Don’t miss young moon and Venus after sunset (Neptune’s there, too)

How many of you have been watching the dazzling planet Venus – third-brightest celestial object, after the sun and moon – in the west at dusk and nightfall? If you haven’t seen it yet, just look in the sunset direction for this brilliant beauty to pop out some 45 minutes to an hour after the sun goes down. People with excellent vision might see Venus earlier, almost immediately after sundown.

And while you’re out there gazing at the moon and Venus, be aware of this. There are two other worlds in the west after sunset now.

First, look for Mercury, below Venus. Will you see Mercury? Maybe. It’s not as bright as Venus, and it’s closer to the sunset glare. You’ll need to look for very shortly after the sun goes down. Read more.

The third planet is Neptune. It’s very close to Venus on late January 2020 evenings, but not visible to the eye alone. On January 27, 2020, Venus and Neptune will stage the closest conjunction of any two planets this year. Read more.

So Mercury … maybe. Neptune … for those with telescopes. Meanwhile Venus and the moon will be easy to see. The picturesque sky scene begins on January 26, when the young moon will come into view close to the western horizon, below Venus. That’ll be a sweet scene to catch. Especially on January 26, don’t dally. The whisker-thin waxing crescent moon will set before nightfall on that date. In fact, from some places worldwide, you might need binoculars to tease out the lunar crescent from the glare of evening twilight on the 26th. No matter where you are on Earth, though, given an unobstructed horizon and clear skies, you shouldn’t have any trouble spotting the young moon at dusk/nightfall after the sun sets on January 27 or 28.

Want to know when the moon sets in your sky? Click on this Moonrise and Moonset Calculator.

From the Southern Hemisphere, the ecliptic (green line on our chart) will be slanted from upper right to lower left. Use Stellarium to get your location’s precise view.

The 2020 lunar calendars are nearly sold out! Order yours before they’re gone. Makes a great gift!

A very orange sky after sunset; Mercury can barely be seen as a fuzzy white dot in the glare.

Helio C. Vital caught the planet Mercury on January 21, 2020, when it was only 2 degrees above the western horizon after sunset. He wrote: “I used a Nikon CoolPix P900 camera to capture over the sea. Since I was holding it with my hands and contrast with the bright sky near the sun was very poor, the image exhibits a high level of noise.” Thank you, Helio!

A very thin threadlike waxing moon near the horizon, with a starlike planet to its right.

View at EarthSky Community Photos. | Dave Chapman of Nova Scotia, Canada, was vacationing in Cayo Coco, Cuba, on January 25, 2020, when he captured the young crescent moon with Mercury after sunset. He wrote: “The sky was clear but quite hazy, accounting for the redness of the sky.”

Will you spot Mercury? On January 26, 27 and 28, use the lit side of the lunar crescent to spot Mercury, the innermost planet of the solar system. The crescent will be pointing to Mercury, which is just now coming into view after sunset. You’ll likely need binoculars to spot it at evening dusk in late January 2020. Some people assume Mercury is very faint; that’s not so. Mercury is brighter than a 1st-magnitude star; it just seems faint because we nearly always see it against a bright twilight background.

Mercury will reach its greatest elongation from the sun on February 10, 2020. Use binoculars to spot Mercury all the sooner after sundown. Then try to spot it without your binoculars. Visit timeaddate.com and enter your location to find out when Mercury sets in your sky.

At this evening apparition of Mercury, the Northern Hemisphere enjoys a more favorable view than the Southern Hemisphere. From temperate latitudes in the Southern Hemisphere, Mercury will likely be particularly difficult to see, because this world sits deeper in the glare of evening twilight and sets sooner after sunset.

Very bright Venus and very faint Neptune against star field with stars and Venus labeled.

View at EarthSky Community Photos. | Dr Ski in Valencia, Philippines, caught Neptune near Venus on January 25, 2020. He wrote: “The conjunction of Venus and Neptune will occur 2 nights from now. But Neptune will be lost in Venus’ glare and very difficult to image. Venus is 60,000 times brighter than Neptune! Even tonight I cannot make out Neptune through my binoculars.” Thank you, Dr Ski!

The Venus-Neptune conjunction on January 27, 2020. As you enjoy the moon and Venus on these late January evenings, be aware that Venus, the sky’s brightest planet, is now pairing up with Neptune, the sky’s faintest planet. Neptune is the most distant major planet in our solar system. It’s the only solar system planet that you absolutely cannot see without an optical aid. This world is some six times fainter than the faintest star that’s visible to the unaided eye.

So you won’t see Neptune with the eye. But amateur astronomers with small telescopes have them trained on Venus already, watching for Venus and Neptune to stage the closest planetary conjunction of the year on January 27, 2020. At that time, these two worlds will be spaced only 1/12th of one degree apart. Photo opportunity indeed (for those with telescopes)! For some reference, the angular diameter of the moon spans about 1/2 degree, which is some six times greater than the tiny gap between Venus and Neptune.

Given that Venus outshines Neptune by about 60,000 times, it might be hard to glimpse Neptune in Venus’ glare at conjunction even with an optical aid. Venus will also be stunningly close to the 4th magnitude star Phi Aquarii at this time. Don’t mistake Phi Aquarii for Neptune. Phi Aquarii, though rather faint, is a good 30 times brighter than Neptune and can be seen by the eye alone on a dark night.

For many of us, it’ll be easier to view Neptune with an optical aid several days to a week after the January 27 Venus/Neptune conjunction. Venus will have moved away from Neptune, yet Neptune and the star Phi Aquarii will remain close together. This dim star will allow you locate Neptune, absent the glare of Venus.

Thin glowing rescent moon with dark part of moon faintly visible in earthshine.

Joe Kingore in Joplin, Missouri, caught the January 18, 2018 young moon with earthshine. What is earthshine? When the moon appears as a slender crescent in Earth’s sky, the Earth appears as an almost-full waning gibbous Earth in the moon’s sky. Earthshine is twice-reflected sunlight. That is, it’s sunlight reflected from the Earth to the moon, and then from the moon back to Earth. Read more.

Watch for earthshine, too. As you enjoy the lunar crescent on these late January 2020 evenings, note the soft glow of earthshine on the darkened portion of the moon. A moon with earthshine is not a moon in eclipse; no shadow or world in space is obscuring any other. Instead, you’re simply seeing the nighttime side of the moon, and, as it happens, the lunar night is covered over with earthshine: sunlight reflected from Earth to the moon. You know how a bright full moon can light up an earthly landscape? It’s the same on the moon, where a nearly full Earth shines now in the lunar night sky. On the moon, though, it’s earthlight that illuminates the scene. It’s that same earthlight (or earthshine, as we earthlings call it) you seeing on a waxing crescent moon.

Chart of curved track in the sky with planet Venus increasing in size and changing phase along it.

View larger. | Venus’ appearance in the evening sky from superior conjunction (August 14, 2019) to inferior conjunction (June 3, 2020). Chart by Guy Ottewell via his blog.

Bottom line: After sunset on January 26, 27 and 28, 2020, watch for the young moon and planet Venus in the west at dusk and nightfall. Use the lit side of the moon to locate Mercury, the innermost planet. If you have a telescope, use Venus to locate Neptune, the farthest planet.