On the night of September 5/6, the gibbous moon appears to guide the bright planet Mars.
Update: Photo from September 5, 2020.
by Jeffrey L. Hunt
On the night of September 5 – September 6, the gibbous moon appears near Mars, a very bright planet in the southern sky before sunrise. Currently, Mars is the fourth brightest “star” in the sky. Only, the moon, Venus, and Jupiter are brighter.
As Earth approaches Mars, the Red Planet brightens – during the next six weeks – although it is not much larger in appearance to the human eye. Even with a closest approach pending, the planet only resembles an overly bright star. 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.)
On the evening of September 5 and morning of September 6, the bright gibbous moon is near the Red Planet. Here’s what to look for on the night before and after the grouping:
- September 5: One hour before sunrise, the bright gibbous moon is over 40° up in the southwest. The moon is over 91% illuminated. Mars is 9.6° to the upper left of the lunar orb. The separation is about the distance across your fist at arm’s length. In the evening, about three hours after sunset (10:15 p.m. CDT, in Chicago), the moon – about 86% illuminated – is to the lower right of Mars, about 0.8° away. That’s about the distance across two fingertips at arm’s length. Find them in the east. On these evenings find bright Jupiter and Saturn – to Jupiter’s upper left – in the south-southwest sky.
Update: Photo from September 6, 2020.
- September 6: One hour before sunrise, the moon is over halfway up in the southwest. Mars is 2.3° to the lower right of the lunar orb. Three hours after sunset in the eastern sky, bright Mars is over 11° to the upper right of the moon that is 79% illuminated. The moon is near the eastern horizon.
- September 7: One hour before sunrise, the bright moon – 77% illuminated – is less than 60° in altitude in the south-southwest. Mars is about 15° to the lower right of the moon.
Each night, the moon is farther east of Mars and it begins to approach Venus in the east in the morning sky. Look for the crescent moon and Venus on September 14.
Here is a daily summary about the planets during September.
July 7, 2021: In five evenings, Venus passes Mars for the first conjunction in a triple conjunction that carries into 2022. Look for them low in the west-northwest after sunset.
July 2021: Elusive Mercury appears in the morning sky in the east-northeast during morning twilight. The best mornings to see Mercury are July 7 and July 8, when the moon is nearby.
July 6, 2021: In less than a week, brilliant Venus passes Mars in the west-northwestern sky after sunset. This evening the two planets are 3.8° apart. Venus is over 18° to the lower right of the star Regulus.
July 1 – July 7, 2021, the waning crescent appears in the eastern sky. Early in the viewing period, the moon is among the dim stars of Pisces. As the week progresses, the moon wanes and moves farther eastward, appearing near Taurus.
July 5, 2021: Our planet Earth reaches its farthest point in its yearly trek around the sun. Our seasons are not related to Earth’s distance from the sun. Coincidentally, the moon is at its farthest point from Earth today.