All posts by Jeffrey L. Hunt

Jeffrey L. Hunt is an educational technologist living in suburban Chicago. When he's not learning about and implementing technology in classes, he's running or looking at the stars.

2020, October 29: Moon, Mars Together Again

The moon and Mars appear together for the second time during the month on October 29, 2020.

Moon and Mars, October 29, 2020
2020, October 29: Two hours after sunset, the moon and Mars appear in the east-southeast. Mars is 4.8° to the upper right of the lunar orb.

by Jeffrey L. Hunt

For the second time during October and two evenings before the rare Halloween Full Moon, the moon and Mars appear together during early evening hours.

Begin looking about two hours after sunset when the pair is about one-third of the way up in the sky in the east-southeast.

At that time, Mars is nearly 30° up in the east-southeast, 4.8° to the upper right of the moon. 

Follow them into the evening sky.  During the night the moon moves farther away from Mars as the lunar orb is moving toward the east compared to Mars and the starry background.  By the next morning, the moon is nearly 8° from Mars in the western sky.

Read more about the planets during October.

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Moon and Mars, September 5, 2020

2020, October 29: Moon, Mars Together Again

The moon and Mars appear together for the second time during the month on October 29, 2020.

Mars at opposition, 2016 and 2018

2020, October: Look For Bright Mars

During October 2020, Mars appears as a very bright star in the eastern evening sky and western morning sky. Mars is closest to Earth on October 6, and at opposition a week later. The moon passes the planet twice, October 3 and October 29.

2020, October 2-3: Moon, Mars Together

On the night of October 2-3, 2020, the moon appears near Mars.

by Jeffrey L. Hunt

Mars appears with the moon on two nights during October 2020, the night of October 2-3 and October 29.

On the evening of October 2-3, look for the moon about two hours after sunset in the eastern sky.  The bright moon is nearly 16 days past its new phase and 98% illuminated. 

Mars and Moon, October 2, 2020
2020, October 2: About two hours after sunset, look for bright Mars 1.7° to the upper left of the bright moon.

Planet is is the bright star that is 1.7° to the upper left of the lunar orb.

As the night unfolds, the pair seems to move westward as Earth rotates.  They appear in the southern sky about 2 a.m. CDT on October 3.  As the new day progresses, the pair is in the western sky.

Moon and Mars, October 3, 2020
2020, October 3: Farther west, the moon – over 26° in altitude in the west-southwest – is 2.8° to the upper left of Mars.

About an hour before sunrise, they are about one-third of the way up in the sky in the west-southwest.  At this time, the moon is 2.8° to the upper left of the Red Planet.

During the night, the moon moves slowly eastward as Mars  inches westward compared to its starfield.

Read more about the planets during October.

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2020, October: Look For Bright Mars

During October 2020, Mars appears as a very bright star in the eastern evening sky and western morning sky. Mars is closest to Earth on October 6, and at opposition a week later.  The moon passes the planet twice, October 2 and October 29.

by Jeffrey L. Hunt

This month the Red Planet is at its closest to Earth and at opposition with the sun.  Mars the overly bright star that appears in the eastern sky during the early evening hours and is visible nearly all night.  As sunrise approaches look for it in the western sky.

Mars is the second brightest “star” following Venus.  The Red Planet’s brightness varies greatly depending on its distance from Earth.

The moon is visible with Mars on the evening of October 2 and morning of October 3.  They appear together again on the evening of October 29, two days before the Halloween Full Moon.

During the month, Mars appears to be moving westward compared to the stars as it nears its closest approach to Earth and its opposition with the sun.  The westward motion is an illusion from our faster moving Earth passing Mars. 

Mars in Pisces, October 2020
2020, October: Mars retrogrades among the dim stars of Pisces as it makes its closest approach and then reaches opposition.

The chart above shows the motion of Mars compared to the dim starfield of Pisces.

Mars’ orbit is elliptical.  This non-circular path takes Mars close to the sun and farther away.  The closest point of Mars to the sun (and any other planet) is known as perihelion; its farthest point from the sun is aphelion.

The perihelion distance from the sun is about 20% closer than the aphelion distance.

Mars revolves around the sun in nearly 687 earth days or 1.88 earth years.  Earth catches, passes, and moves away from Mars every 780 days (on average) – about 26 months.  Sometimes, Mars is near opposition when it is near perihelion.  The same occurs when it is at aphelion.

A perihelic opposition occurred July 27, 2018.  Earth was closest to Mars four days later.  Mars was still moving closer to the sun and had not yet passed its perihelion.

