2017: October 5: Venus-Mars Conjunction


Update:  On the morning of October 5, 2017, Conjunction Morning!

The Venus-Mars Conjunction of November 3, 2015.


The Venus-Mars Encounter, February 3, 2017.  (There was no conjunction.  Venus approached Mars and then moved away.  This was the closest approach)

Mars and Venus were last in conjunction on November 3, 2015 when they were about 3/4 degree apart.  As with the last conjunction the 2017 conjunction occurs in a sky full of planets as noted here.  Also note that these conjunctions occur farther east along the solar system’s (ecliptic) plane.

As Venus heads toward its solar superior conjunction, it passes Mars on the morning of October 5.  Conjunctions of Venus and the visible outer planets (Mars. Jupiter, and Saturn) can occur when Venus is within 47 degrees of the sun, its greatest angular separation from the sun.  Because Mars is small and its brightness greatly varies depending on its distance from Earth, Mars is dim when it appears near Venus. (Note this in the two images at the top of this article.)  A Venus-Mars conjunction cannot occur when Mars is near opposition and at its brightest.  For more about the Mars appearance and its opposition, see 2017-2019: Mars Observing Year with a Perihelic Opposition, July 27, 2018  and  2018:  Mars Perihelic Opposition.

Mars’ separation from the sun has grown to 23 degrees after its solar conjunction on July 27, 2017.  Earth is slowly catching Mars, yet opposition is months away.  From this scale drawing notice that Venus’ orbit is closer to Earth than Mars.

On conjunction morning the separation of the pair is about one-fourth of a degree.  This would be spectacular conjunction if Mars were brighter.  The planets are close for a few mornings before and after this close passing.

Future Venus-Mars Conjunctions

The next six conjunctions are summarized below:




August 24, 2019 0.31 degree (d) Venus and Mars are 3 degrees east of the sun, setting just minutes after sunset.  This conjunction is not visible.
July 13, 2021 0.49 d The pair is in the evening sky, setting about 90 minutes after sunset.  Look low in the western sky.  Regulus is about 10 degrees to the upper left of the Venus and a four-day-old waxing crescent moon is 20 degrees to upper left of Venus.  Just 2 nights before the closest conjunction look for the moon near Venus (6 degrees)
February 13, 2022 6.58 d This widely spaced conjunction occurs in the morning with the pair rising 2.5 hours before the sun.  Feb 13 is the date the of the conjunction, although the pair is closest on February 19, 5.8 degrees.  (Conjunctions are defined in at least 3 ways.)
March 12, 2022 3.99 d This conjunction is a continuation of the close approach that starts in early 2022 in the morning sky.  The first conjunction is noted above and the planets continue to be close together for many mornings.  The pair is close again on March 16, 3.8 degrees
February 22, 2024 0.63 d Venus and Mars rise about 35 minutes before the sun during bright twilight.  To see this conjunction, optical assistance, binoculars or telescope, is needed.
January 8, 2026 0.17 d This conjunction is closer than the 2017 conjunction, but the planets are 1 degree from the sun, hidden in the sun’s brilliance.

From this list, the 2021 conjunction and the widely spaced conjunctions in 2022, with an extended period when the two planets appear together, are the best times to see Venus and Mars close together during the next decade.


2017, July 14: Venus and Aldebaran

Brilliant Venus shines low in the eastern sky this morning at 4:15 a.m. CDT with Aldebaran about 4 degrees away.  Click the image to see the stars near Aldebaran that comprise the Hyades star cluster.  The Pleiades cluster appears above Venus and Aldebaran.

For more information about sky watching events:

2017, November 13: An Epoch Venus-Jupiter Conjunction


Update:  Venus and Jupiter, Conjunction morning, November 13, 2018

The Epoch Venus-Jupiter Conjunction, August 27, 2016

An Epoch Conjunction

A Venus-Jupiter Epoch (close) conjunction occurs 443 days after the last conjunction of these two bright planets shown in the image above.  This conjunction occurs just before sunrise on the morning of November 13, 2017 when the two planets are about 0.3 degrees apart. This article outlines the circumstances of conjunctions between Venus and Jupiter, the events of this conjunction, and concludes with a list of future Venus-Jupiter conjunctions.

