The Position of Jupiter in the Night Sky:
2014 to 2018
by Martin J. Powell
The path of Jupiter against the background stars of Cancer, Leo, Virgo and Libra from September 2014 to November 2018, with positions marked on the 1st of each month (click on the thumbnail for full-size image, 162 KB). Periods when the planet was unobservable (i.e. when it was too close to the Sun, or passed behind it) are indicated by a dashed line; hence the planet became lost from view (in the evening sky) in early August 2015 and became visible again (in the morning sky) in mid-September 2015.
The chart shows the changing shape of a planet's apparent looping formation as it moves through the zodiac. Having crossed the ecliptic (the apparent path of the Sun, Moon and planets) in a Northward direction in late 2013, Jupiter described a hybrid loop (half loop, half zig-zag) on the Cancer-Leo border in 2014-15, followed by three Northward-facing loops as it headed Southward through Leo, Virgo and Libra over the next three years. The star map applies to observers in the Northern hemisphere (i.e. North is up); for the Southern hemisphere view, click here (166 KB).
The faintest stars on the map have an apparent magnitude of about +4.8. Printer-friendly versions of this chart are available for Northern (76 KB) and Southern hemisphere (78 KB) views. Astronomical co-ordinates of Right Ascension (longitude, measured Eastwards in hrs:mins from the First Point of Aries) and Declination (latitude, measured in degrees North or South of the celestial equator) are marked around the border of the chart. Click here to see a 'clean' star map of the area (i.e. without planet path); a printable version can be found here. Night sky photographs of the region can be seen below; descriptions of the deep-sky objects in Cancer, Leo and Virgo which are marked on the chart can be found here.
Having spent the 2013-14 observing period among the stars of the zodiac's most Northerly constellation of Gemini, the Twins, Jupiter re-appeared in the dawn sky in August 2014 in the neighbouring constellation of Cancer, the Crab, positioned not far from the celebrated star cluster named Praesepe or The Beehive (Messier 44 or NGC 2632).
Jupiter imaged by Puerto Rican amateur astronomer Efrain Morales Rivera on February 27th 2014 using an 8-inch Ritchey-Chrétien telescope fitted with a CCD camera (click on the thumbnail for a larger image, 6 KB) (Image: Jaicoa Observatory)
Jupiter described its 2014-15 'hybrid' loop on the Cancer-Leo border, the planet crossing into Leo, the Lion, in mid-October 2014 and attaining its Eastern stationary point in December of that year. The planet retrograded (moved East to West) back into Cancer in early February 2015 and just 2 days later reached opposition some 17' (17 arcminutes or 0°.3, where 1 arcminute = 1/60th of a degree) from Cancer's Eastern border. Western stationary point was reached in April 2015, after which the planet resumed direct motion (West to East) and re-entered Leo two months later. Jupiter headed out of view in the evening twilight in early August 2015, the planet passing just to the North of Leo's brightest star Regulus ( Leonis, apparent magnitude +1.3) soon afterwards.
Jupiter re-appeared in the dawn sky in mid-September 2015, positioned in central Southern Leo, marking the start of the planet's 2015-16 apparition. The planet reached its January 2016 Eastern stationary point just inside Leo's Eastern border, then retrograded towards a March opposition positioned just 40' (0°.7) West of the star Sigma Leonis ( Leo, mag. +4.0), the rear paw of the Lion. Western stationary point was reached in May 2016, after which the planet resumed direct motion, entering Virgo, the Virgin, in early August. Jupiter became lost in the evening twilight during early September, crossing the celestial equator - where the declination is 0° ( = 0°) - in mid-September. Six days later, the planet passed through its 2016 superior conjunction, when it was positioned directly behind the Sun as seen from the Earth.
Jupiter emerged in the dawn Eastern sky in mid-October 2016, heralding the 2016-17 apparition which saw the planet occupying central Virgo throughout. In early 2017 the planet was positioned around 4° North of the constellation's brightest star Spica ( Vir or Alpha Virginis, mag. +1.0) and moving in a South-easterly direction against the background stars. Eastern stationary point was reached in early February, after which the planet turned retrograde and headed North-westwards, passing North of Spica a second time around mid-month. Opposition took place in early April, positioned just 16' (0°.3) West of the double star Theta Virginis ( Vir, mag. +4.4). After reaching Western stationary point in June the planet resumed direct motion, heading South-easterly again and passing North of Spica for a third and final time in early September. The 2016-17 apparition ended in early October, as Jupiter sank into the Western sky at dusk.
Jupiter in Gemini, the Twins photographed by the writer two days before the planet's opposition in January 2014 (click on the thumbnail for the full-size photo, 56 KB). An annotated version of the photo can be seen here (26 KB). Jupiter was positioned in Gemini for a little over a year between 2013 and 2014, reaching its highest point in the zodiac in March 2014. Throughout the period the planet formed a variety of triangle shapes with the constellation's two brightest stars Castor and Pollux.
