2016: Jupiter During May

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Jupiter shines brightly from the southern skies during the early evening hours of May 2016. It appears among the stars of Leo with its bright star Regulus that shines about 13 degrees to the upper right of Jupiter.  The planet is about 25 times brighter than this star. At mid-month the moon passes through the region.  Here are the events of the three evenings.

May 13:  The First Quarter Moon appears 3.5 degrees to the lower right of the star Regulus.

May 14:  The moon appears 4 degrees to the lower right of Jupiter.

May 15.  The moon appears 9 degrees to the lower left of Jupiter.

2016, August 27: A Venus-Jupiter Epoch Conjunction

The June 30, 2015, Venus-Jupiter Conjunction.  The 2016 conjunction is closer.

An Epoch Conjunction

Just 424 days after the last Epoch Conjunction, Venus and Jupiter pass again in the western, evening sky on August 27, 2016, shortly after sunset.  The image above shows the two planets during were about one-third of a degree in separation during the 2015 conjunction.  The 2016 conjunction is three times closer.  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.

See this article for more as Venus as an Evening Star during 2016-2017.

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 45 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 45 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.

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During the August 2016 conjunction, Venus is emerging from behind the sun (superior conjunction).  Venus is only 22 degrees from the sun, setting 56 minutes after the sun, and before Nautical Twilight.  Jupiter is nearing its solar conjunction which is caused more by the earth’s revolution than Jupiter’s orbital movement.  The two planets are about 450 million miles apart, although they appear about 7′ (7 minutes= 0.10 degrees, much less than a full moon diameter) apart.

The Conjunction

Here are the events leading up to the conjunction.

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On August 1, Venus is low in the western sky.  Find a clear horizon to see it.  Bright Jupiter is 26 degrees to the upper right of Venus.  Mercury is  about 8 degrees to the upper right of Venus.

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While not a good appearance, the evening of August 4, 2016, presents another opportunity to view all five naked eye planets simultaneously.  Locate a clear horizon looking west.  Venus stands about 3 degrees above the western horizon.  While it is bright in the twilight, binoculars may be needed to first locate it.  A thin crescent moon appears 10 degrees to the upper left of Venus, with Mercury  2 degrees to the upper right of the Moon.  Jupiter is higher to the upper left of the moon (14 degrees).  Saturn and Mars in the southern sky, near the star Antares.

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On August 6, the separation between Venus and Jupiter decreases to 21.5 degrees with the moon 10 degrees to the upper left of Jupiter.

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On August 15, Mercury is rapidly disappearing from the sky.  Tonight Venus and Jupiter are 12 degrees apart.

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By August 20, the Venus-Jupiter distance is 7.5 degrees.

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On August 24, the pair is 3 degrees apart.

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Two evenings later and the evening before the conjunction, the Venus-Jupiter distance is 54′ apart.

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August 27, 2016 is conjunction evening when the two planets are 7 arc minutes apart!

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In a telescope at about 80 power, Jupiter and its four largest moons are visible along with Venus.  The view through your telescope may be inverted or backwards left to right, depending on the optical design.  The four largest moons are in a plane that is along the cloud bands of the planet.

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On the evening following the conjunction, the planets are 1 degree apart. with Jupiter to the lower right of Venus.

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On August 30, the planets have separated to 3 degrees.

The planes continue to separate and Jupiter disappears into the sun’s glare heading for solar conjunction (September 26, 2016).

Upcoming Venus-Jupiter Conjunctions

The table below shows the next 7 close Venus-Jupiter conjunctions.  The November 2017 conjunction and 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
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November 13, 2017 20’ Morning(east) During this conjunction the planets rise in the east-southeast about 75 minutes  before sunrise.  In separation, it rivals the June 2015 conjunction, but it appears low in the sky.
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.
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.
February 11, 2021 26’ Morning 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 29’ Morning 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 32’ Evening 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.