Conjunctions of the bright planets occur when they appear to move past each other in the sky.  Sometimes they seem to nearly meet, although they are millions of miles apart.  A Venus-Jupiter conjunction occurs between 34 days and 449 days, depending on the relative positions of the three planets (this includes Earth).  Venus revolves around the sun once in about 225 days.  Because our planet is moving, Venus catches up to and passes by Earth every 584 days.  Jupiter is a slower moving participant in this celestial waltz as it revolves around the sun once in nearly 12 years.

Venus-Jupiter conjunctions occur somewhat frequently; the close ones of are great visual interest, because to the unaided eye, the planets appear to merge together.  While not a “once-in-a-lifetime”event, these close conjunctions are infrequent enough to attract the attention of even the casual sky watchers.  Robert C. Victor, former staff astronomer at Abrams Planetarium, calls these close conjunctions “epoch conjunctions.”

Venus is always visible near the sun as it is closer to the sun than Earth.  From our planet it never appears more than about 47 degrees from the sun.  When it is east of the sun, it appears in the western sky just after sunset.  When it is west of the sun, it appears in the eastern sky, just before sunrise.

Jupiter’s movement in the sky largely follows the earth’s revolution around the sun and mostly reflects the annual westward advancement of the starry background.  Jupiter first makes a morning appearance in the eastern sky, just past conjunction when Jupiter is on the far side of its orbit behind the sun.  Each week it appears higher in the sky and farther west at the same time each morning.  Several months later, it appears in the western sky just before sunrise from this slow westward celestial migration.  At this time it is at opposition with Earth between the sun and Jupiter; they are on opposite sides of our sky.  At this time, Jupiter rises a sunset, appears in the south at midnight and sets at sunrise — appearing in between at other times during the night.  Jupiter continues to rise earlier each week, eventually appearing in the south at sunset.  As Jupiter heads for conjunction (behind the sun) it appears in the western sky at sunset, eventually setting with the sun.  This entire cycle takes 399 days.

Because Venus’ orbit is inside Earth’s orbit, Venus never appears more than 47 degrees from the sun, the Venus-Jupiter conjunction appears within region of the sky when Jupiter is near conjunction.  Additionally, if the Venus-Jupiter conjunction occurs too close to the sun, the planets are hidden in the sun’s brilliant glare.  In recent times, 75% of the conjunctions occur when Venus and Jupiter are very close to the sun.

The Conjunction

From the above chart notice that Venus is a brilliant Morning star for most of 2017.  During the autumn it rises closer to sunrise than it did in summer. It is heading toward its superior conjunction with the sun on January 9, 2018.  Jupiter reaches its solar conjunction on October 26, 2017.  It is behind the bright sun.  Jupiter slowly emerges into twilight and then begins rising before morning twilight begins.  The November 13th conjunction occurs during twilight.  It is not impossible to view.  Two factors are important:  Having a clear eastern horizon and viewing the pair before the sky grows too bright.  The pair is only 14 degrees west of the sun and 5 degrees above the horizon, making the view a little tricky.

Unlike other recent Venus-Jupiter conjunctions, showing events leading up to the conjunction are limited by Jupiter’s solar conjunction that occurs only 18 days before this epoch meeting.  Further Venus is headed for its solar superior conjunction and rapidly plunging into the solar glare.  Our lead-up and follow-up descriptions are limited by the sun’s glare.

The views on the charts below are 40 minutes before sunrise, 6 a.m. CST in the Chicago, Illinois region.  Check your location for the sunrise time and look for the planetary pair 40 minutes before sunrise.

Brilliant Venus and bright Jupiter shine from low in the east-southeastern sky.  The pair is only about 5 degrees above the horizon. Venus is twice as bright as Jupiter.  On the morning before the conjunction, November 12, Venus is slightly less than one degree above Jupiter.   Spica is nearly 13 degrees to the upper right of  Venus; Mars is 23 degrees; and the moon is 55 degrees above Venus.

This chart shows the relative sizes of the planet orbits for the conjunction.   The sizes of the planets have been exaggerated to see them.  The angle the planets make with the sun is only 14 degrees making them appear low in the eastern sky.  At the time of the conjunction, Jupiter is nearly 4 times farther away than Venus.