As 2017 drew to a close, Jupiter re-emerged in the dawn sky and the 2017-18 apparition commenced, the planet having just entered the constellation of Libra, the Balance. The entire apparition took place within the confines of this unremarkable constellation, the planet's Northward-facing loop being described to the North and East of its second-brightest star Zuben Elgenubi ( Lib or Alpha Librae, mag. +2.7). In mid-December 2017 Jupiter was a morning object and passed less than a degree North of the star. At the start of 2018 the planet was positioned around 2° East of it, continuing South-eastwards to reach its Eastern stationary point in March. The planet turned retrograde and headed North-westwards, reaching opposition in early May, some 3° East of Zuben Elgenubi. The planet passed North of the star again in early June then reached its Western stationary point in mid-July. Having resumed direct motion Jupiter proceeded South-eastwards and passed North of Zuben Elgenubi one more time in mid-August. The 2017-18 apparition closed as Jupiter disappeared into the evening twilight in early November 2018. Soon afterwards, the King of the Planets left Libra and headed into the Southernmost constellations of the zodiac.
[Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]
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Jupiter Opposition Data, 2015 to 2018
Data relating to Jupiter's oppositions from 2015 to 2018 are provided in the table below:
Jupiter opposition data for the period 2015 to 2018 (click on thumbnail for full-size image, 41 KB). The Declination is the angle of the planet to the North (+) or South (-) of the celestial equator; on the star chart, it represents the planet's angular distance above or below the blue line. The angular diameter (or apparent size) of the planet as seen from Earth is given in arcseconds (where 1 arcsecond = 1/3600th of a degree). The Polar Diameter is 6.3% less than the Equatorial Diameter because Jupiter is an oblate spheroid.
Jupiter's opposition distance from Earth slowly increased through to 2017, so that its angular diameter at opposition shrank slightly year by year. This is reflected in the planet's apparent magnitude (brightness) which faded slightly over the same period. The planet passed through aphelion - its most distant orbital point from the Sun - in February 2017. From 2018, Jupiter's opposition distance from Earth began to reduce once more. The Tilt (the inclination of Jupiter's rotational axis relative to the Earth's orbital plane) is positive (+) when Jupiter's Northern hemisphere is tipped towards the Earth and negative (-) when its Southern hemisphere is tipped towards the Earth; the maximum value it can attain is ±3°.4.
The Tilt values were obtained from NASA's Jupiter Ephemeris Generator 2.5. All other data was obtained from 'Redshift' and 'SkyGazer Ephemeris' software. The Jupiter images were obtained from NASA's Solar System Simulator.
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Jupiter Conjunctions with other Planets,
August 2014 to December 2018
Conjunctions between Jupiter and Venus are perhaps the most spectacular of all to view and the most photogenic. Between August 2014 and December 2018 there were six occasions when these two planets could be seen together. The conjunction of October 26th 2015 was particularly good for Northern hemisphere observers whilst that of July 1st 2015 was particularly good for Southern hemisphere observers. The October 26th 2015 conjunction took place on the very same day as Venus' greatest Western elongation, which means that it was positioned at the greatest angular distance from the Sun which is technically possible for a conjunction with Venus to take place.
Two conjunctions of Jupiter with Mars took place during the period in question, all of them morning events. For Northern hemisphere observers the conjunction of October 17th 2015 was the best, with Venus joining in the spectacle several degrees away. The Jupiter-Mars conjunction of January 7th 2018 was favourable for both Northern and Southern hemispheres, the separation between the two planets (12 arcminutes or 0°.2) being the closest of the two conjunctions.
The following table lists the conjunctions involving Jupiter which took place at solar elongations of greater than 15°. In several cases, other planets and/or stars were also in the vicinity and these are detailed. Note that, because some of the conjunctions occured in twilight, the planets involved may not have appeared as bright as their listed magnitude suggests.
Jupiter conjunctions with other planets from August 2014 to December 2018 (click on thumbnail for full-size table, 48 KB). The column headed 'UT' is the Universal Time (equivalent to GMT) of the conjunction (in hrs : mins). The separation (column 'Sep') is the angular distance between the two planets, measured relative to Jupiter, e.g. on 2016 Aug 27, Venus was positioned 0°.1 North of Jupiter at the time shown. The 'Favourable Hemisphere' column shows the Hemisphere in which the conjunction was best observed. The expression 'Not high N Lats' indicates that observers at latitudes further North than about 45°N will have found the conjunction difficult or impossible to observe because of low altitude and/or bright twilight.
In the 'When Visible' column, a distinction is made between Dawn/Morning visibility and Dusk/Evening visibility; the terms Dawn/Dusk refer specifically to the twilight period before sunrise/after sunset, whilst the terms Evening/Morning refer to the period after darkness falls/before twilight begins (some conjunctions take place in darkness, others do not, depending upon latitude). The 'Con' column shows the constellation in which the planets were positioned at the time of the conjunction.