This year, the Martian perihelion occurred August 2.  As Earth approaches Mars, Mars is slowly moving away from the sun.  The closest distance occurs on October 6.

A week later, Mars is opposite the sun in the sky.  Mars rises in the east as the sun sets in the west, appears in the southern sky near midnight, and sets in the west in the morning as the sun rises in the east.

When larger telescopes were developed, observations near oppositions, especially perihelic oppositions, revealed the Martian moons and features on its surface.  Other observations led to misconceptions of Martian canals, cities, and life – and perhaps helped promote science fiction stories of journeys to and from the Red Planet.

For those with telescopes or who want more information about Mars see:

Read more about the planets during October.

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2020, September 25: Morning Planets, Mars and Venus

Mars in Pisces, September 25, 2020
2020, September 25: Mars is nearly between Nu Piscium (ν Psc) and Omicron Piscium (ο Psc) is 0.9° above ν Psc and 2.8° below ο Psc.

Bright Mars and brilliant Venus put on an early morning display.

by Jeffrey L. Hunt

Just before 5 a.m. CDT, bright Mars was high in the southwest.  It is among the dim stars of Pisces. The Red Planet is slowly retrograding – moving westward compared to the starry background.  This illusion occurs when our faster moving planet approaches and passes the slower moving outer planets.

This morning, Mars is nearly between the stars Omicron Piscium (ο Psc on the photo) and Nu Piscium (ν Psc).  The planet is 0.9° above ν Psc and 2.8° below ο Psc.

Mars is closest to Earth on October 6.  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.)

Earth moves between the sun and Mars on October 13.  This is called opposition, because the planets appear on opposite sides of Earth and their place and visible times are opposite of each other.

At opposition, a planet rises at sunset, appears in the south around midnight, and sets in the west

Venus in Leo, September 25, 2020
2020, September 25: Moving eastward in Leo, Venus is 4.8° to the upper left of Omicron Leonis (ο Leo).

At this hour, brilliant Venus is low in the east among the stars of Leo.  An hour later, about 90 minutes before sunrise, Venus is higher in the sky. 

At about 5 a.m. the famous constellation, Orion is in the south-southeast.  Orion’s larger hunting dog, Canis Major, with its bright star  Sirius is low in the southeast.

Among the stars Venus is moving eastward in Leo.  This morning it is 4.8° to the upper left of Omicron Leonis (ο Leo on the photo).  Watch Venus move farther away from ο Leo.  Early next month, Venus passes Regulus, the constellation’s brightest star.

Read more about the planets during September and October.

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Full moon

2020, October 31: Rare Halloween Full Moon

A rare Halloween Full Moon, 76 years in the making, is visible across most of the planet in 2020. This could be called a “Blue Halloween Moon.”

2020, September 25: Saturn and Moon

Saturn, Moon, Jupiter, September 25, 2020
September 25: One hour after sunset, the moon is 3.7° to the lower left of Saturn.

During early evening hours of September 25, the moon appears near Saturn in the southern sky.

by Jeffrey L. Hunt

During the evening hours of September 25, the moon appears 3.7° to the lower left of Saturn.  The gibbous moon is over 70% illuminated.

Jupiter, Saturn, Moon, September 25, 2020.
2020, September 25: The gibbous moon (overexposed in the photo) appears 3.7° to the lower left of Saturn. Jupiter is 7.6° to the lower right of Saturn.

Jupiter is 7.6° to the lower right of Saturn. 

As seen from the sun, Jupiter passes Saturn in a heliocentric conjunction on November 2. This is a prelude to the Great Conjunction on December 21, when Jupiter passes very closely to Saturn. While the planetary pair appears close in the sky, they are hundreds of millions of miles apart in space.

A Great Conjunction occurs every 19.6 years. The last one occurred in 2000. The next Jupiter – Saturn conjunction occurs October 31, 2040, when the two planets rise into the eastern morning sky. The gap is 1.1°. At this year’s conjunction, the two planets appear ten times closer.

While other conjunctions have occurred, this year’s conjunction is the closest Jupiter – Saturn conjunction since 1623.  That year’s conjunction occurred after the invention of the telescope and during very bright evening twilight.  Read our article about whether it was observed.

Read more about the planets during September and October.

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2020, September 24: Jupiter, Moon, Teapot

On September 24, the Moon visits the “Teapot” shape of Sagittarius with the moon nearby.

by Jeffrey L. Hunt

During the early evening of September 24, look in the south for the gibbous moon that is 60% illuminated.  Bright Jupiter is 4.2° to the upper left of the lunar orb. Dimmer Saturn is to Jupiter’s upper left.