On conjunction morning, the pair is still very low in the east-southeastern sky.  They are about 1/3 of a degree apart!    Spica is 13.5 degrees to the upper right of Venus; Mars is nearly 24 degrees above Venus; and the moon is 43 degrees above Venus.

Through a telescope, Venus and Jupiter appear in the same field of view.  The Galilean Satellites, the four large moons, line up with Jupiter’s cloud bands.  Two appear  above Jupiter and two below.  Depending on the optical configuration of the telescope, Venus is visible to the side of Jupiter.

On the morning following the conjunction, Venus and Jupiter are over a degree apart.  Spica is 14.5 degrees to the upper right of Venus; Mars is 24 degrees above the bright planet; and the moon is 31 degrees above Venus.  The moon is 11 degrees above Mars.


Update:  Venus 1.4 degrees to the lower left of Jupiter:  November 14, 2017.

For more about the appearances of Venus and Mars, see these articles:

Upcoming Venus-Jupiter Conjunctions

The table below shows the next 6 Venus-Jupiter conjunctions.  The February 2025 event rival this conjunction in separation.   Following the conjunctions mentioned on this list, a close conjunction (28′) occurs on August 23, 2038 followed by a closer conjunction occurs on November 2, 2039 (13′).  Other more widely spaced Venus-Jupiter conjunctions (30′ to 2 degrees) occur in the interim.

Conjunction Dates Separation Location Visibility
January 22, 2019

2 degrees, 24 minutes

Morning (east)

The planets in this widely spaced conjunction are far apart visually, but easily seen as they rise about 3 hours before sunrise and appear in low in the southeastern sky as morning twilight begins.
November 24, 2019

1 degree, 28 minutes

Evening (west)

The planets in this widely spaced conjunction are nearly 3 full moon diameters apart.  They are visible low in the southwestern sky during twilight and early evening, setting about 1 hour, 35 minutes after sunset.
February 11, 2021



This pairing is very difficult to see in the eastern sky as the planets rise in bright twilight just 25 minutes before sunrise.
April 30, 2022



The planets rise in the eastern sky about 90 minutes before sunrise.  In separation, this rivals the June 2015 conjunction, although it is lower in the sky.
March 1, 2023



This conjunction rivals the June 2015 pairing, with the planets high in the west after sunset, setting 2 hours, 30 minutes after the sun.
May 23, 2024 15’ Morning This pairing is impossible for casual observers to see as it occurs when the planets are nearly behind the sun hidden in the solar glare.

2018: Mars Perihelic Opposition


Figure 1: With opposition on July 27, Mars completes a perihelic opposition on July 27, 2018.

Companion Articles:


After its solar conjunction in late July 2017, Mars begins a 768-day cycle during which it reaches opposition; that is, Earth is between the sun and the Red Planet.  The opposition occurs July 27, 2018.

This one is special as it occurs when Mars is near its closest point to the sun: perihelion.  And so this opposition is known as a “perihelic opposition.”  Such oppositions occur every 15 years or 17 years. Oppositions occur about every 25 months, but the ones when Mars is near perihelion are of special interest.

This article explains the entire apparition of Mars.

Here we describe part of the appearance, near opposition.  Mars orbit is not a perfect circle; it’s an ellipse.  If Earth passes Mars when it is near perihelion, terrestrial telescopes capture exquisite pictures of this planet.  Before the 2018 opposition, the 2003 opposition occurred when Mars was very close to perihelion.  Other very close perihelic oppositions occurred:

  • August 18, 1845
  • August 23, 1924
  • August 10, 1971
    See this source for a listing of other Mars oppositions.

Figure 2:NASA Image from the 2003                       perihelic opposition

Phobos and Deimos, the moons of Mars, were first observed by Asaph Hall near the time of the perihelic opposition in 1877.  At opposition the planet is in the sky all night as it rises in the east at sunset and sets in the west and sunrise.  It is near its closest to Earth and is at its best observing.

With robot spacecraft roving on the martian surface and revolving above the planet, perihelic oppositions are not as exciting as those in recent history; yet, to watch the planet grow in brightness and appear as a small ocher orb in a telescope is an exciting opportunity.