To find the direction in which the conjunctions were seen on any of the dates in the table, note down the constellation in which the planets were located ('Con' column) on the required date and find the constellation's rising direction (for Dawn/Morning conjunctions) or setting direction (for Dusk/Evening conjunctions) for your particular latitude in the Rise-Set direction table.
There are in fact two methods of defining a planetary conjunction date: one is measured in Right Ascension (i.e. perpendicular to the celestial equator) and the other is measured along the ecliptic, which is inclined at 23½° to the Earth's equatorial plane (this is due to the tilt of the Earth's axis in space). An animation showing how conjunction dates are determined by each method can be found on the Jupiter-Uranus 2010-11 triple conjunction page. Although conjunctions measured along the ecliptic can be significantly closer, the Right Ascension method is the more commonly used, and it is the one which is adopted here.
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Constellations of the Zodiac: Photographs
Libra & Northern Scorpius
Leo, Virgo & Coma Berenices
Cancer & Northern Hydra
Cancer, Leo, Virgo and Libra Photographs showing the region of the night sky through which Jupiter passed from mid-2014 to late 2018 (click on thumbnails for full-size versions: 57 KB, 282 KB and 187 KB). The regions of the star chart which are visible in the photographs can be seen by clicking on the thumbnail at left (53 KB). For the Cancer photo, stars are visible down to about +8.2; for the Leo and Virgo photo, the limiting magnitude is about +7.0 and for the Libra photo it is also about +7.0. Note that the photographs do not have the same scale because of the varying camera lens settings and image resolutions.
As it slowly moves along the 'celestial highway' known as the ecliptic (the apparent path along which the Sun, Moon and planets move through zodiac) Jupiter passes numerous bright stars; the bright stars passed by the planet between August 2014 and December 2018 are listed below, in chronological order:
Details of other interesting objects in the region (star clusters, variable stars, nebulae, galaxies, etc) can be found on the Zodiacal Sky: Cancer-Leo-Virgo page.
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Jupiter Transit Altitudes, 2015 to 2018
From 2015 to 2018, observers at mid-Northern latitudes saw Jupiter's transit altitude reduce significantly year by year as the planet headed Southward through Leo, Virgo and Libra, the planet crossing the celestial equator in September 2016. For Southern hemisphere observers, viewing circumstances improved year-on-year throughout the period.
Transit altitudes of Jupiter at successive oppositions from 2015 to 2018, as seen from a variety of latitudes (click on thumbnail for full-size table, 30 KB). The Declination (Dec.) is the angle of the planet to the North (+) or South (-) of the celestial equator at the time of the planet's opposition. The Altitude Range is the approximate altitude variation over the course of the apparition, e.g. for the 2015/16 apparition at latitude 40° North, the transit altitude of Jupiter ranged from (55°.9 - 4°.1) = 51°.8 to (55°.9 + 4°.1) = 60°.0. The table demonstrates that, from 2015 through to 2018, Jovian transit altitudes improved for Southern hemisphere observers but worsened for Northern hemisphere observers.
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Moon near Jupiter Dates, 2018
The Moon is easy to find, and on one or two days in each month, it passes Jupiter in the sky. Use the following table to see on which dates the Moon was in the vicinity of the planet:
Moon near Jupiter dates for 2018 (click on thumbnail for full-size table, 37 KB). No dates are shown for December because Jupiter was too close to the Sun to view during this month. The Date Range shows the range of dates worldwide (allowing for Time Zone differences across East and West hemispheres). Note that the dates, times and separations at conjunction (i.e. when the two bodies were at the same Right Ascension) are measured from the Earth's centre (geocentric) and not from the Earth's surface (times are Universal Time [UT], equivalent to GMT). The Sep. & Dir. column gives the angular distance (separation) and direction of the planet relative to the Moon, e.g. on May 27th at 17:39 UT, Jupiter was 3°.9 South of the Moon's centre. The Moon Phase shows whether the Moon was waxing (between New Moon and Full Moon), waning (between Full Moon and New Moon), at crescent phase (less than half of the lunar disk illuminated) or gibbous phase (more than half but less than fully illuminated).
The Moon moves relatively quickly against the background stars in an Eastward direction, at about its own angular width (0º.5) each hour (about 12º.2 per day). Because it is relatively close to the Earth, an effect called parallax causes it to appear in a slightly different position (against the background stars) when seen from any two locations on the globe at any given instant; the further apart the locations, the greater the Moon's apparent displacement against the background stars. Therefore, for any given date and time listed in the table, the Moon will have appeared closer to Jupiter when seen from some locations than from others. For this reason, the dates shown in the table should be used only for general guidance.
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Copyright Martin J Powell July 2014
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