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The path of Saturn against the background stars of Leo, Virgo and Libra from September 2006 to December 2013, with positions marked on the first day of each month. The positions are colour-coded by year; a quick-glance legend is in the lower right corner (e.g. all 2009 positions are shown in yellow). Periods of invisibility (i.e. when the planet is too close to the Sun, or passes behind it) are indicated by a dashed line; hence the planet became lost from view (in the evening sky) in mid-August 2008 and became visible again (in the morning sky) in late September 2008. The chart shows the changing shape of a planet's apparent looping formation as it moves through the zodiac. Saturn crossed the plane of the ecliptic (heading Northwards) in 2004-5, when it described a zig-zag formation in Gemini; it described hybrid formations (half loop, half zig-zag) during its passage through Cancer and into Leo, where they became conventional, Northward-facing loops. 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 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 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. |
The Position of Saturn in the Night Sky, 2006 to 2013 by Martin J Powell
Having spent the period from mid-2005 to mid-2006 in the constellation of Cancer, the Crab, Saturn entered Leo, the Lion, in August 2006. Its next three looping formations took place in this constellation, spending three years there before crossing into Virgo, the Virgin, in September 2009 (to find Leo and Virgo from The Big Dipper, see the animation below). Saturn crosses the celestial equator (declination = 0°), heading Southwards, in late September 2010. It will be positioned in Virgo for a little over three years before it enters Libra, the Scales (or the Balance) in early December 2012. Six months later, in mid-May 2013, the ringed planet returns to Virgo, moving retrograde and reaching its western stationary point in July, before re-entering Libra in late August 2013.
Saturn reaches opposition to the Sun (when it is closest to the Earth and brightest in the sky for the year) every 378 days, i.e. about 13 days later in each successive year. Details of the seven Saturnian oppositions covered by the above star map are given in the table below. Around opposition, Saturn is due South at local midnight in the Northern hemisphere (due North at local midnight in the Southern hemisphere). Note how the planet's appearance changes markedly at each opposition, the ring system displaying varying tilt angles to the Earth as it orbits the Sun (for more details, see the diagram of Saturn's orbit). Like the other Solar System planets, Saturn's apparent size (its angular diameter as seen from the Earth) varies slightly at each opposition because its orbit is slightly elliptical.
The dates on which Saturn reaches superior conjunction (i.e. when it passes behind the Sun as seen from the Earth) are also shown in the table. The planet is not normally visible from the Earth for about two weeks on either side of these dates.
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Apparition Period |
Opposition Circumstances |
Superior Conjunction |
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Opposition Date |
Constellation |
Declination |
Apparent Magnitude |
Diameter (arcsecs) |
Ring Tilt |
View from Earth (North up) |
Distance (AU)* |
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Globe |
Ring |
from Earth |
from Sun |
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2006/7 |
2007 Feb 10 |
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Leo |
+15°.6 |
0.0 |
20".3 |
46".0 |
-13°.9 |
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8.2003 |
9.1869 |
2007 Aug 21 |
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2007/8 |
2008 Feb 24 |
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Leo |
+11°.3 |
+0.2 |
20".0 |
45".3 |
-8°.3 |
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8.2914 |
9.2804 |
2008 Sep 4 |
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2008/9 |
2009 Mar 8 |
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Leo |
+6°.7 |
+0.5 |
19".8 |
44".9 |
-2°.6 |
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8.3944 |
9.3865 |
2009 Sep 17 |
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2009/10 |
2010 Mar 22 |
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Virgo |
+1°.8 |
+0.5 |
19".5 |
44".2 |
+3°.1 |
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8.5038 |
9.4992 |
2010 Oct 1 |
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2010/11 |
2011 Apr 3 |
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Virgo |
-2°.9 |
+0.3 |
19".3 |
43".7 |
+8°.6 |
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8.6139 |
9.6128 |
2011 Oct 13 |
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2011/12 |
2012 Apr 15 |
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Virgo |
-7°.5 |
+0.2 |
19".1 |
43".3 |
+13°.7 |
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8.7196 |
9.7220 |
2012 Oct 25 |
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2012/13 |
2013 Apr 28 |
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Libra |
-11°.7 |
+0.1 |
18".9 |
42".8 |
+18°.1 |
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8.8162 |
9.8220 |
2013 Nov 6 |
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* 1 AU (Astronomical Unit) = 149,597,870 kms (92,955,807 statute miles) |
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Saturn opposition data for the period 2007 to 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). Note that Saturn's distance slowly increases over the period (as its heads towards aphelion), causing its angular diameter to shrink slightly year by year. The planet's apparent magnitude (brightness), after reaching a low point as the Earth passes through the ring-plane in 2009, begins to brighten once more, despite the planet's increasing distance from the Earth. This is because the rings begin opening up to view after 2009, reflecting more light back towards the Earth. The Ring Tilt (the ring plane opening angle to the Earth) is positive (+) when Saturn's Northern hemisphere is tipped towards the Earth and negative (-) when the planet's Southern hemisphere is tipped towards the Earth; the maximum value it can attain is ±27°.0. The Ring Tilt values were obtained from NASA's Saturn Ephemeris Generator 2.3. All other data was obtained from 'MegaStar', 'Redshift', 'SkyGazer Ephemeris' and 'AstroViewer' software and the Saturn images were modified by the author from NASA's Solar System Simulator v4.0. |
The rings will be fully on display again in 2017, when the planet is on the Ophiuchus/Sagittarius border and ideally placed for Southern hemisphere observers. Although it will then be near its greatest possible distance from the Earth, and at its lowest possible viewing altitude for Northern hemisphere observers, Saturn's presentation of its Northern hemisphere and ring face will nonetheless be an impressive sight. The planet will reach aphelion (its furthest orbital point from the Sun) in Sagittarius in April 2018, when it will be 10.065 Astronomical Units from the Sun (where 1 AU = 149,597,870 km or 92,955,807 statute miles). Saturn will reach its most Southerly position in the zodiac just six months later, in October 2018.
