Jupiter gives us Pluto in 2020

The king planet Jupiter is as hard to miss with the eye alone as the dwarf planet Pluto is difficult to find with the telescope. Jupiter is bright! It ranks as the fourth-brightest celestial object to light up the heavens, after the sun, moon and planet Venus. Pluto, on the other hand, is faint. It’s about 1,600 times dimmer than the faintest star visible to the unaided eye. It’s true that the best time of year to see Pluto through a small telescope is around the planet’s yearly opposition, when Earth is going between Pluto and the sun. That’ll happen this year on July 15-16, 2020.

However, this year – 2020 – is exceptional for Jupiter and Pluto. These two worlds are having a triple conjunction this year. They’ll come together, move apart, and come together again three times in 2020. Because all of these conjunctions will happen when these two planets are actually visible in our night sky (as opposed to being lost in the sun’s glare), this might be the best Jupiter-Pluto alignment for centuries to come.

This year, it should be easier to find Pluto throughout the year, because very bright Jupiter and very faint Pluto will remain near each other all year, closely aligned in front of the constellation Sagittarius. Pluto requires a telescope to be seen. No telescope? Try NASA’s Night Sky Network to find star parties and/or astronomy clubs near you. And you don’t need a telescope to use your imagination. Throughout 2020, dazzling Jupiter will enable us to envision Pluto with the mind’s eye on the sky’s dome. First find Jupiter and – presto – you’ve nearly stumbled upon Pluto. Just remember, Jupiter outshines Pluto by several million times.

The first of this year’s three Jupiter-Pluto conjunctions will take place on April 5. The second one will come on June 30, and the final one on November 12.

Where are these worlds now? Both Pluto and Jupiter have recently come out from behind the sun as seen from Earth. Both can be found in the east before sunup.

Of course, although Jupiter and Pluto nearly align along the same line of sight throughout 2020, these two worlds aren’t close together in space. Jupiter is a bit more than 5 astronomical units (AU) from the sun, while Pluto lodges way beyond Jupiter, in the Kuiper Belt, at about 34 astronomical units from the sun. One astronomical unit (AU) = one sun/Earth distance.

Jupiter’s and Pluto’s present distance in AU via Heavens-Above

Here’s some observational data about Pluto for 2020, from In-the-Sky.org

Two planets are said to be in conjunction whenever they reside north and south of one another on the sky’s dome. Conjunctions of Jupiter and Pluto recur in periods of 12 to 13 years. The previous Jupiter-Pluto conjunction happened on December 11, 2007, and the one before that on December 2, 1994. After 2020, the next Jupiter-Pluto conjunction will occur on February 4, 2033, and the one following that on April 12, 2045. But the gap between Jupiter and Pluto at each one of these conjunctions is quite far apart, and the conjunctions of 1994, 2007, and 2033 happen so close to the sun that even Jupiter is lost in the sun’s glare.

Far and away, 2020 presents the best alignment of Jupiter and Pluto in the 21st century (2001 to 2100). What’s more, Jupiter and Pluto stage three conjunctions this year, as Jupiter passes less than one degree north of Pluto at each conjunction on April 5, June 30 and November 12, 2020. (For reference, the moon’s angular diameter spans about 1/2 degree of sky.) All of these conjunctions in 2020 take place in front of the constellation Sagittarius, with Jupiter first passing Pluto on April 5 in prograde (going eastward in front of the backdrop stars), then sweeping past Pluto on June 30 in retrograde (going westward relative to the background stars), and then for the final Jupiter-Pluto conjunction on November 12 in prograde (eastward).

Most of the time, a Jupiter-Pluto conjunction in any year is a solitary event, as Jupiter laps Pluto going eastward, and never looks back. Triple conjunctions of Jupiter and Pluto – which occur over a period of about 7.4 months – are rare because Jupiter has to first catch Pluto going prograde (eastward), then in retrograde (westward) and then in prograde (eastward) again. The three-peat performance last happened in 1955-56 (November 2, 1955; February 8 and June 16, 1956), and will next occur in 2106-07 (July 13 and November 2, 2106; February 19, 2107). Yet, all three conjunctions in 1955-56 were widely spaced, and all three conjunctions in 2106-07 will be widely spaced, too.

In other words, as we said above, 2020 may well showcase the best Jupiter-Pluto alignment for centuries to come. Most excitingly, both Jupiter and Pluto will reach opposition in mid-July 2020. At opposition, a superior planet – any planet revolving around the sun outside of Earth’s orbit – resides opposite the sun in Earth’s sky.

At opposition, a superior planet (or superior dwarf planet) rises at sunset and sets at sunrise, and is out all night long. It’s at opposition that a planet shines at its brightest best in Earth’s sky, and it’s at or near opposition that a planet comes closest to Earth for the year.

Jupiter reaches opposition on July 14, 2020, at about 8:00 UTC, and comes closest to Earth on July 15, 2020, at about 10:00 UTC.

Pluto reaches opposition on July 15, 2020, at 19:00 UTC, and comes closest to Earth on July 13, 2020, at about 9:00 UTC.

In an uncanny bit of timing, the oppositions of Jupiter and Pluto happen almost concurrently in mid-July 2020. A planet reaches opposition midway through a retrograde. However, since Pluto resides so much farther from the sun than Jupiter does, Pluto’s retrograde lasts nearly 1 1/2 months (six weeks) longer than Jupiter’s four-month retrograde. So for near-unison oppositions, Pluto’s retrograde has to start – and end – approximately three weeks before – and after – Jupiter’s retrograde.

Jupiter and Pluto retrograde/opposition in 2020

Jupiter begins retrograde: May 14, 2020, in front of the constellation Sagittarius
Jupiter at opposition: July 14, 2020, in front of the constellation Sagittarius
Jupiter ends retrograde: September 13, 2020, in front of the constellation Sagittarius

Pluto begins retrograde: April 25, 2020, in front of the constellation Sagittarius
Pluto at opposition: July 15, 2020, in front of the constellation Sagittarius
Pluto ends retrograde: October 4, 2020, in front of the constellation Sagittarius

Jupiter-Pluto conjunction tables via Richard Nolle

Call it serendipity or synergy – or whatever – but the spectacular alignment of the king planet Jupiter with the dwarf planet Pluto doesn’t get much better than in 2020. A similarly good Jupiter-Pluto rendezvous might not happen again for a number of centuries to come.

Bottom line: Jupiter can help you find – or at lest envision – Pluto in 2020. That’s because these two worlds are having a triple conjunction this year; they’ll be near each other 3 times in 2020.

Source:
https://earthsky.org/astronomy-essentials/how-to-see-pluto-in-the-night-sky