Astronomy Essentials

Venus at greatest elongation on October 29

Venus at greatest elongation: Sky chart of bright Venus and many labeled constellations and stars.
View larger. | Venus at greatest elongation – farthest from the sun on the sky’s dome – on October 29, 2021. Look west after sunset. If you have a dark sky, notice the famous Teapot in Sagittarius – and the faint stars of Ophiuchus the Serpent Bearer – shifting into the sunset behind Venus. Scorpius (on the horizon on this chart) is very near the sunset glare now. Check out the photo below. Image via Stellarium.

Venus at greatest elongation

Venus is the brightest planet seen from Earth. And it’ll be a beautiful and interesting world to watch through the end of 2021. Look west after sunset for Venus. You can’t miss it. It’s dazzling! That’s even though, from the Northern Hemisphere, the autumn angle of the ecliptic keeps Venus to the left of the sunset point, not high above the sunset. From the Southern Hemisphere, Venus is gloriously high above the sunset all month. And, for all of us, Venus reaches its greatest elongation – farthest point from the sunset – on October 29. Venus at greatest elongation appears 47 degrees from the sun, its maximum possible distance.

Venus ranks as the third-brightest celestial body to light up the heavens, after the sun and moon. On any evening between now and late December, it’ll be the first “star” to pop into view. Venus is currently getting brighter as the weeks pass. Its greatest illuminated extent – heralding its time of greatest brilliancy for this evening apparition – will take place in early December 2021.

By then, Venus will appear much closer to the sunset, even lower in the sky, as an eerie bright light. UFO sightings will increase around that time!

All in all, Venus will make quite an impression before 2021 ends, for all of us on Earth.

Annotated sky photo, showing Venus and the stars of the Teapot and Scorpius.
View at EarthSky Community Photos. | Pradnya Gharpure in Nagpur, India, captured Venus – and the stars around it – on October 22, drew in the constellation lines, and wrote: “I had been fascinated by the Teapot asterism and the Scorpius constellation when I first clicked them with Jupiter and Saturn nearby in 2020. This year, I watched them again through the summer. Finally, as winter begins to set in, we’re now getting clear skies, and today I took my tripod to get a click! Scorpius was about to set and the tail end stars had already faded into the city lights … But it was quite stunning to see the peculiarly shifted orientation of the 2 star groups as opposed to what I’d seen before. Venus shone brightly, adding to the whole magnificence!” Thank you, Pradnya!

Venus is easy to see

Just look west after sunset for Venus – to the left of the sunset from the Northern Hemisphere – straight above the sunset from the Southern Hemisphere. You can’t miss the brightest planet.

Venus is so bright that some sharp-eyed people have been known to see it in a daytime sky. That’ll happen most often around early December, when Venus is at its brightest. But it’s possible now, too. Most of us, though, will have to wait until after the sun goes down to see this blazing planet. Then watch out! Venus’ brightness and distance from the sun in late October 2021 will dazzle you.

Venus comes to its October 29 greatest elongation in front of the constellation Ophiuchus the Serpent Bearer. Ophiuchus is sometimes called the 13th constellation of the zodiac because the sun, moon and planets all pass within its boundaries at times.

Diagram with slanted ecliptic and almost vertical ecliptic with text annotations.
At sunset on the spring equinox, the ecliptic – pathway of the sun, moon and planets – hits the sunset horizon at its steepest angle of the year. But at sunset on the autumn equinox, the ecliptic hits the sunset horizon at its shallowest angle. Therefore, when Venus at greatest evening elongation is around the time of the fall equinox, Venus is near the horizon. Image via Dominic Ford/

Venus setting times

As mentioned above, for this October 2021 elongation, the farther north you live, the shorter the time Venus will stay out after sunset. And the farther south you live, the longer. Here is the approximate setting time for Venus at various latitudes:

60 degrees north latitude (Anchorage, Alaska, for example): Venus sets about 30 minutes after sunset (and is only about a degree above the horizon)
40 degrees north latitude (Denver, Colorado, for example): Venus sets about 2 and a half hours after sunset
Equator, 0 degrees latitude (Singapore, for example): Venus sets about 3 hours and 15 minutes after sunset
40 degrees south latitude (Wellington, New Zealand, for example): Venus sets about 4 hours after sunset

Want more specific information? Click here for a sky almanac.

Spring versus fall elongations

Springtime elongations of Venus (or Mercury) are always best. At such times, Venus is always above the sunset. Autumn elongations aren’t as glorious because then Venus’ distance from the sun is mostly sideways, along the horizon. Why the difference?

The angle of the ecliptic is what determines how high or low Venus is after sunset. That angle is low to the horizon in autumn and steep in spring. The sun, moon and planets all travel on the ecliptic. So, when a greatest eastern elongation happens in spring, the planet appears farther above the horizon and is visible for longer in a dark sky. When a greatest eastern elongation happens in the fall, the planet is closer to the horizon and appears for a shorter time in a dark sky. That’s what’s happening for us in the Northern Hemisphere at this October 2021 greatest elongation.

The reverse is true for greatest western elongations, or when an inner planet is farthest from the sun in the morning. For a morning elongation of Venus, the ecliptic makes its steepest angle to the horizon at the autumn equinox, and its shallowest angle to the horizon at the spring equinox.

As the angle of the ecliptic to the horizon gets wider as we move away from Northern Hemisphere’s fall equinox, Venus will appear higher above the horizon. The planet reaches its highest altitude on 2021 evenings on December 9. That’s shortly after Venus will reach its greatest illuminated extent (greatest brilliancy) on December 3.

So keep watching Venus. It’ll remain beautiful and fascinating into December!

Diagram of two concentric orbits showing line of sight views of Mercury from Earth.
An inferior planet – a planet that orbits the sun inside of Earth’s orbit – appears in the evening sky at its greatest eastern elongation, and in the morning sky at its greatest western elongation. The two inferior planets are Mercury and Venus, residing at a mean distance of 0.387 and 0.723 astronomical units from the sun, respectively.

Bottom line: At greatest eastern elongation on October 29, 2021, Venus is as far from the sun as it will be for this evening apparition. It’ll be a prime viewing target after sunset this month, and an interesting planet to watch between now and the end of the year. Venus appears better the farther south you live.

October 29, 2021
Astronomy Essentials

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Kelly Kizer Whitt

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