Look carefully at the stars to the lower right of the gibbous moon.  They are the main stars of the constellation Sagittarius. The stars resemble a kitchen teapot.  The star Nunki, cataloged as Sigma Sagittarii (σ Sgr), is part of the Teapot’s handle.  Use a binocular, if necessary, to see the shape.

Jupiter is moving eastward compared to the starry background.  Saturn retrogrades, an illusion of moving westward that occurs when the faster moving Earth passes between the sun and the slower moving outer planets.

Next week, Saturn resumes its eastward motion as Jupiter continues to close the gap to the Ringed Wonder toward their Great Conjunction on December 21, 2020. This is the closest conjunction since the Jupiter – Saturn conjunction of 1623.  Great Conjunctions occur every 19.6 years, but this is the closest for nearly 400 years.

Here’s where the moon is on the next evening.

Read more about the planets during September and October.

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Venus and Jupiter, August 18, 2012

The Harvest Moon

The Harvest Moon is the full moon that occurs nearest to the autumnal equinox in the northern hemisphere.

2020, September 22: Equal Night Followed By Equal Light

Venus and Moon, September 14, 2020
2020, September 14: Through a hazy sky, the moon is 5.0° to the lower left of Venus.

The sun crosses the equator at 8:31 a.m. CDT to signal a change in astronomical seasons – the Autumnal Equinox.

by Jeffrey L. Hunt

Autumn begins in the northern hemisphere on September 22, 2020 at 8:31 a.m. CDT.  The sun’s light is most directed toward the equator and for the next six months aimed at the southern hemisphere.

In the northern hemisphere, the sun is lower in the sky and daylight is shorter.

On the day of the equinox, the sun rises east and sets in the west.

The word “equinox” is taken to mean “equal night.”  Daylight and nighttime are nearly equal at 12 hours.

Venus in morning sky, August 12, 2020
Venus in the morning sky.

Being a sky watcher, this writer, considers another date when daylight and darkness are equal.  In the northern hemisphere that occurs in late October.

Normally, we think of two segments of a 24-hour period, daylight and nighttime.  Day is when the sun is shining and night is when it is below the horizon.

Night, though, is made of two parts, twilight and darkness.  Twilight is that period of time – averaging about 90 minutes before sunrise and 90 minutes after sunset at the mid-latitudes – when the sky is illuminated, but it’s not dark.

When the sun is near the horizon, its possible to work outside and find your way around without artificial illumination. Crepuscular creatures wander from the tree line or fly about in the air.   

Crescent Moon, Venus, and Aldebaran, July 17, 2020
2020, July 17: The crescent moon, Brilliant Venus, and Aldebaran shine from the eastern during early morning twilight.

During mid-twilight, the brightest stars are visible. The sky is waxed with cobalt blues, golden yellows, and spectacular oranges.  A crescent moon may be visible just before sunrise or after sunset.  Venus dazzles the eye, and Mercury puts on rare performances.

Sometimes Jupiter plays tag with Venus or Mars is nearby, but the Red Planet is never at its greatest brightness when near Venus.

In the later stages of twilight, the horizon near the sun’s last rays continues to hang on to the final shreds of the sun’s glory.

Then darkness falls hard. The sky is ablaze with the night’s stars. The nocturnal animals prowl and the sky watchers gaze through their telescopes.

So, this writer looks beyond the equinox to the “equal light” days of late October when daylight and darkness are equal, at about 10.5 hours.

Take a look for the morning planets Venus and Mars before sunrise.  Jupiter and Saturn are in the south during the early evening.  Mars joins them before midnight.  Here is a summary of what’s happening with the planets during September.

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2020, September 18: Bright Morning Planets, Stars On Display

Mars in Pisces, September 18, 2020
2020, September 18: Mars, now slowly retrograding in dim Pisces, is 1.9° to the upper left of Nu Piscium (ν Psc) and 2.5° to the lower left of Omicron Piscium (ο Psc).

A clear sky this morning allowed brilliant Morning Star Venus and bright Mars to put on a planetary display before sunrise.

by Jeffrey L. Hunt

A north breeze that cleared smoke from the western wildfires revealed bright planets and bright stars.

At about 4 a.m. CDT, bright Mars was high in the south-southwest.  It is among the dim stars of Pisces. The Red Planet is slowly retrograding – moving westward compared to the starry background.  This illusion occurs when our faster moving planet approaches and passes the slower moving outer planets.

Mars is closest to Earth on October 6.  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.)

Earth moves between the sun and Mars on October 13.  This is called opposition, because the planets appear on opposite sides of Earth and their place and visible times are opposite of each other.

