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Finding Mars from The Big Dipper (The Plough), September 2011 to August 2012

Mars Observational Data, Sep 2011 to Aug 2012

Mars Conjunctions with other Planets, 2011-13

Moon nr Mars, May 2011 - Feb 2013

Mars Oppositions, 2012-27

The Martian Seasons

Paths of Mars and Saturn from September 2011 to August 2012 (Copyright Martin J Powell 2011)

The path of Mars against the background stars of Gemini, Cancer, Leo and Virgo from September 2011 to August 2012, shown at 10-day intervals. During this apparition, Mars described a typical, Northward-facing loop, as it had done in the planet's previous apparition (see the 2009-10 page). A close-up of the planet's path through the M44 (Praesepe) star cluster in Cancer is shown below.

The star map applies to observers in the Northern hemisphere (i.e. North is up); for the Southern hemisphere view, click here. The faintest stars shown on the map have an apparent magnitude of about +4.8. Printer-friendly versions of this chart are available for Northern and Southern hemisphere views. Astronomical co-ordinates of Right Ascension (longitude, measured Eastwards in hrs:mins) and Declination (latitude, measured in degrees North or South of the celestial equator) are marked around the border of the chart. Night sky photographs of the region can be seen below; descriptions of the deep-sky objects (double stars, star clusters and galaxies) marked on the chart can be found here.

The Mars Apparition of 2011-2013

by Martin J. Powell

Following superior conjunction on February 4th 2011 (when it passed directly behind the Sun) Mars passed through the perihelion point in its orbit (i.e. its closest point to the Sun) on March 9th. The planet was then positioned 1.3814 Astronomical Units (206.6 million kms or 128.4 million miles) from the Sun and 2.3606 AU (353.1 million kms / 219.4 million miles) from the Earth. Its first appearance in the dawn sky (rising in the East before sunrise) took place from around early May, visible from Equatorial and Southern hemisphere latitudes. From mid-Northern latitudes its appearance began around late May. At high Northern latitudes, the long summer twilight delayed Mars' appearance until around mid-July, by which time the planet was rising some three hours before the Sun.

Two months into the apparition, Mars appeared as a feeble, pale-orange star of apparent magnitude +1.3, barely gaining any significant altitude (angle above the horizon) before disappearing into the brightening twilight. Telescopically Mars was a disappointing sight at this time, its low altitude and tiny apparent size frustrating most attempts to obtain a steady and clear view of the planet's surface. Around mid-July the Martian disk appeared just 4.2 arcseconds across (where 1 arcsecond = 1/3600th of a degree) with a gibbous phase of about 96% illumination. By late July 2011, the Northern hemisphere summer twilight had receded sufficiently for Mars to become clearly visible to observers at high Northern latitudes, rising in the North-eastern sky about 3 hours before sunrise. By mid-August 2011, the planet was rising in darkness from all but the Polar regions of the world.

After emerging in the dawn sky, Mars moved steadily Eastwards (direct motion) through the following constellations, its brightness varying with its changing distance and aspect as seen from the Earth:

Date Range

Constellation

<----- Mid-Period ----->

Apparent Magnitude

Apparent

Diameter

(arcsecs)

Solar

Elongation

2011

Apr 13 to May 10

Astrological symbol of Pisces

Pisces

+1.2

4".0

17W

May 10 to Jun 12

Astrological symbol of Aries

Aries

+1.3

4".1

23W

Jun 12 to Aug 3

Astrological symbol of Taurus

Taurus

+1.4

4".2

33W

Aug 3 to Sep 15

Astrological symbol of Gemini

Gemini

+1.4

4".6

47W

Table showing the position and apparent magnitude of Mars for the early part of the 2011-2012 apparition. The magnitudes, diameters and solar elongations listed here refer to the middle of the period in question. Mars began the apparition in Pisces, rising in the East before sunrise, then headed Northwards along the ecliptic through Aries and Taurus before reaching its most Northerly declination for this apparition (+23.8) in Gemini. In this and the tables which follow, the rising and setting directions of the constellations listed can be found by referring to the zodiacal constellation rise-set direction table.

