2020, November 2: Jupiter – Saturn Heliocentric Conjunction

2020, November 2: Jupiter passes Saturn in a heliocentric conjunction, as viewed from outside the solar system.

As the Great Conjunction of Jupiter and Saturn nears, Jupiter passes Saturn if viewed from the sun.

by Jeffrey L. Hunt

As Jupiter edges closer to Saturn in the evening sky of Earth, Jupiter passes Saturn as viewed from outside the solar system on November 2, 2020.  This is known as a heliocentric conjunction.  The next one for these two planets is on December 7, 2040.

If we were on Jupiter on November 2, we would say that Saturn is at opposition.  Saturn is in the opposite direction in the sky from the sun.  If we were Saturnians, then we would say that Jupiter is at inferior conjunction, between Saturn and the sun. Notice on the chart above that Earth is not close to the line of the heliocentric conjunction.

From these two planets in alignment, a question may develop about more planets appearing in a line from the sun. Astronomer Jean Meeus (Mathematical Astronomy Morsels, pp. 186-191) addresses the question.  Without reciting his reasons, the answer: “Never!” The dynamics of fast – moving Mercury to slow-moving Pluto (Yes, Pluto is one of the “Classic Nine” planets.), there is never a moment when all nine are in a line stretching from the sun.  He further notes that it’s impossible for even three to be in a line.  Reasonably they can be within a 60° angle of each other, 50° if Pluto is not included.

2020, November 2: Jupiter is 5.0° to the lower right of Saturn, about one hour after sunset. Look toward the south-southwest.

In our sky, the planets are 5.0° apart.  They can be found in the south-southwest about an hour after sunset on November 2.  Saturn is to the upper left of bright Jupiter. The planets are in front of the stars of eastern Sagittarius.  The famous “Teapot” shape is to the lower right of the planets.

The Great Conjunction occurs December 21, 2020.

Continue to watch Jupiter and Saturn, as the Jovian Giant moves in and passes the Ringed Wonder as viewed from our observing spot on Earth.

2021, May 28: Close Venus – Mercury Conjunction

May 28, 2021:  This evening Mercury passes brilliant Venus for the second of three conjunctions during this evening apparition of the second planet from the sun.  Use a binocular about 45 minutes after sunset to see the speedy planet 0.4° to the lower left of Venus.  This is the closest visible conjunction until 2033.

2021, May 24: Planets in a Plane

May 24, 2021: Morning planets Jupiter and Saturn are in the southeast before sunrise.  In the evening sky, brilliant Evening Star Venus, Mercury, and Mars line up along the solar system’s plane.  The bright moon is in the southeast near Zubenelgenubi, “the southern claw.”

2021, May 23: Planet Parade Marches On

May 23, 2021:  Five bright planets parade across the sky.  Jupiter and Saturn are visible before sunrise in the southeastern sky.  The star Fomalhaut is becoming visible below bright Jupiter and near the horizon.   After sundown, Evening Star Venus, Mercury, and Mars are in the western sky.  The bright moon is in the southeastern sky during the nighttime hours.

2021, May 22: Parading Five Planets

May 22, 2021: Five planets parade across the sky.  Jupiter and Saturn are in the southeast before sunrise. Evening Star Venus, Mercury and Mars are in the western sky after sunset.  A bright moon is in the southeastern sky.

2021, May 21: Evening Planet Ballet

May 21, 2021: Three bright planets are dancing in the western sky after sundown.  Evening Star Venus is entering the sky for a months-long residency after its solar conjunction two months ago.  Mercury is heading for a conjunction with Venus after its best evening appearance of the year.  Mars continues its eastward march in Gemini, but time is running out on its appearance as it approaches brighter evening twilight and a conjunction with Venus.

Categories: Astronomy, Sky Watching

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