2016, April 17: Jupiter and Moon

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That bright star near the moon this evening is Jupiter. The accompanying chart shows the pair high in the southeastern sky tonight at 9 p.m. CDT. Jupiter and the moon are 2.5 degrees apart. The star Regulus is nearby.

Jupiter and the moon appear together throughout the evening and night as our planet rotates, and they appear to move westward.  In the Chicago area, the moon sets in the west at about 4:30 a.m. CDT.

While Jupiter and the moon appear close together, Jupiter is nearly 1800 farther away than the moon, yet Regulus is over 3.5 million times more distant than Jupiter.

Did you see Mercury this evening?  For the next several evenings, look low in the west-northwest about an hour after sunset.  Here’s our view from last night.

2016: Jupiter at Opposition, March 8

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Jupiter is at opposition today (March 8).  It rises in the east at sunset; appears in the south at midnight; and shines from the west at sunrise.  Today our planet is between Jupiter and the sun, so they are on opposite sides of our planet and appear in opposite positions in the sky — opposition.  Jupiter is closest (409 million miles) to us and at its brightest.  It shines in front of the stars of Leo with its brightest stars Regulus and Denebola.

Jupiter takes nearly 12 years to revolve around the sun once.  In this Jovian year, Jupiter slowly creeps eastward among the stars, taking the entire Jupiter year to travel along the ecliptic.

Tonight Jupiter appears nearly 90 degrees from Saturn, which completes one solar orbit every 29.5 years.  Jupiter is slowly catching Saturn which rises about 12:30 a.m.

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On December 21, 2020, Jupiter passes Saturn in a spectacular conjunction.  The planets appear about 0.1 degree apart! The following  Great Conjunction of Jupiter and Saturn is Nov 5, 2040.  The planets are separated by nearly 1.5 degrees  on this conjunction.

So keep track of the two planets and watch Jupiter slowly catch Saturn.

2016-2017: Venus, Evening Star

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During its evening appearance in 2015, Venus appeared near bright stars and planets.

After a spectacular appearance in the morning sky, brilliant Venus moves into the evening sky during the summer of 2016.  Every 585 days it appears in the evening sky.

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On June 8, 2016, Venus passes on the far side of the sun in its orbit (superior conjunction) and slowly moves into the evening sky.  At superior conjunction the planet rises with the sun, lies in the south at noon, and sets with the sun.  Because of this Venus us invisible to us. By early July, it moves from the brilliant glare of the sun, setting in the northwestern sky about 45 minutes after sunset.  As the summer progresses, it rises higher in the sky each evening, setting later each night. Times are on the configuration diagrams to show the times of noon and midnight.  Additionally the morning side of the sky is distinguished from the evening side with the evening planets.  These times are referenced from our planet.  Notice that we never see Venus in the midnight sky.  (The midnight arrow never points at or goes through Venus.)

Challenge View: 5 Planets

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As Venus emerges from the sun, Mercury reaches its greatest angular separation from the sun.  While not a good appearance, the evening of August 4, 2016, presents another opportunity to view all five naked eye planets simultaneously.  Locate a clear horizon looking west.  Venus stands about 3 degrees above the western horizon.  While it is bright in the twilight, binoculars may be needed to first locate it.  A thin crescent moon appears 10 degrees to the upper left of Venus, with Mercury  2 degrees to the upper right of the Moon.  Jupiter is higher to the upper left of the moon (14 degrees).  Saturn and Mars in the southern sky, near the star Antares.

Venus:  Evening Star, the Chart

This chart shows the setting times of Venus ,the moon, planets, and stars compared to sunset during the appearance of Venus in the evening sky during 2016-2017. Chart calculated from data by the U.S. Naval Observatory.

This chart shows the setting time of Venus compared to the sun during its evening appearance.  The setting time differences of other planets and bright stars are included.  For a detail discussion of this chart, see this article.

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On the evening of August 27, Venus moves past Jupiter. This is another Epoch Venus-Jupiter Conjunction.  On this evening the pair is only  7′ (seven arc minutes) apart.  This is three times closer than the June 2015 conjunction.   The planets set about 1 hour after sunset and are low in the western sky.  Find a clear horizon to locate the planetary pair.

