2020, August 21: Mars Gleams in Morning Sky

Bright Mars shines from the southern sky before sunrise.

by Jeffrey L. Hunt

Mars is the bright “star” in the southern sky before sunrise.  It complements the brilliant Venus that shines in the east.  Mars has been part morning planet parade that has included Saturn and Jupiter.

Mars is approaching its opposition (October 13) and its closest approach to Earth (October 6). 

At opposition, the Red Planet rises in the east as the sun sets in the west.  The planet is in the southern sky around midnight, and it sets in the west as the sun rises in the east.  The sun and Mars are in opposite directions in the sky.

In history, astronomers have been attracted to the nearly biennial Martian opposition.  At these times the planet presents itself for excellent telescopic inspection.  The planet’s moons were first observed during the opposition of 1877.  At the same opposition Giovanni Schiaparelli sketched Martian features, including “canali.”   Robot spacecraft are launched toward Mars near opposition because the planets are close together, travel times are relatively short, and minimal rocket fuel is needed.  NASA’s Perseverance rover was launched July 30.  The craft’s planned arrival is mid-February 2021.

Because the Martian planetary orbit is not a perfect circle, the planet is closest to Earth a week before its opposition, shining brightly all night.  Currently, the planet rises at about 10 p.m. and is high enough to be easily seen about an hour later.

Early in September, Mars begins to retrograde – move westward compared to the starry background.  This is an illusion as our faster moving Earth catches and passes Mars and the other planets.  Every object in the solar system – except the sun – appears to retrograde from the combined orbital patterns of Earth and the other bodies.

Mars is currently moving eastward compared to the dim stars of Pisces.  It is 0.5° to the upper right of Nu Piscium (ν Psc on the photo) and 2.3° to the left of Mu Piscium (μ Psc).

As an aside, the separation between Mars and ν Psc is about the diameter of the full moon.  If the moon were in the sky this morning, it could appear between the planet and the star, as seen in the sky.

This evening, locate Jupiter and Saturn in the southeastern sky after sunset.

Here is a daily summary about the planets during August.