At opposition, a planet rises at sunset, appears in the south around midnight, and sets in the west as the sun rises in the east.  Mars appears at opposition about every 26 months.

On the photo above, Mars appears 1.9° to the upper left of Nu Piscium (ν Psc on the photo) and 2.5° to the lower left of Omicron Piscium (ο Psc). 

Venus with bright stars, September 18, 2020
2020, September 18: Brilliant Morning Star Venus appears with Sirius, Procyon, Castor, Pollux, Betelgeuse and Rigel.

At this hour, brilliant Venus is low in the east.  An hour later, about 90 minutes before sunrise, the planet is higher in the sky. 

At this time Venus appears with other bright stars.  The night’s brightest star, Sirius, is low in the southeast. About a month ago, the star made its first appearance in the morning sky this year.

The famous constellation Orion – with its bright stars Betelgeuse and Rigel – are to the upper right of the Dog Star.

With a binocular the Orion Nebula, a stellar nursery – is visible as a hazy cloud.  The Little Dog Star – Procyon – is nearby.  The Gemini Twins – Castor and Pollux appear above Venus

Venus in Cancer, September 18, 2020
2020, September 18: Venus is in the east before sunrise. It is 1.4° to the lower left of Omicron Cancri (ο Cnc).

Among the stars Venus is moving eastward in the very dim starfield of Cancer.  This morning it is 1.4° to the lower left of Omicron Cancri (ο Cnc on the photo).  Watch Venus move farther away from ο Cnc.

Here is a daily summary about the planets during September.

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2020, September 17: Jupiter, Saturn, International Space Station

The International Space Station passes Jupiter and Saturn, September 17, 2020
2020, September 17: The International Space Station passes Jupiter and Saturn during a 10-second time exposure. The planets are 8.0° apart.

After the sky cleared today, the International Space Station made a bright pass across the mid-northern latitude states this evening near Jupiter and Saturn in the sky.  The ISS was brighter than the planet Jupiter.

by Jeffrey L. Hunt

The International Space Station passes Jupiter and Saturn this evening as seen across the Midwest.  A clearing sky permitted viewing this evening.  At its brightest, the ISS was easily brighter than Jupiter.

As for the planets, Jupiter is 8.0° to the right of Saturn.  Jupiter passes Saturn in a Great Conjunction on December 21, 2020. This is the closest conjunction since the Jupiter – Saturn conjunction of 1623.  Great Conjunctions occur every 19.6 years, but this is the closest for nearly 400 years.

Before Jupiter passes Saturn in our sky, Jupiter edges past Saturn as viewed on the solar system’s scale in what is known as a heliocentric conjunction.  This occurs on November 2.

Continue to look for Jupiter and Saturn each evening.  During the next several weeks, watch Jupiter close the gap to Saturn.

Here is a daily summary about the planets during September.

Recent Articles

2020, September 13: Bright Jupiter Begins to Close on Saturn

Jupiter and Saturn in Sagittarius, September 13, 2020
2020, September 13: Saturn is 8.1° to the left of Jupiter. In the starfield, Jupiter is 2.1° to the lower left of Pi Sagittarii (π Sgr) and 2.9° to the lower right of 50 Sagittarii (50 Sgr). Saturn is 1.7° to the lower left of 56 Sagittarii (56 Sgr).


Jupiter’s retrograde ends and the Giant Planet begins to close on Saturn for the Great Conjunction of 2020.

by Jeffrey L. Hunt

Bright Jupiter and Saturn are in the south as the sky darkens from early evening twilight.

Jupiter is now moving eastward compared to the starry background, while Saturn retrogrades – moves westward compared to the stars – until month’s end.

This evening Jupiter is to the lower left of Pi Sagittarii (π Sgr on the photo above) and to the lower right of 50 Sagittarii (50 Sgr). 

Saturn is 8.1° to the left of bright Jupiter.  It is 1.7° to the lower left of 56 Sagittarii (56 Sgr).

The gap between Jupiter and Saturn begins to close until the Great Conjunction of 2020, when Jupiter seems to pass very close to Saturn in the evening sky.  This is the closest conjunction since the Jupiter – Saturn conjunction of 1623.  Great Conjunctions occur every 19.6 years, but this is the closest for nearly 400 years.

Before Jupiter passes Saturn in our sky, Jupiter edges past Saturn as viewed on the solar system’s scale in what is known as a heliocentric conjunction.  This occurs on November 2.

Continue to look for Jupiter and Saturn each evening.  During the next several weeks, watch Jupiter close the gap to Saturn.

Here is a daily summary about the planets during September.

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