On August 31st 2011, Mars passed 0.9 North of the star Wasat (Greek lower-case letter 'delta' Gem or Delta Geminorum, magnitude +3.5) in the constellation of Gemini, the Twins. Three days later it passed 9.1 South of Castor (Greek lower-case letter 'alpha' Gem or Alpha Geminorum, mag. +1.6), Gemini's second-brightest star and then 5.8 South of Gemini's brightest star Pollux (Greek lower-case letter 'beta' Gem or Beta Geminorum, mag. +1.1) on September 9th.

On September 15th the Red Planet entered Cancer, the Crab, the zodiac's faintest constellation. Located at its centre is a well-known open cluster called Praesepe (pronounced 'pree-SEE-pee') or alternatively, The Beehive Cluster (designated Messier 44 or NGC 2632). This large star cluster can be glimpsed with the naked-eye from dark locations as a hazy patch of light; through binoculars it is an easy and pretty sight. Mars crossed the Praesepe star cluster between October 1st and 2nd, passing a little to the South of its centre (see the photograph below).

The path of Mars through the Praesepe star cluster (M44) in early October 2011 (Copyright Martin J Powell, 2011)

 

The planet Mars in Gemini in December 2007. Click for a full-size photo (Copyright Martin J Powell, 2007)

In early October 2011, Mars crossed the open cluster M44 (Praesepe) in the constellation of Cancer (move your pointer over the image - or click here - to see the track of the planet, marked at 0h UT on each date).

 

Mars in Gemini, 2007  The Red Planet reached opposition in Western Gemini on Christmas Eve 2007; this photograph was taken about a week before that date, when it shone at magnitude -1.5 (move your cursor over the image - or click here - to identify the stars, and click for a full-size picture).

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The following day (October 3rd) Mars passed 1.1 North of the star Asellus Australis (Greek lower-case letter 'delta' Cnc or Delta Cancri, mag. +3.9) and six days later, 6.5 North of Acubens (Greek lower-case letter 'alpha' Cnc or Alpha Cancri, mag. +4.5). On October 19th the planet moved from Cancer into Leo, the Lion, where it would spend the brighter part of the 2011-13 apparition.

Three weeks after entering Leo - on November 10th 2011 - Mars passed 1.4 North of that constellation's brightest star Regulus (Greek letter Alpha Leonis or Alpha Leonis, mag. +1.3 - for more details, see below). On December 2nd, Mars reached western quadrature (90 West of the Sun). When seen from the Earth, the planet then showed its minimum phase (the percentage of the planet's disk which is illuminated - in this case, 89%) making it appear distinctly gibbous when seen through telescopes.

On December 25th 2011 (Christmas Day) Mars passed 1.2 North of the fourth-magnitude star Greek lower-case letter 'sigma' Leonis (Sigma Leonis) at the foot of the Lion's hind leg. Now positioned well into the Southern section of its 2011-12 loop, Mars' daily apparent motion through the night sky slowed as the Earth began to 'catch up' with the planet in its slower and more distant orbit around the Sun.

With the arrival of 2012 Mars began to brighten significantly as the distance between the Earth and the Red Planet continued to reduce. Now shining at magnitude -0.1, Mars appeared distinctly orange and non-stellar to the naked-eye, outshining all the stars in this region of the night sky. As the planet headed into the constellation of Virgo, the Virgin for a three-week period beginning on January 14th, it was brightening day by day. Through telescopes, the Martian disk now had an apparent diameter of about 10" (10 arcseconds), revealing considerable surface detail.

On January 25th 2012, mid-way through its vacation in VirgoMars reached its Eastern stationary point, 8.7 SSW of  the Lion's tail-star Denebola (Greek lower-case letter 'beta' Leo or Beta Leonis, mag. +2.1) and 1.6 WSW of the fourth-magnitude variable star Greek lower-case letter 'nu' Virginis (Nu Virginis, located just across the border in Virgo). Now moving retrograde (i.e. moving from East to West against the stellar background), Mars returned to Leo on February 3rd.

