2021, July 10-18: Watch Jupiter, Saturn Retrograde

July 10-18 2021: Before sunrise Jupiter and Saturn are in the south-southwest. Through a binocular watch them move westward compared to the starry background.

2021, July 15: One hour before sunrise, bright Jupiter and Saturn are in the south-southwest.
Chart Caption – 2021, July 15: One hour before sunrise, bright Jupiter and Saturn are in the south-southwest.

by Jeffrey L. Hunt

Jupiter and Saturn are retrograding in front of their starry backgrounds.  This is an illusion as our planet approaches and passes between the outer planets and the sun.

The normal motion for the planets in the sky is to move eastward compared to the distant stars.

When Earth is between the sun and an outer planet, this is called opposition.  The sun and planet are in opposite directions.  The planet rises in the eastern sky when the sun sets in the western sky.  In the morning, the planet sets in the western sky as the sun rises above the eastern horizon.

Near the time of opposition, the outer planets are near Earth.  They are bright in the sky and are wonderful sights through telescopes.

Saturn is at opposition after midnight (in the Central Time Zone) on August 2.  Jupiter follows 17 days later.

Jupiter and Saturn are well up in the southeastern sky as midnight approaches.  As sunrise approaches, find them in the south-southwest.

Jupiter is the brightest “star” in the morning sky.  Saturn is only dimmer than Jupiter, Mercury (in the east-northeast before sunrise), Arcturus, and Vega.  It’s to the lower right of Jupiter.

The star Fomalhaut is to the lower left of bright Jupiter.

For several mornings, Jupiter seems to move little compared to the stars of Aquarius, Ancha (“the hip,” θ Cap on the chart), Iota Aquarii (ι Aqr), and Sigma Aquarii (σ Aqr).  The planet is moving slowly westward compared to those stars.

Saturn is in front of Capricornus and to the lower right of Theta Capricorni (θ Cap).

2021, July 10-18: Through a binocular, watch Jupiter’s movement each morning as it moves between 38 Aquarii (38 Aqr) and 42 Aquarii (42 Aqr).
Chart Caption – 2021, July 10-18: Through a binocular, watch Jupiter’s movement each morning as it moves between 38 Aquarii (38 Aqr) and 42 Aquarii (42 Aqr).

These planets seem to move westward compared to the stars slowly.  During mid-July, Jupiter moves between two stars, 38 Aquarii (38 Aqr) and 42 Aquarii (42 Aqr).  The chart above shows a view through a binocular for Jupiter from July 10 through July 18.

Each morning note Jupiter’s westward motion compared to those two stars.

2021, July 10-18: Through a binocular, watch Saturn move away from Theta Capricorni (θ Cap) and past 19 Capricorni (19 Cap).
Chart Caption – 2021, July 10-18: Through a binocular, watch Saturn move away from Theta Capricorni (θ Cap) and past 19 Capricorni (19 Cap).

Saturn is retrograding in Capricornus.  Through a binocular watch it move away from Theta Capricorni, passing 19 Capricorni (19 Cap).

Watch the planets each clear morning as they retrograde.

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Saturn (NASA)

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Categories: Astronomy, Sky Watching

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