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The June 30, 2015, Epoch Venus-Jupiter Conjunction

After the Jupiter conjunction, Venus continues to climb higher in the western sky, setting at the end of astronomical twilight on October 20.  On the way it passes Spica with the same setting time on September 13 and a close passing (2 degrees, 25 minutes) on September 18.  The reason for the difference is described in the link associated with the setting chart above.

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There is an interesting pairing of Venus and the moon on October 3.   The  3-day-old day crescent moon stands about 4 degrees above Venus.  Notice on the setting chart above that Venus and the moon set about the same time on October 2, but the pair is separated by nearly 10 degrees.  They both stand at the same altitude (not to be confused with the elevation above the ground of an airplane) in the sky, but they are closer on the next night.

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When Venus sets at the end of twilight, it leaves the western sky at the same time as Antares.  The pair is closest (3 degrees, 10 minutes) on October 26.ven_sat_ant_161029

Several nights later (November 2), Venus and Saturn set at the same time, but they are closest (3 degrees) on October 29.

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Venus continues to appear higher in the sky each night at the same time, setting later each night.  On January 12, 2017, it reaches its greatest angular separation from the sun (47 degrees), setting nearly 3.5 hours after sunset.  This is shown as GEE (greatest elongation east) on the setting chart above.  The planet is now rapidly catching our planet on its inside orbital path.  The planet continues to set later each evening reaching nearly 4 hours at the end of January 2017.  The planet begins a rapid descent toward the sun, setting about 20 minutes earlier each week during February 2017.

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Venus and Mars do not pass each other during this evening appearance of Venus.  They appear close together during the  the first several weeks of the new year (2017).  On February 3 they are are their closest (5 degrees, 24 minutes) and Venus outshines Mars nearly 200 times.

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On February  18, 2017 Venus reaches its greatest brightness (GB on the setting chart above), a brilliant spectacle in the western sky after sunset,setting nearly 3 hours, 30 minutes after the sun.  During the next month, Venus quickly sets earlier each night.  On March 14, it sets at the end of evening twilight.

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On March 18, Venus passes Mercury as the sun’s closest planet emerges from its superior conjunction.  During these times, Mercury is more difficult to see because it is not as bright as when it is closer to our planet.  This event may require binoculars to see Mercury.   The sky is very bright and Venus is just 7 days before its inferior conjunction and its reappearance in the morning sky.

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On March 25, Venus reaches its inferior conjunction, passing between the sun and Earth, completing its evening appearance.

While the charts above show the events of this evening appearance, this page will be updated with photographic images as weather permits.

Events as noted above:

  • Venus and Regulus, August 8, 2016
  • Venus and Jupiter, August 27, 2016
  • Venus and Regulus, September 18, 2016
  • Venus and Antares, October 26, 2016
  • Venus and Saturn, October 29, 2016
  • Venus and Mars, February 3, 2017

Close appearances with the moon

  • August 3, 2016 (3 degrees, 36 minutes)
  • September 2, 2016 (5d, 26m)
  • October 3, 2016 (4d, 20m)
  • November 2, 2016 (6d, 52m)
  • December 2, 2016 (7d, 50m)
  • January 1, 2017 (5d, 9m)
  • January 31, 2017 (5d, 17m)
  • February 28, 2017 (10d, 21m)
  • March 1, 2017 (15d, 51m)

2016-2017 Venus Evening Star, The Diagram

This chart shows the setting times of Venus ,the moon, planets, and stars compared to sunset during the appearance of Venus in the evening sky during 2016-2017. Chart calculated from data by the U.S. Naval Observatory.

This chart shows the setting times of Venus ,the moon, planets, and stars compared to sunset during the appearance of Venus in the evening sky during 2016-2017. Chart calculated from data by the U.S. Naval Observatory.

This chart provides the detail for the posting 2016-2017, Venus Evening Star.