Mars reached aphelion (the most distant point in its orbit from the Sun) on February 15th 2012, when it was 1.6659 AU (249.2 million kms / 154.8 million miles) from the Sun and 0.7129 AU (106.6 million kms / 66.2 million miles) from the Earth. For the Earthbound observer, Mars' aphelion passage at this crucial stage of the apparition was very significant, since it explained why the 2011-13 apparition was the worst for 17 years.

Accelerating into the retrograde stage of its loop, Mars passed 2 South of the fourth-magnitude double star Greek lower-case letter 'iota' Leonis (Iota Leonis) - on February 19th 2012 and two days later, 2.7 North of Greek lower-case letter 'sigma' Leonis.

Mars reached opposition (when it was directly opposite the Sun in the sky and brightest for this apparition) on the night of March 3rd 2012, positioned 5.4 SSW of the star Coxa (Greek lower-case letter 'theta' Leo or Theta Leonis, mag. +3.9) and 4.5 West of  Greek lower-case letter 'iota' Leonis. This was not, however, Mars' closest point to the Earth during this apparition; because of the eccentricity of its orbit, Mars' perigee (its closest point to Earth) took place two days later - on March 5th - when it was 0.6737 AU (100.7 million kms / 62.6 million miles) from the Earth.

At opposition, a superior planet rises around sunset, is visible throughout the night and sets around sunrise. Its highest point in the sky is reached when it crosses the observer's meridian at local midnight (due South at midnight in the Northern hemisphere and due North at midnight in the Southern hemisphere).

On opposition day in 2012, Mars shone at magnitude -1.2 and had an apparent disk diameter of 13".9. This was not as bright nor as large (when seen through a telescope) as it was at its previous opposition in January 2010, when the planet reached magnitude -1.3 and had an apparent diameter of 14".1. Indeed, its opposition disk size and brightness in 2012 had not been so poor since the opposition of February 1995. Such distant and dim oppositions, taking place when the planet is near the aphelion position in its orbit, are often referred to as aphelic oppositions.

Date

Constellation

Apparent

Magnitude

Apparent

Diameter

(arcsecs)

Tilt

View from

Earth

(0h UT)

(North up)

Distance (AU)*

Solar

Elongation

Illuminated

Phase

Central

Meridian

Longitude

(0h UT)

from Earth

from Sun

2011

 Sep 5

Astrological symbol of Gemini

Gem

+1.4

4".8

+11.5

View of Mars from Earth on September 5th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.9708

1.5468

51W

93%

145

Sep 15

Astrological symbol of Gemini

Gem

+1.4

4".9

+13.9

View of Mars from Earth on September 15th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.9145

1.5593

54W

92%

048

Sep 25

Astrological symbol of Cancer

Cnc

+1.3

5".1

+16.0

View of Mars from Earth on September 25th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.8530

1.5714

58W

92%

311

Oct 5

Astrological symbol of Cancer

Cnc

+1.3

5".2

+17.9

View of Mars from Earth on October 5th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.7863

1.5830

61W

91%

214

Oct 15

Astrological symbol of Cancer

Cnc

+1.2

5".5

+19.5

View of Mars from Earth on October 15th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.7148

1.5941

66W

91%

117

Oct 25

Astrological symbol of Leo

Leo

+1.2

5".7

+20.9

View of Mars from Earth on October 25th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.6386

1.6046

70W

90%

021

Nov 4

Astrological symbol of Leo

Leo

+1.1

6".0

+22.0

View of Mars from Earth on November 4th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.5578

1.6144

75W

90%

284

Nov 14

Astrological symbol of Leo

Leo

+1.0

6".4

+22.8

View of Mars from Earth on November 14th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.4733

