The Position of Jupiter in the Night Sky:
2011 to 2014
by Martin J. Powell
The path of Jupiter against the background stars of Pisces, Aries, Taurus and Gemini from May 2011 to July 2014 (click on the thumbnail for the full-size image, 161 KB). Positions are marked on the 1st of each month. 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 late April 2012 and became visible again (in the morning sky) in early June 2012.
The chart shows the changing shape of a planet's apparent looping formation as it moves through the zodiac. Being positioned South of the ecliptic during 2011-12, Jupiter described a Southwards-facing loop in Aries, then a hybrid formation (half loop, half zig-zag) a year later in Taurus. As the planet crossed the ecliptic (heading Northwards) in Gemini in 2013-14 it described a zig-zag formation. The star map applies to observers in the Northern hemisphere (i.e. North is up); for the Southern hemisphere view, click here (163 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 (78 KB) and Southern hemisphere (79 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. Other interesting objects on the chart which are observable through telescopes and binoculars are discussed in the main text below. Night sky photographs of the region can be seen below; descriptions of the deep-sky objects (multiple stars, star clusters, nebulae and galaxies) marked on the chart can be found here.
During the first half of 2011, Jupiter was positioned in the constellation of Pisces, the Fishes, with the exception of a 12-day period (late February to early March) in which it crossed the North-western corner of Cetus, the Whale (see the 2009-11 page). In early June 2011 the planet entered Aries, the Ram, where it described a Southward-facing 'loop' in the South-western corner of that constellation. Whilst moving retrograde (East to West) in early December 2011 Jupiter returned to Pisces, reaching its Western stationary point near the Pisces/Aries border in late December of that year. Jupiter spent 35 days in Pisces then returned to Aries in early January 2012, now moving direct (West to East). As the planet approached Aries' Eastern boundary in late April 2012 it became lost from view in the evening twilight. Jupiter crossed out of sight into Taurus, the Bull, as it passed behind the Sun (as seen from the Earth) in mid-May 2012.
When the planet returned to view in the morning twilight in early June 2012 it was positioned a short distance South of the famous Pleiades star cluster (Messier 45). Jupiter's 2012-13 'hybrid' formation (half-loop, half-zigzag) was described North of the Hyades star cluster and its leading star, Aldebaran ( Tau or Alpha Tauri). The planet becaome lost from view in the evening twilight as it passed North of Orion, the Hunter in late May/early June 2013.
By the time Jupiter re-appeared in the dawn sky around mid-July 2013 it had entered Gemini, the Twins - the most Northerly constellation of the zodiac (the planet was last positioned here in 2002). The planet's 2013-14 'zigzag' formation was described in central Gemini, South-west of its brightest stars Castor ( Gem or Alpha Geminorum) and Pollux ( Gem or Beta Geminorum). From late 2013 through to mid-2014, Jupiter appeared as the Southern apex of a continually-changing triangle with Castor and Pollux. In early July 2014, shortly before Castor, Pollux and Jupiter appeared to line up, the planet headed into the evening twilight, crossing into Cancer, the Crab as it did so.
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Jupiter Opposition Data, 2010 to 2014
For the period covered by the above star map, oppositions took place on October 29th 2011, December 3rd 2012 and January 5th 2014. Around opposition, the planet is due South at local midnight in the Northern hemisphere (due North at local midnight in the Southern hemisphere).
The apparent magnitude of the planet at opposition during the period of the star chart was -2.8 (in 2011), -2.7 (in 2012) and -2.6 (in 2014). Jupiter's apparent size (i.e. its angular width as seen from the Earth, measured in arcseconds, where 1 arcsecond = 1/3600 of a degree) at opposition was 49".6 (in 2011) reducing to 48".4 (in 2012) and 46".8 (in 2014).
Superior conjunction (when Jupiter passed behind the Sun as seen from the Earth) took place on May 13th 2012, June 19th 2013 and July 24th 2014. The planet was not visible from Earth for about two weeks on either side of these dates. At superior conjunction the magnitude faded by one whole magnitude to -1.8 (in 2012), -1.7 (in 2013) and -1.6 (in 2014) and the apparent diameter reduced to 32".8 (in 2012), 32".1 (in 2013) and 31".4 (in 2014).