By a stroke of good luck on nature's part, Saturn's perihelion (its closest orbital point to the Sun) takes place only a short while after the planet's Southern pole is tilted at its greatest angle towards the Earth, so at these times - namely, every 29½ years - we are treated to a splendid, 'close-up' view of both the globe and the ring system when seen through Earthbound telescopes. For Northern hemisphere observers the situation is even better: whenever it is near perihelion, Saturn rides high in the sky on the Taurus/Gemini border, giving the best possible observing conditions. Saturn last passed perihelion in July 2003 and will next pass it in December 2032 (when it will be in Gemini); it will then be 9.015 AU (838 million miles or 1,348 million kms) from the Sun. The planet will reach its most Northerly point in the zodiac some six months later, in April 2033.
[Terms in yellow italics are explained in greater detail in an associated article describing planetary movements in the night sky.]
Bright Stars, Nearby Stars and Galaxies
The three brightest stars on the chart form
a large triangle in the night sky; they are Arcturus (
Boötis, magnitude -0.1), Spica (
Virginis, mag. +1.0) and Regulus (
Leonis,
mag. +1.3). They are a good guide for
finding one's way around the night sky during Northern hemisphere Spring evenings
(Southern hemisphere Autumnal evenings).
Arcturus in Boötes (pronounced 'Boe-OH-teez'), the Herdsman, is the brightest star in the Northern celestial hemisphere and the fourth brightest star in the sky. It can easily be found from the curving 'handle stars' of the Big Dipper asterism (see below). Arcturus has a noticeable orange colour to the naked eye (more evident in binoculars) since this star is a red giant; it is some 27 times larger than our Sun and is 34 light years distant (where 1 light year = 63,240 AU). The name Arcturus is ancient Greek for 'bearkeeper', since Boötes was originally depicted as a herdsman driving the big and little bears (Ursa Major and Ursa Minor) around the sky and holding the leash of Canes Venatici, the Hunting Dogs. Boötes contains numerous interesting double-stars and multiple stars.
Spica in Virgo, the Virgin, is a blue-white star some 260 light years distant. It was recently found to be an eclipsing binary star, meaning that it has a much smaller, fainter companion star orbiting around it (taking 4 days to do so). The companion star had previously eluded astronomers because the light drop caused whenever it passed in front of Spica was so small that it went undetected - until an Earth-orbiting satellite, built especially for the purpose, detected it. The name Spica is Latin for 'ear of wheat' because Virgo is usually depicted as holding a sheaf of wheat in her left hand. The constellation's association with the harvest comes from the fact that in ancient times, Spica's heliacal rising (its first appearance in the dawn sky after it had been out of view behind the Sun) took place around the commencement of harvest-time. Virgo is the second largest constellation in the night sky (covering an area of 1,294 square degrees) and it contains many hundreds of galaxies (see below).
The star Porrima or
Arich (
Virginis,
mag. +2.8) is a double-star which has been of considerable interest to telescopic
observers in recent years. It comprises two almost identical, creamy-white stars,
both of similar magnitude.
The secondary star revolves around the
primary star in a highly-elliptical orbit with a period of 169 years. For much
of the twentieth century the two stars could easily be resolved in small telescopes,
however the secondary star came very close to the primary in 2005, making it
almost impossible to split, even in large-sized telescopes. The two are now separating
once more and they will again be resolvable in small telescopes after about
2012.