1.6235

79W

90%

187

Nov 24

Astrological symbol of Leo

Leo

+0.8

6".8

+23.4

View of Mars from Earth on November 24th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.3855

1.6318

85W

89%

091

Dec 4

Astrological symbol of Leo

Leo

+0.7

7".2

+23.8

View of Mars from Earth on December 4th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.2951

1.6393

90W

89%

356

Dec 14

Astrological symbol of Leo

Leo

+0.5

7".8

+23.9

View of Mars from Earth on December 14th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.2035

1.6459

97W

90%

261

Dec 24

Astrological symbol of Leo

Leo

+0.4

8".4

+23.8

View of Mars from Earth on December 24th 2011 at 0h UT (Image from NASA's Solar System Simulator v4)

1.1118

1.6516

103W

90%

166

 2012

Jan 3

Astrological symbol of Leo

Leo

+0.2

9".2

+23.6

View of Mars from Earth on January 3rd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.0218

1.6564

111W

91%

072

Jan 13

Astrological symbol of Leo

Leo

-0.1

10".0

+23.4

View of Mars from Earth on January 13th 2012 at 0h UT (Image from NASA's Solar System Simulator v4.0)

0.9356

1.6602

119W

92%

339

Jan 23

Astrological symbol of Virgo

Vir

-0.3

10".9

+23.1

View of Mars from Earth on January 23rd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.8559

1.6631

129W

94%

248

Feb 2

Astrological symbol of Virgo

Vir

-0.6

11".9

+22.8

View of Mars from Earth on February 2nd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.7860

1.6650

139W

96%

157

Feb 12

Astrological symbol of Leo

Leo

-0.8

12".8

+22.6

View of Mars from Earth on February 12th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.7300

1.6659

151W

97%

068

Feb 22

Astrological symbol of Leo

Leo

-1.1

13".5

+22.3

View of Mars from Earth on February 22nd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.6917

1.6657

164W

99%

340

Mar 3

Astrological symbol of Leo

Leo

-1.2

13".9

+22.1

View of Mars from Earth on March 3rd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.6744

1.6646

175W

99%

253

Mar 13

Astrological symbol of Leo

Leo

-1.1

13".8

+22.0

View of Mars from Earth on March 13th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.6795

1.6625

166E

99%

167

Mar 23

Astrological symbol of Leo

Leo

-0.9

13".3

+21.9

View of Mars from Earth on March 23rd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.7057

1.6595

153E

98%

079

Apr 2

Astrological symbol of Leo

Leo

-0.7

12".5

+22.0

View of Mars from Earth on April 2nd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.7500

1.6554

141E

96%

350

Apr 12

Astrological symbol of Leo

Leo

-0.5

11".6

+22.2

View of Mars from Earth on April 12th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.8080

1.6504

131E

94%

260

Apr 22

Astrological symbol of Leo

Leo

-0.2

10".7

+22.7

View of Mars from Earth on April 22nd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.8760

1.6445

121E

92%

168

May 2

Astrological symbol of Leo

Leo

-0.0

9".9

+23.3

View of Mars from Earth on May 2nd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

0.9504

1.6377

113E

91%

076

May 12

Astrological symbol of Leo

Leo

+0.2

9".1

+24.0

View of Mars from Earth on May 12th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.0284

1.6301

106E

90%

342

May 22

Astrological symbol of Leo

Leo

+0.4

8".5

+24.7

View of Mars from Earth on May 22nd 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.1080

1.6216

99E

89%

248

Jun 1

Astrological symbol of Leo

Leo

+0.5

7".9

+25.3

View of Mars from Earth on June 1st 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.1878

1.6123

93E

89%

152

Jun 11

Astrological symbol of Leo

Leo

+0.6

7".4

+25.7

View of Mars from Earth on June 11th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.2664

1.6024

88E

89%

056

Jun 21

Astrological symbol of Leo

Leo

+0.8

7".0

+26.0

View of Mars from Earth on June 21st 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.3432

