its faster orbit.
In fact, Venus has been appearing in the eastern morning sky for the past two weeks. When September opened, the brilliant “morning star” rose just before the first glow of dawn at approximately 4:30 a.m. local daylight time. But as each morning passed, Venus rose ever higher, and became a little brighter; It will reach its peak on September 19, when it will appear at a stunning magnitude of -4.8. This is it 23 times brighter As the brightest star in the sky, Sirius (in Canis Major, Big Dog), is seven times brighter than the second brightest planet, Jupiter.
By the end of the month, it will rise before 3:30 a.m. and will precede the sun by about three and a half hours!
Related: Night sky September 2023: What you can see tonight (maps)
Try looking for Venus by the brightness of the daytime sky. This can be done if you know exactly where to look.
Perhaps the best way is to keep them in sight even after sunrise. At its current extreme brightness, it is often seen as a small white speck against the blue background of daylight.
Those who live in rural areas away from any outside light report that Venus is able to cast a faint but clear shadow.
Greatest luminous range
For many years, almanacs and astrological calendars indicated the date on which Venus reached its peak brilliance: “Venus in greatest splendor.” But starting in 2009, a new type of nomenclature has emerged to describe this event: “Venus at maximum illuminated.”
When Venus appears as a full or almost completely illuminated disk, it appears rather small in angular size through telescopes. This is because Venus is located on the opposite side of the Sun as seen from Earth, about 160 million miles (257 million km) away. Conversely, when Venus passes close to Earth—26 million miles (42 million kilometers)—its disk swells enormously; Approximately to 1/30 of the apparent size of the full moon. But since most of Venus’s dark side is directed toward Earth, all we can see of it is, at best, a very thin crescent, of which perhaps only a small portion is illuminated by the Sun.
Somewhere between these two extremes is a compromise, where Venus appears relatively large, while exposing much of the illuminated portion of its disk. This comes as Venus’ disk appears to be a quarter illuminated – much more than if it were just a hair crescent – and at the same time, it is located about 41 million miles (66 million km) away from us and its apparent disk size is about 41 million miles (66 million km) two-thirds away. That’s when it looks bigger.
Thus, the greatest illuminated extent of Venus’ disk coincides with its greatest brilliance.
Interestingly, its peak brilliance this month is not limited to just one day, but extends from September 16 to September 26. So, through a telescope during the month of September, it shows a large, brilliant, beautiful crescent moon that is waxing in all its phases. A month while it shrinks in size.
When September opened, Venus was only 12% illuminated, but by the end of the month, that number would rise to 36%; But as it recedes 17 million miles (27 million km) from Earth, it will appear about a third smaller than it did at the beginning of the month.
Meetings of planets, star and moon
On the same morning that Venus is at its brightest (September 19), wait until about an hour before sunrise, and then using your clenched fist at arm’s length (which is 10 degrees wide), move roughly “two fists” to Venus below Left to view the faint planet Mercury, the smallest planet in the solar system.
Also, over the coming weeks, Venus will also approach the bright, first-magnitude star Regulus in Leo. By the end of this month, Venus and this bluish star will be separated by about 8 degrees.
On October 10, when Venus passes about 2.5 degrees below Regulus, a beautiful crescent moon will pass just north of both star and planet and will form an eye-catching formation in the dawn sky.
If you’re hoping to catch a glimpse of Venus, our guide to the best binoculars is a great place to find some wide-angle optics that can give you a beautiful view of the planet on the go. But if you want to get a closer look at Venus’ thin crescent in the night sky, check out our guides to the best telescopes or the best budget telescopes.
And if you’re looking to take photos of Venus or the night sky in general, check out our guide on how to photograph planets, as well as our best cameras for astrophotography and best lenses for astrophotography.
Oldie, but good
The idea of seeing the crescent of Venus always reminds me of a funny story told by George Lovy (1939-1993), a well-known astronomy lecturer and author, who was also a good friend of mine. I’ve told this story on Space.com before, but it’s worth telling it again.
One night, while George was running a public night at the Brooklyn College Observatory in New York, the telescope was pointed directly at Venus which was – then then – displaying its delicate crescent shape. However, one student, peering through the telescope’s lens, stubbornly insisted that he was not looking at Venus, but at the Moon instead. When George commented that the moon was not in the sky, the student replied: “So what? Doesn’t the telescope show you things you can’t see without it?”
Joe Rao is an instructor and guest lecturer at New York University Hayden Planetarium. He writes about astronomy Natural History Journalthe Farmers Almanac And other publications.
Editor’s note: If you’ve taken a photo of Venus and want to share it with Space.com readers, send your photo(s), comments, name and location to email@example.com.