Events Around Opposition

Because Mars is near our planet, it moves around the sun at about half the speed of Earth.  Our planet catches and moves past Mars in a little over two years.  So compared to most other observations of the planets, the intervals between oppositions seem long.

Figure 3:   Orbital Chart. This chart shows the overhead view of Earth and Mars during 2018

The two charts (Figure 1 and Figure 3) show two different views of the same events.  The former chart shows the view of what we see from our viewpoint on Earth.  The latter shows the orbital paths of the two planets as viewed from above the solar system.  (Click the charts to see them larger.)

Here are the events as noted on the charts:

  • April 27, 2018:  Mars is over 81 million miles from Earth.  It is brighter than any other “star” in the region, except for Jupiter which is 60 degrees to the west of Mars.  Mars rises in the southeast at about 1:30 a.m.
  • Between these two dates, Mars appears to move eastward compared to the starry background.  In June Mars appears to slow down its eastward motion.
  • June 26, 2018:  Mars stops moving eastward and begins to slowly move westward compared to the starry background.  It is 44 million miles away and has grown five times in brightness. The planet rises at about 11 p.m. It is important to note the Mars appears as a star and during this opposition, it cannot be seen as a planetary globe with the unassisted eye.  A telescope is needed  to see its shape.
  • July 27, 2018:  Mars is at opposition.  In one month it nearly doubles in brightness.  It is nearly as bright as Jupiter, yet appears starlike without a telescope.  It is 35.8 million miles away.  It rises in the southeast at sunset and sets in the southwest at sunrise.  It is highest in the south around midnight.  This is the best time to view the planet through a telescope.
  • July 31, 2018: Mars is closest to Earth (closest approach).  It is 35.7 million miles away.  Mars is not necessarily closest at opposition because of its elliptical orbit.  Mars is still moving toward perihelion gradually getting closer to the sun each day.
  • August 27, 2018:  Mars stops retrograding.  It is 41 million miles away.  It is still bright but its intensity is noticeably diminished.  Earth is now pulling away from Mars.  Mars begins moving eastward again compared to the starry background
  • September 15, 2018:  Mars is a its solar perihelion, 47 million miles away from Earth.
  • October 13, 2018:  (The last date charted.)  Mars is 62 million miles away from Earth and distinctly dimmer than it was at opposition.  As Earth moves away from Mars, the Red Planet appears to pick up speed as it moves eastward.

One of the biggest challenges of our ancestors was to explain the retrograde motion of Mars (Figure 1), Jupiter, and Saturn.  From a sun-centered explanation of the solar system, these outer planets seem to stop and backup as a faster moving Earth catches and passes them.  From Figure 3, note that the planets do not stop at any time in their orbital motions.

Date Distance
(Million Miles, rounded)

Brightness (m)

Brightness Change
(From Previous Date)
April 27, 2018        81        -0.3
June 26, 2018        44        -2.08 5.2 x brighter
July 27, 2018        35.8        -2.78 1.9 x brighter
July 31, 2018        35.7        -2.78 No Change
August 27, 2018        41        -2.2 2 x dimmer
September 15, 2018        47        -1.7 1.6 x dimmer
October 13, 2018        62        -1.0 1.3 x dimmer

Table 1:  Some properties of Mars, 2018

The table above summarizes the preceding text .  The magnitude column shows the brightness of Mars on a numerical scale.  Smaller numbers indicate that the planet is brighter.  The scale becomes more negative numerically for brighter objects.  (The sun’s magnitude is -26.5.  After all it is so bright that it causes daytime.)  From April 27 through July 27, Mars increases in brightness 2.48 magnitudes.  To the eye that corresponds to a 10 times increase in brightness. Each step on the magnitude scale is about a 2.5 times change in brightness.  In comparison here are magnitudes of some other bright stars:

  • Sirius, -1.44 (the brightest star in the night sky)
  • Arcturus, -0.05
  • Betelgeuse, 0.45
  • Aldebaran, 0.87

An exciting viewing opportunity occurs during the next year.  With this opposition occurring in July 2018, it is easily observed.  The next martian opposition is October 13, 2020 with the next perihelic opposition September 15, 2035 at a distance of 35.4 million miles from us.  Happy observing!