In an unofficial sense, I’d like to call today (April 10) “Planet Imaging Day.”
There will be two planets appearing very close together in the early morning hours, and later that day in the early evening sky we will have the chance to see Jupiter hovering near a thin, waxing crescent moon and turning into a star. It’s quite an eye-catching sight. There will be other celestial objects to be seen and found among the brightest planets in the night sky.
Here are some interesting details about these upcoming meetups.
Mars and Saturn
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These two “superior” planets (planets whose orbits are farther from the sun than Earth) are currently visible near the east-southeastern horizon, about 30 to 40 minutes before sunrise. Binoculars will certainly be helpful in locating them against the bright twilight sky.
Both planets will be nearly identical in brightness, separated by only 0.02 magnitude. The brighter Saturn (magnitude +1.14) will shine calmly below Mars (magnitude +1.16), the two worlds being separated by only half a degree, equal to the apparent width of the moon. (The closest approach to each other comes after sunrise, just over four-tenths of a degree across much of North America.) If unsettled weather prevents you from seeing the pair on Wednesday, April 10, they’ll barely be visible. The next morning they will be the same distance apart, but Mars will have shifted to the upper left corner of Saturn.
If you use a telescope equipped with a low-power eyepiece, you can fit both planets in the same field of view. In addition to being almost the same brightness, the contrast in their colors is quite striking; Mars shines pumpkin-colored compared to golden Saturn.
An example of these meetings
Saturn, which is approximately 886.2 million miles (1.42 billion km) away from the sun, takes 29.46 years to orbit the sun. At an average distance of 141.6 million miles (227.8 million km) from the sun, Mars takes only 1.88 years to complete a journey around the sun. As a result, Mars’ normal eastward motion between the stars is much faster than that of Saturn. Therefore, from our vantage point on Earth, Mars will appear to periodically pass Saturn in the sky.
Interestingly, when we combine the movements of Earth, Mars, and Saturn, we find that the interval between Mars-Saturn conjunctions is on average every 2 years and 7 days. In the table below we list all these conjunctions from 2018 to 2030. Note that the upcoming conjunction will be the second closest conjunction in this twelve-year interval (albeit almost as close as the one in 2022).
Jupiter is next to the crescent moon
Soon it will be time to bid a fond farewell to an object that has been a fixture in the evening sky since mid-autumn: the planet Jupiter.
Jupiter is leaving our skies after months of impressive display. It currently sets about two hours and 20 minutes after the sun, and although it’s pretty low in the western sky, you can see it fairly easily even 30 to 40 minutes after sunset. It is the brightest “star” in the region.
On Wednesday evening, 2.3 days after the new phase (and solar eclipse), we will be treated to a beautiful celestial picture with a very narrow crescent moon located about 4 degrees to the lower left of Jupiter, only 7 percent illuminated. . Remember that your clenched fist held at arm’s length is roughly 10 degrees. So Jupiter and the Moon will appear to be separated by a little less than half a fist. The thin band of the moon tilted slightly to the right will almost appear to mimic the grin of the invisible Cheshire cat in Lewis Carroll’s “Alice in Wonderland.”
Stunning World Light!
Be sure to keep an eye on the moon to see if you can spot the phenomenon known as “Earthlight,” more popularly known as “The old moon in the arms of the new moon.”
This is the light that travels from the Sun to the Earth, is reflected upwards towards the moon, and then returns back to the Earth; “triple journey”. Binoculars will reveal this effect better than seeing it with the naked eye. Earth’s light is quite weak because only a small fraction of the sunlight reflected from Earth hits the Moon. Because the Moon is such a poor reflector, it reflects only 7 percent of it back into space, and only a small portion of it returns to Earth. Viewed through binoculars, the effect can be quite striking; The moon looks like an almost three-dimensional ball of eerie yellow and bluish gray.
Now add Jupiter to the upper right of the moon, shining like a silvery jewel, and you have a truly stunning sight. And as a bonus, the beautiful Pleiades star cluster will shine 8 degrees above the moon. Make sure your western sky is clear of obstructions such as nearby buildings or trees so you can see everything with a single glance.
And maybe a comet too!
And if nature is in the mood to show off, there’s one more object you can try to find. This would be comet 12P/Pons-Brooks, which would be located about 6 and a half degrees below the Moon and 4 degrees to the lower right of Jupiter.
The comet should now be near its peak at magnitude +4.6; Maybe vaguely visible to the naked eye from a dark place, but definitely accessible with good binoculars or a small telescope. Visually, the comet should appear as a circular, wispy patch of light, possibly projecting upwards from a faint tail of gas and to the left of its small bright tip (the head of the comet).
goodbye for now
With each passing evening, Jupiter will sink further below its sunset glow. As of April 23, the difference between sunset and Jupiter’s setting will be reduced to 90 minutes. By April 30, Jupiter will hover just 5 degrees above the western horizon a half-hour after sunset. The big world sets about an hour after the sun and becomes increasingly difficult to see in the bright twilight glow.
By May 4, Jupiter will be gone. It will be in conjunction with the sun on May 18, transitioning into the morning sky and reappearing at dawn in early June.
So for Jupiter, it’s not really a “goodbye”, just a “goodbye” until late spring. As American writer Richard Bach so aptly put it:
“Do not be dismayed by farewells. A farewell is necessary before we meet again.”
Editor’s Note: If you take a great photo of Jupiter, the Moon, Saturn, or Mars and want to share it with Space.com readers, submit your photos, comments, and your name and location to Space.com. spacephotos@space.com.
Joe Rao is an instructor and visiting professor in New York Hayden Planetarium. writes about astronomy for Natural History magazine, Farmer’s Almanac and other publications.