The chart was plotted using data from the U.S. Naval Observatory’s MICA computer program.  All points on the chart are calculated for Chicago, Illinois .  The sunset line is the line across the bottom of the chart.  The chart shows the setting times of the objects compared to sunset, beginning June 8, 2016 (Venus’ superior conjunction) and ending March 24, 2017 (Venus’ inferior conjunction).  The latest setting time difference for any object on the chart is 5 hours after sunset.

When the Lines Cross

For all the objects that lie outside our planet’s orbital path, their setting times start at the top of the chart and set earlier each night until they disappear into the sun’s glare.  Mercury and Venus move from evening sky to morning sky and back again.  They pass behind the sun and move into the evening sky, setting higher until they reach their maximum separations from the sun and then dive between the earth and sun and move into the morning sky.  This chart has two complete evening appearances for Mercury and the start of the third as Venus moves between earth and the sun.

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When the setting lines of the celestial wonders cross, this indicates they are setting at the same time.   It does not indicate that they are closest in their approaches to each other.  The companion article, linked above describes close passings of the objects on this chart.  An excellent example of this occurs early in October 2016.  The setting chart above indicates that the moon and Venus set at nearly the same time on October 2, although they are closer on the next evening.

When the setting times of the celestial objects cross, they are setting at the same time, and they are likely to be close together sometime around the date of the cross.  One exception is Antares.  While it is near the orbital plane of the solar system, the closest approach dates can be several days before or after the simultaneous setting time.  For example, the chart indicates that Mars and Antares set at the same time on August 19, 2016, they are closest on August 24 (1.75 degrees).

Planets and Stars on the Chart

Venus is represented by the green line between its two conjunction dates.  During mid-January 2017, it sets nearly 4 hours after the sun.  It sets during twilight until late October 2016.  Locally (for Chicago) this 9 p.m. CDT.  Venus reaches its greatest separation from the sun (Greatest Elongation East — GEE on the chart) on January 12, 2017.  As it approaches our planet, it reaches its maximum brightness (GB) on February 17, 2017.

Mercury is represented by the brown lines that show its setting times during the Venus apparition;  that is, two full evening appearances and the start of the third.  It is best to observe Mercury near the time when is it near its maximum setting time difference relative to the sun.  This speedy planet usually sets during evening twilight and is never seen high in the sky when the sky is completely dark.

The setting time of the moon is represented by circles (moon dots).  The evening appearance of the moon starts near sunset and then sets later each night.  Dates are indicated for each lunar cycle at least twice.

The stars PolluxRegulusSpica, and Antares make a starry background for the visible planets.  They are near the plane of the solar system and the planets appear to move past them.  Antares is several degrees from the plane.  When a planet’s  setting line intersect’s or a moon circle appears near Antares setting time, the objects set at the same time.  This does not necessarily indicate that they are in conjunction.

Twilight

Civil twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is 6 degrees below the horizon. This is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities.

Nautical twilight is defined to begin in the morning, and to end in the evening, when the center of the sun is  12 degrees below the horizon. At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other lighting, general outlines of ground objects may be distinguishable. During nautical twilight the illumination level is such that the horizon is still visible even on a Moonless night.

Astronomical twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is 18 degrees below the horizon. Before the beginning of astronomical twilight in the morning and after the end of astronomical twilight in the evening, light from the Sun is less than that from starlight and other natural sources. For a considerable interval after the beginning of morning twilight and before the end of evening twilight, sky illumination is so faint that it is practically imperceptible. (Source)

2016: Five Planets Field Report

Photo by Tim S., February 5, 2016, Rochester Michigan. Nikon D3100. NIKKOR 10.5 mm fisheye lens. 1 second exposure at f/2.8, ISO 400.

Photo by Tim S., February 5, 2016, Rochester Michigan.
Nikon D3100. NIKKOR 10.5 mm fisheye lens. 1 second exposure at f/2.8, ISO 400.  Click the image to see it larger.

Field Report: The five naked-eye planets as seen from Rochester, Michigan on February 5, 2016.

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