Data relating to Jupiter's oppositions from 2010 to 2014 are provided in the table below.
[Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]
Jupiter opposition data for the period 2010 to 2014 (click on the thumbnail for the full-size table, 43 KB). Note that there was no opposition in 2013. 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 over the period (the planet having passed perihelion in March 2011), causing its angular diameter at opposition to shrink slightly year by year. This is reflected in the planet's apparent magnitude (brightness) which faded slightly over the same period. 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 2.2. All other data was obtained from 'MegaStar', '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,
May 2011 to July 2013
Conjunctions between Jupiter and Venus are perhaps the most spectacular planetary conjunctions to view and the most photogenic. Between May 2011 and July 2014 there were three occasions when these two planets could be seen together. For Northern hemisphere observers, the conjunction of March 15th 2012 was particularly noteworthy.
The following table lists the conjunctions involving Jupiter which took place at solar elongations of greater than 15°. In several cases, other planets were also in the vicinity and these are detailed. Note that, because some of the conjunctions occurred in twilight, the planets involved may not have appeared as bright as their listed magnitude suggests.
Jupiter conjunctions with other planets from May 2011 to July 2013 (click on thumbnail for full-size table, 39 KB). Note that there were no planetary conjunctions involving Jupiter from August 2013 to July 2014. 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 2012 Mar 15, Venus was positioned 3°.3 North of Jupiter at the time shown. The 'Fav. Hem' column shows the Hemisphere in which the conjunction was best observed (Northern, Southern and/or Equatorial). 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 apparitions) or setting direction (for Dusk/Evening apparitions) for your particular latitude in the Rise-Set direction table.
Although any given conjunction takes place at a particular instant in time, it is worth pointing out that, because of the planets' relatively slow daily motions, such events are interesting to observe for several days both before and after the actual conjunction date.
There are in fact two methods of defining a planetary conjunction date: one is measured in Right Ascension (i.e. along 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 conjunction dates measured along the ecliptic are technically more accurate (separations between planets 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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Bright Stars, Nearby Stars and
Multiple Star Systems
During the period covered by the star chart, Jupiter was positioned in what is arguably the most interesting region of the entire night sky. Rich in bright stars, asterisms, star clusters and gaseous nebulae, the beginner to astronomy is well advised to become familiar with the constellations surrounding Orion and Taurus since these are ideal signposts to other constellations. Orion itself contains convenient stellar pointers towards the brightest stars in Taurus and Canis Major. A line drawn North-westwards through Orion's Belt leads one to the orange-red star Aldebaran in Taurus, the Bull. Extending the line of the Belt in the opposite direction (South-eastwards) leads one to the brightest star in the night sky, Sirius in Canis Major, the Greater Dog. Finally, a curved line extended North-eastwards from Rigel (at the South-western corner of Orion) through Mintaka (the Western star in the Belt) and Betelgeuse leads one to the star Alhena in South-western Gemini.
The six brightest stars on the star chart are (in order of descending brightness):
Note that the brightest star of all - the aforementioned Sirius ( CMa or Alpha Canis Majoris, mag. -1.4) - is not included in the above listing since, with a declination of -16°.7, it is positioned too far South of the celestial equator to appear on the chart (the Southern cut-off declination of the chart is about -7°). Sirius does however dominate this region of the sky and it cannot be overlooked in any discussion of the constellations here.
Three of these stars - namely Sirius, Procyon and Betelgeuse - form a near-equilateral triangle in the night sky which is sometimes referred to as The Winter Triangle in the Northern hemisphere because these stars are prominent in Northern hemisphere winter evenings (i.e. summer evenings in the Southern hemisphere). A photograph of these three stars can be seen in the blue box below.
Jupiter was, however, much brighter than all of these stars as it passed through the region between 2011 and 2014. With its steady light and brilliance, the planet was easily distinguished from the surrounding stellar background.
Aries & Western Taurus
Aries, Taurus, Gemini and Orion Photographs showing the region of the night sky through which Jupiter passed from mid-2011 to mid-2014 (click on the thumbnails for the full-size versions; 418 KB, 288 KB and 105 KB). The regions of the star chart which are visible in the photographs can be see by clicking on the thumbnail (left, 65 KB). For the Gemini photo, stars are visible down to about magnitude +6.5; for the Taurus photo, the limiting magnitude is about +8.0 and for the Aries photo it is about +7.5. Note that the photographs do not have the same scale because of the varying camera lens settings and image resolutions.