1.5917

83E

89%

320

Jul 1

Astrological symbol of Virgo

Vir

+0.9

6".6

+26.1

View of Mars from Earth on July 1st 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.4174

1.5805

79E

89%

223

Jul 11

Astrological symbol of Virgo

Vir

+0.9

6".3

+25.9

View of Mars from Earth on July 11th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.4886

1.5688

75E

89%

126

Jul 21

Astrological symbol of Virgo

Vir

+1.0

6".0

+25.4

View of Mars from Earth on July 21st 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.5566

1.5566

71E

89%

028

Jul 31

Astrological symbol of Virgo

Vir

+1.1

5".8

+24.6

View of Mars from Earth on July 31st 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.6210

1.5440

67E

89%

291

Aug 10

Astrological symbol of Virgo

Vir

+1.1

5".6

+23.5

View of Mars from Earth on August 10th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.6819

1.5312

63E

90%

193

Aug 20

Astrological symbol of Virgo

Vir

+1.2

5".4

+22.0

View of Mars from Earth on August 20th 2012 at 0h UT (Image from NASA's Solar System Simulator v4)

1.7392

1.5182

60E

90%

095

* 1 AU (Astronomical Unit) = 149,597,870 kms (92,955,806 statute miles)

Table of selected data relating to the brighter part of the Mars apparition of 2011-13. The data is listed at 10-day intervals, corresponding with the dates on the star map. The Central Meridian Longitude (provided for telescopic observers) is the Martian longitude which appeared at the centre of the disk when seen from the Earth at the time indicated (0h Universal Time, or 0h GMT). A Martian longitude map by Damian Peach showing the surface features can be seen at the BAA Mars Section website (note that the map is shown with South up, matching the inverted view seen through astronomical telescopes). For example, when CM = 290, Syrtis Major appears at the centre of the disk. The Central Meridian Longitude increases by 14.6 every hour, so this allowance should be applied for observations at other times (if the result is greater than 360, subtract 360 to obtain the correct longitude). Those wishing to observe Mars telescopically should consider downloading the free 'Mars Previewer II ' software by Leandro Rios, available as a ZIP file at Sky & TelescopeThe data for the table was obtained from 'MegaStar', 'SkyGazer Ephemeris'  and 'Mars Previewer II' software and the Martian disk images were derived from NASA's Solar System Simulator.

Having passed opposition, Mars entered the evening sky (rising before sunset) and began to fade as its distance from Earth increased once more. The planet reached its Western stationary point, some 4.3 ENE of Regulus, on April 16th, after which it resumed direct motion (West to East) against the background stars. In early May 2012, with the advancing Northern hemisphere summer twilight, observers positioned North of about 60 North latitude effectively lost their view of Mars as the evening sky became too light for the planet to be seen.

By the time Mars reached eastern quadrature (90 East of the Sun) on June 8th the planet had faded considerably to magnitude +0.5, its apparent diameter having fallen below 8" and its phase having shrunk from 100% (at opposition) to 89%. Three days later (June 11th) Mars passed 0.9 South of Greek lower-case letter 'sigma' Leonis and continued to head towards Leo's South-eastern boundary.

Mars entered Virgo on June 21st 2012 as it proceeded South-eastwards, a little to the North of the ecliptic (the apparent path along which the Sun, Moon and planets move). Its Eastern elongation from the Sun slowly narrowing, Mars passed close to several bright stars (and one planet) in Virgo over the following two months.

On June 28th Mars passed 0.2 South of the star Zavijah or Zavijava (Greek lower-case letter 'beta' Vir or Beta Virginis, mag. +3.6). For several hours centred around 10:00 UT, the narrow separation of the two celestial bodies made them resemble an easy naked-eye double star, Mars being the brighter of the pair and of course, coloured pale orange. Zavijah is technically a yellow star although this is difficult to detect through binoculars and telescopes.

With Mars' solar elongation reducing to 70 by mid-July, observers in higher Northern hemisphere latitudes began to have some difficulty viewing the planet after sunset as it began to languish low down in the summer dusk sky. From these latitudes, the lengthy twilight and the shallow angle of the ecliptic to the Western horizon after sunset combined to worst effect, positioning the planet low down in the West at dusk, thus making it difficult to view.

On July 13th 2012 Mars passed 1.3 South of the star Zaniah (Greek lower-case letter 'eta' Vir or Eta Virginis, mag. +3.9) and eleven days later (July 24th) 3 South of the interesting double star named Porrima or Arich (Greek lower-case letter 'gamma' Vir or Gamma Virginis, mag. +2.8). In late July 2012 Mars moved to the South of the ecliptic, then on August 6th it passed 2 South of another double star Greek lower-case letter 'theta' Vir (Theta Virginis, mag. +4.4). Finally, the Red Planet encountered Virgo's brightest star Spica (Greek lower-case letter 'alpha' Vir or Alpha Virginis, mag. +1.0), passing 1.9 to the North of it on August 13th.

On August 17th 2012, Mars passed 2.9 South of the ringed planet Saturn, in what astronomers term a planetary conjunction (for details of this and other planetary conjunctions involving Mars this apparition, see below). At magnitude +0.9, Saturn was well past its brightest at this time, having faded since reaching opposition in April 2012. Although this was potentially Mars' best planetary conjunction of 2011-13, it was only visible with ease from latitudes South of about 45 North.

As August 2012 drew to a close, Mars exited the star chart coverage, entering the constellation of Libra, the Balance (or Scales) on September 5th. As it proceeded through the Southern constellations of the zodiac, Mars' distance from Earth increased, causing its apparent size to shrink. Its phase, however, slowly increased over the same period, such that its overall magnitude remained more-or-less constant:

Date Range

Constellation

<----- Mid-Period ----->

Apparent Magnitude

Apparent

Diameter

(arcsecs)

Solar

Elongation

2012

(Aug 21) to Sep 5

Astrological symbol of Virgo

Virgo

+1.2

5".2

57E

Sep 5 to Oct 6

Astrological symbol of Libra

Libra

+1.2

4".9

50E

Oct 6 to Oct 18

Astrological symbol of Scorpius

Scorpius

+1.2

4".7

44E

Oct 18 to Nov 12

 

Ophiuchus

+1.2

4".6

39E

Nov 12 to Dec 25

Astrological symbol of Sagittarius

Sagittarius

+1.2

4".3

31E

Dec 25 to

Astrological symbol of Capricornus (Capricorn)

Capricornus

+1.2

4".2

21E

2013

 Jan 29

Jan 29 to Mar 4

Astrological symbol of Aquarius

Aquarius

+1.1

4".0

13E

Table showing the position and apparent magnitude of Mars for the latter part of the 2011-13 apparition. The magnitudes, diameters and solar elongations again refer to the middle of the period in question. After leaving Virgo, Mars continued Southwards along the ecliptical band, moving through Libra, Scorpius and Ophiuchus before reaching its most Southerly declination for this apparition (-24.5) in Sagittarius. The apparition ended a few months later, the planet having moved Northwards once more into Aquarius, where it became lost from view in the evening twilight, setting in the West shortly after sunset.

Seen from mid-Northern latitudes, Mars became increasingly difficult to view from around mid-October 2012, the planet appearing low down in the South-west after sunset. Mars attained its most Southerly declination of -24.55 (i.e. 24.55 degrees South of the celestial equator) on November 18th, when it was in the constellation of Sagittarius, the Archer. From wherever the planet was still visible, it then set at its most Southerly position along the local horizon (in the WSW from mid-Northern and Equatorial latitudes; towards the South-west in mid-Southern latitudes). Mid-Southern hemisphere latitudes began to experience difficulty viewing the planet from around mid-December 2012, when it was setting in the WSW about 2 hours after sunset. Equatorial latitudes continued to see Mars with relative ease through to about mid-January 2013, by which time the planet was positioned only 21 East of the Sun.

Mars became lost in the twilight glare from all latitudes from around mid-February 2013, when its solar elongation had reduced below 14. There then followed a prolonged period of non-visibility as the planet continued to head in an Eastward direction on the far side of its orbit from the Earth, returning to the perihelion point in its orbit on January 24th 2013, when it was 1.3814 AU (206.6 million kms / 128.4 million miles) from the Sun. Seen from the Earth, Mars passed behind the Sun - at superior conjunction - on April 18th 2013, although its most distant point from the Earth (the apogee) occurred a fortnight later on June 4th, when it was 2.4665 AU (368.9 million kms / 229.2 million miles) from the Earth and its apparent size was a mere 3".8 across.

The Red Planet became visible from the Earth again in the dawn sky from around mid-June 2013, when it was first glimpsed from Equatorial latitudes. This heralded the start of the 2013-15 apparition, which saw Mars in the constellation of Virgo when it next reached opposition in April 2014 (for details, see the Mars 2013-15 page).

 [Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]

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Mars Conjunctions with other Planets, April 2011 to February 2013

The following table lists the conjunctions involving Mars which took place at solar elongations of 15 or greater. In several cases, other planets were also in the vicinity and these are detailed. Note that, because some of the conjunctions occur in twilight, the planets involved may not have appeared as bright as their listed magnitude suggests.

Table showing Mars conjunctions with other planets from April 2011 to February 2013 (Copyright Martin J Powell, 2011)

Mars conjunctions with other planets from April 2011 to February 2013 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 Mars, e.g. on 2012 Aug 17, Saturn was positioned 2.9 North of Mars 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 45N would have found the conjunction to be difficult or impossible to view 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. perpendicular to the celestial equator) and the other is measured along the ecliptic, which is inclined at 23 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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Finding Mars in the Night Sky, September 2011 to August 2012

During the brightest period of its 2011-13 apparition, Mars was easily found using the well-known asterism known as The Big Dipper (or The Plough) in the constellation of Ursa Major, the Great Bear.

Between September and October 2011, when Mars was moving through Gemini and Cancer, the planet could be found using the method shown in the animation here. From November 2011 through to late August 2012, when Mars was moving through Leo and Virgo, observers could use the animation here.

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Bright Stars and Deep-Sky Objects

The seven brightest stars on the star chart are (in order of descending brightness):

From mid-January to late April 2012, Mars was brighter than all of the stars shown on the star chart; indeed, it was brighter than both Castor and Alphard throughout the period. The Red Planet was brighter than Procyon from mid-December 2011 to late May 2012, brighter than Spica from mid-November 2011 to mid-July 2012 and brighter than Pollux from late October 2011 to mid-August 2012. The star Regulus, which was positioned not far from Mars during much of the 2011-13 apparition, was exceeded in brightness by the planet from late September 2011 through to the end of the star chart period.

Photograph showing the constellations of Leo, Virgo and Coma Berenices. Click for a full-size photo (Copyright Martin J Powell, 2011)

 

Chart showing the areas of the 2011-12 star chart which are covered by the photographs. Dashed lines indicate that the photograph extends beyond the boundary of the star chart

Photograph showing the constellation of Cancer and the Northern region of Hydra. Click for a full-size photo (Copyright Martin J Powell, 2005)

Cancer, Northern Hydra, Leo, Virgo and Coma Berenices

Photographs showing the region of the night sky through which Mars passed from mid-2011 to mid-2014. In the Leo/Virgo photo, stars are visible down to about magnitude +7.0 and for the Cancer photo the limiting magnitude is about +8.2. Note that the two photographs do not have the same scale because of the differing camera lens settings and image resolutions (click on the images for their full-size equivalents).

Lying to both North and South of Mars' path through the zodiac from 2011-13 are numerous interesting deep-sky objects (objects beyond our Solar System) which can be seen through small telescopes and binoculars. More details can be found on the Zodiacal Sky: Cancer-Leo-Virgo page.