Saturn is in conjunction with Porrima (i.e. it attains the same celestial longitude) on October 24th 2010, when the planet is heading Eastwards (moving direct) some 38' (38 arcminutes, where 1 arcminute = 1/60th of a degree) to the South of the star. This is a difficult conjunction to view, however, since Saturn is just 19° West of the Sun at the time, visible low in the Eastern sky at dawn; the conjunction favours Northern hemisphere observers. Saturn approaches Porrima closely again (but is not in conjunction with it) in the evening sky on June 11th 2011, when the planet is 15' to the South of the star and just two days away from reaching its Western stationary point. On this occasion, both planet and star will be easily contained within the field-of-view of a low-magnification telescopic eyepiece.
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Virgo and Corvus A photograph showing the region of the night sky which Saturn passes through during the 2009-12 observing seasons. The picture was taken from latitude 51½° North in the early morning hours of late January 2006. Virgo is seen at meridian transit (due South) and the distinctive keystone-shape of Corvus is below it in the South-South-west. Both Leo and Crater are in the South-west (only the tail-end of Leo is visible in the photo). Stars in the upper region of the photo are visible down to about magnitude +8.0. Near the horizon, distant clouds (illuminated by streetlights) block Hydra's Eastern half from view. (Move your pointer over the image to identify the constellations and click on the image for a full-size picture). |
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Leo
is perhaps the most recognisable of the zodiac constellations, and one of the
few which bears a resemblance to the animal it is supposed to represent - a crouching
Lion. The Lion's head
and 'mane' are an asterism of its six Westernmost stars commonly called
the Sickle of Leo, which is shaped like a backward question-mark [
] Leo's
brightest star Regulus is the closest bright star to the ecliptic
(the apparent path of the Sun,
which the Moon and planets follow very closely) lying about 0°.5 degrees
away from it. One consequence of this
is that the star is regularly passed by the Moon and planets, and they
sometimes pass in front of it, causing it to blink out for a period of
time (an event called an occultation).
The star was given the name Regulus by the Polish mathematician and astronomer
Nicolaus Copernicus; it is Latin for 'Little King', reflecting an ancient belief
that it was the ruler of the heavens.
At the
foot of the Lion's hind leg is the star 
Leonis (mag. +4.0) and from 2008-9 Saturn
is in conjunction
with this star on three occasions. The first conjunction occurred when Saturn
was moving direct in
early November 2008, when the planet
was just 6' North of the star; this event was visible in the morning sky. The
second took place on March 5th 2009 (Saturn
36' North of the
star) when the planet was moving retrograde
(East to West) just three days before its opposition
to the Sun.
The final conjunction takes place on July 25th 2009 (Saturn
19' North of the star) when the planet is moving direct again; this event is
visible soon after sunset and favours Southern hemisphere observers.
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Turn Left At Orion A Hundred Night Sky Objects to See in a Small Telescope - and How to Find Them Guy Consolmagno & Dan M Davis |
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Approximately
mid-way between the 'upper hind leg' stars Coxa (
Leonis, mag. +3.9) and
Leonis are a pair of galaxies about 37 million light
years away.
Messier 65 (M65
or NGC
3623, magnitude +9.5) and M66 (NGC
3627, mag.
+8.8) are positioned 20 arcminutes (0°.3)
apart and are among the brightest of
many dozens of galaxies which exist in the constellation of Leo. M65
and M66
appear relatively bright and elliptical through small telescopes, orientated
in a North-South direction. They are just discernible through binoculars in
dark, moonless skies as faint, circular hazy patches of light.
Corvus,
the Crow, is a small but distinctive keystone-shaped constellation positioned
directly to the South of Virgo.
For the telescopic user, its most interesting feature is probably the double-star
named Algorab or Algorel (
Corvi, mag. +2.9). The binary comprises third-magnitude and eighth-magnitude
stars, easily separable in small telescopes; the fainter star has sometimes been
described as purplish
in colour. Corvus'
brightest star is Minkar (
Corvi, mag. +2.6); this is one of a number of examples of constellations
whose brightest star has not been designated with the (technically correct)
Greek letter alpha (),
probably due to an error in interpretation or translation at some time in history.
Indeed, Alkhiba (or Al Chiba), which carries the designation
Corvi,
is nearly 1½ magnitudes fainter than Minkar!
Three
indistinct constellations occupy much of the remainder of the star chart. Crater,
the Cup, situated to the West of Corvus,
contains little of interest to either the naked-eye or the telescopic observer;
its brightest star Alkes (
Crateris)
is magnitude +3.5. