2020, August 12: Mars, A Planetary Dance


Mars begins its planetary dance as it nears its closest approach to Earth and its opposition with the sun.

by Jeffrey L. Hunt

Bright Mars shines from the south-southeastern sky during the early morning hours.  It is moving eastward in a dim starfield of Pisces.

Within a month, Mars begins to retrograde. This is an illusion as our planet approaches and passes the Red Planet and all other planets, minor planets, and comets that are farther away from the sun than our home planet.

As Earth approaches Mars, the Red Planet becomes brighter, but not much larger in appearance to the human eye.  While it can double in its apparent size through a telescope, the increase is imperceptible to the human eye (unlike what is shown in the social media memes.)

Mars rises in the east before 11 p.m. and shines high in the southern sky before sunrise.  As it rises in the evening, Jupiter and Saturn are in the south.

Four planets – Jupiter, Saturn, Mars, and Venus – are visible around 3 a.m., shortly after Venus rises, but clear horizons are necessary to see the planetary quartet together.  And the window to see all four in the morning sky is closed on August 25.

The charts in this article show the entire retrograde path of Mars along with the view of the two planets as they revolve around the sun.

On the photo above, Mars is 3.1° to the upper left of 89 Piscium (89 Psc) and 1.1° below Mu Piscium (μ Psc).  It is moving eastward in a path that is taking it toward and above, Nu Piscium (ν Psc).

Mars seems to stop moving forward and begins to retrograde on September 9, below Omicron Piscium (ο Psc).  The planet then moves westward, passing ν Psc again. Earth and Mars are closest on October 6, 2020, when the Red Planet appears near μ Psc.

Earth passes between the sun and Mars on October 13, This is known as opposition.  The planet rises in the east as the sun sets in the west.  As Earth rotates, the planet appears farther west during the night, in the south around midnight, and sets in the west at sunrise.

At opposition, Mars is a few degrees to the right of μ Psc.

Mars continues to retrograde until November 13, after it passes below 80 Piscium (80 Psc). It does not move as far west as Delta Piscium (δ Psc).  As it moves eastward against the starry background, it passes below Epsilon Piscium (ε Psc) and then Pi Piscium (π Psc), as the year ends.

Use a binocular to spot the dim stars in the near Mars and watch its planetary dance with the stars.

Venus appears in the eastern morning sky to the lower left of the Red Planet.

The first sightings of Sirius by the unaided eye occur this week about 45 minutes before sunrise.

Here is a daily summary about the planets during August.


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