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Moon near Mars Dates, May 2011 to February 2013

The Moon is easy to find, and on one or two days in each month, it passes Mars in the sky. The following tables list the dates on which the Moon passed near the planet between May 2011 and February 2013:

Date Range

(World)

Conjunction (Geocentric)

Solar Elong.

Moon Phase

Date & Time

Sep. & Dir.

2011

May 1/2

May 1, 19:43 UT

5.5 S

18W

Waning Crescent

May 30/31

May 30, 20:04 UT

3.8 S

24W

Waning Crescent

Jun 28/29

Jun 28, 18:59 UT

1.7 S

31W

Waning Crescent

Jul 27/28

Jul 27, 16:53 UT

0.5 N

39W

Waning Crescent

Aug 25/26

Aug 25, 13:37 UT

2.7 N

47W

Waning Crescent

Sep 22/23

Sep 23, 08:23 UT

4.7 N

57W

Waning Crescent

Oct 21/22

Oct 21, 23:51 UT

6.5 N

69W

Waning Crescent

Nov 18/19

Nov 19, 10:14 UT

7.7 N

82W

Waning Crescent

Dec 17/18

Dec 17, 13:26 UT

8.5 N

99W

Last Quarter

Moon near Mars dates for the period from May 2011 to February 2013. The Date Range shows the range of dates worldwide (allowing for Time Zone differences across East and West hemispheres). Note that the Date, Time and Separation of 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. All times are Universal Time [UT], which is equivalent to GMT. The Sep. & Dir. column gives the angular distance (separation) and direction of the planet relative to the Moon, e.g. on August 22nd 2012 at 07:51 UT, Mars was positioned 2.3 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).

2012

Jan 13/14

Jan 14, 06:50 UT

9.1 N

121W

Waning Gibbous

Feb 9/10

Feb 10, 11:31 UT

9.7 N

150W

Waning Gibbous

Mar 7/8

Mar 8, 05:32 UT

9.8 N

172E

Full

Apr 3/4

Apr 4, 02:44 UT

8.9 N

139E

Waxing Gibbous

May 1/2

May 1, 13:32 UT

7.8 N

114E

Waxing Gibbous

May 28/29

May 29, 11:17 UT

6.9 N

95E

Waxing Gibbous

Jun 26/27

Jun 26, 15:02 UT

5.7 N

81E

Waxing Crescent

Jul 24/25

Jul 24, 22:07 UT

4.2 N

69E

Waxing Crescent

Aug 21/22

Aug 22, 07:51 UT

2.3 N

59E

Waxing Crescent

Sep 19*/20

Sep 19, 20:37 UT

0.1 N

50E

Waxing Crescent

Oct 18/19

Oct 18, 13:07 UT

2.0 S

42E

Waxing Crescent

Nov 15/16

Nov 16, 09:42 UT

4.0 S

35E

Waxing Crescent

Dec 14/15

Dec 15, 09:48 UT

5.6 S

28E

Waxing Crescent

* A lunar occultation took place (i.e. Mars disappeared from view behind the Moon), visible from the South-eastern region of South America. See the United States Naval Observatory's Astronomical Almanac 2012 for more details.

2013

Jan 12/13

Jan 13, 11:55 UT

6.4 S

21E

Waxing Crescent

Feb 11/12

Feb 11, 14:09 UT

6.1 S

14E

Waxing Crescent

The Moon moves relatively quickly against the background stars in an Eastward direction, at about its own angular width (0.5) each hour (about 12.2 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 Mars when seen from some locations than others. For this reason, the dates shown in the table should be used only for general guidance.

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The Naked-eye appearance of Mars

Naked Eye Planet Index

Planetary Movements through the Zodiac

Mercury

Venus

Mars

Jupiter

Saturn

Uranus

Neptune

Pluto


Credits


Copyright  Martin J Powell  August 2011


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