Tonight

Moon, Jupiter, Saturn in late June

Moon, Jupiter, Saturn, plus Neptune and Pluto, in June 2021.
During the last week of June 2021, watch for the moon to sweep by the gas giants Saturn and Jupiter.

The moon, Jupiter, Saturn late night till dawn

Let the waning gibbous moon serve as your guide to the brilliant planets, Jupiter and Saturn, in the final week of June 2021. Late evening on June 25, 2021, you might catch the moon rsing above your eastern horizon before your bedtime. But there’s still a good likelihood of missing Saturn and Jupiter.

On the night of June 25-26, 2021, Saturn follows the moon into the sky roughly an hour after moonrise. Then Jupiter comes up an hour or so after Saturn. These bright gas giant planets, Jupiter and Saturn, are easy to view with the eye alone.

If you’re not one to stay up late, catch the moon with the Saturn and Jupiter in the predawn/dawn sky. Look for the moon closest to Saturn on or near the morning of June 27, and Jupiter one day later.

For the fun of it, on the sky chart above, we show the solar system’s most distant (known) planet, Neptune, as well as the dwarf planet Pluto. However, neither Neptune nor Pluto is visible to the unaided eye.

As the moon orbits Earth, moving eastward, it rises an average 50 minutes later with each successive night. If you’re not a night owl, you need to catch these three luminaries – the moon, Saturn and Jupiter – beaming together in the early morning sky.

Moonrise and moonset calculator for the USA and Canada via Old Farmer’s Almanac

Moonrise and moonset calculator worldwide via TimeandDate.com

Solar system bodies from Mercury to dwarf planets.
The world’s astronomers, under the auspices of the International Astronomical Union (IAU), have defined Pluto as a dwarf planet. In this artist’s impression the planets and dwarf planets are drawn to scale, but without correct relative distances. Find out the relative distances via Heavens-Above. Image via the International Astronomical Union (IAU).

Jupiter the King Planet

Jupiter, the king planet, is especially dazzling and hard to miss. Jupiter ranks as the 4th-brightest celestial body to adorn the sky, after the sun, moon and the planet Venus, respectively. Venus is a fixture of the evening sky, however. So there’s no way to mistake Venus for Jupiter, or vice versa. In short, Jupiter beams as the brightest star-like object in the morning sky!

Rising times of Saturn and Jupiter in the USA and Canada via Old Farmer’s Almanac

Rising times of Saturn and Jupiter worldwide via TimeandDate.com

Ringed planet Saturn

The ringed planet Saturn pales next Jupiter, with Jupiter outshining Saturn by some 16 times. Nonetheless, Saturn is easily as bright as a 1st-magnitude star. For the rest of this year, look first for blazing Jupiter and then seek out nearby Saturn.

By “nearby” we mean these two worlds are relatively close together on the sky’s dome. They are not particularly close together in space. Saturn is roughly twice Jupiter’s distance, as measured from Earth or the sun. Astronomers often give the distances of solar system bodies in terms of the astronomical unit (AU). One astronomical unit = sun/Earth distance of about 93 million miles (150 million km). At present, Jupiter and Saturn are about 5 AU and 10 AU from the sun, respectively.

Find out the present distances of the planets from Earth and the sun via Heavens-Above.

Moon, Jupiter and Saturn in the telescope

Novice at the telescope? If so, the moon, Jupiter and Saturn present exceptionally fine targets. Even with a modest, backyard variety of scope, these solar system bodies offer the most delectable eye candy.

It’s quite exciting to explore the lunar terrain along the lunar terminator – the dividing line between the lunar day and lunar night – where you have your best three-dimensional views the lunar mountains, craters and lowlands. If you don’t have a filter, it may be better to observe the moon in a twilight or daytime sky, at which time the lunar glare is not so overwhelming.

Jupiter’s moons

Jupiter’s four major moons – Io, Europa, Ganymede and Callisto – are easy to observe in any telescope. Historically, the explorer Captain James Cook (1728-1779) used these moons to determine longitude at various coastal locations as he traveled around the world. Of course, this method of determining longitude would only work on land, not the rough and tumbled seas. But then, using Jupiter’s moons to determine longitude on land provided a good double-check for the accuracy of the chronometer.

Read more: Here’s how to see Jupiter’s 4 largest moons

Jupiter and moons
Jupiter and its moons as seen through a telescope on August 15, 2009. Click here for the present position of Jupiter’s four major moons.

Astronomers knew from the get-go that Jupiter must be a super massive planet because these moons go so quickly around Jupiter. In fact, if an astronomer could figure out any moon’s orbital period and semi-major axis (mean distance from Jupiter), then it’s possible to calculate Jupiter’s mass.

How do astronomers know Jupiter’s mass?

Saturn’s rings

Last but hardly least, few sights can match the grandeur of Saturn’s glorious rings. Although all the outer planets of the solar system (Jupiter, Saturn, Uranus and Neptune) have rings, Saturn’s rings are in a class by itself.

Want to see Saturn’s rings. Read me 1st

These images suggest how the ringed planet Saturn might look when seen through a 4-inch telescope (top) versus an an 8-inch telescope (bottom). Image via SkyandTelescope.com.

If you’re not a night owl or a early bird, wait for a month or two, and these planets will be appearing in the evening sky before your bedtime. When these worlds reach opposition – sit opposite the sun in Earth’s sky – we’ll get to see them all night long. Saturn’s opposition comes on August 2, and that of Jupiter on August 20.

In the meantime, if you’re an early bird, let the moon show you the bright morning planets, Jupiter and Saturn.

Posted 
June 25, 2021
 in 
Tonight

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