As it slowly moved along the 'celestial highway' known as the ecliptic (the apparent path along which the Sun, Moon and planets move through zodiac) Jupiter passed numerous bright stars; these are listed below, in chronological order:
In the introduction it was mentioned that Jupiter, Castor and Pollux formed a variety of triangle shapes in the night sky from around late 2013 to around mid-2014. Observers with a geometrical leaning may be interested to know the dates on which the three celestial bodies formed right-angled and isosceles triangles. The first right-angled triangle was formed on August 4th 2013 (with Castor at the perpendicular angle) when Jupiter was moving direct and was visible in the morning sky. The distance between Castor and Jupiter on this occasion (i.e. the length of the adjacent side of the triangle) was 16°.2. On August 22nd 2013 they formed an isosceles triangle, with Jupiter at the Southern apex, the long sides of the triangle measuring 13°. Three weeks later (September 12th) a second right-angled triangle was formed, this time with Pollux at the perpendicular angle, 10°.1 North-east of Jupiter. On January 2nd 2014, just three days before Jupiter's opposition, the three again formed a right-angled triangle with Pollux at the perpendicular angle, 9°.9 North-east of Jupiter. After entering the evening sky, with the planet still retrograding, a second isosceles triangle was formed between the three on January 29th 2014, the long sides on this occasion measuring 12°.7. The last isosceles triangle was formed on April 11th 2014, the long sides measuring 12°.6, Jupiter now having returned to direct motion. The finale of this trigonometrical menagerie took place on May 9th 2014 with a right-angled triangle, Pollux again being at the perpendicular angle, 9°.5 distant from Jupiter.
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Jupiter Transit Altitudes, 2010 to 2014
In the 2007-8 period, observers at mid-Northern latitudes saw Jupiter at its lowest meridian transit altitude for some twelve years, as the planet traversed the Southernmost constellations of the zodiac. Observing circumstances for Northern hemisphere observers have gradually improved after 2009, when the planet began to ascend the ecliptic once more, moving North-eastwards through Capricornus, Aquarius and Pisces (Jupiter crossed the celestial equator in February 2011).
Conversely, during 2007-8, observers in mid-Southern latitudes saw Jupiter high up in the sky when it reached meridian transit (due North in the Southern hemisphere) providing optimal viewing conditions for telescopic observers. From 2012 to 2014, as the planet passed through the most Northerly constellations of the zodiac, observers at mid-Southern latitudes saw the transit altitude reduce quite considerably.
Transit altitudes of Jupiter at successive oppositions from 2010 to 2014, as seen from a variety of latitudes (click on thumbnail for full-size table, 33 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 2012/13 apparition at latitude 40° North, the transit altitude of Jupiter ranged from (71°.3 - 2°.0) = 69°.3 to (71°.3 + 2°.0) = 73°.3. The table demonstrates that, from 2010 through to 2014, Jovian transit altitudes improved for Northern hemisphere observers but worsened somewhat for Southern hemisphere observers.
What are the best and worst case scenarios regarding Jupiter's transiting altitude? Northern hemisphere observers witnessed their worst case scenario (and Southern hemisphere observers witnessed their best) in the 2007-8 observing season, when Jupiter passed through the Southernmost zodiac constellations (see table on the 2009-11 page). Jupiter reached its most Northerly point along the ecliptic in the 2013/14 apparition, when it was positioned in Gemini. Observers at mid-Northern latitudes then saw the planet transit at around 60° to 70° high in the sky (best case scenario); mid-Southern hemisphere observers fared rather worse, the planet transiting at only 20° to 30° high (worst case scenario).
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Moon near Jupiter Dates,
January to June 2014
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 during the first half of 2014 the Moon was in the vicinity of the planet:
Moon near Jupiter dates from January to June 2014 (click on thumbnail for full-size table, 24 KB). No entry is given for July because in this month, Jupiter was too close to the Sun - and therefore not observable - when the Moon was nearby. 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 are 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 April 6th at 22:31 UT, Jupiter was 5°.4 North 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). Moon near Jupiter dates can also be viewed for the years 2012 (37 KB) and 2013 (36 KB).
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 June 2011
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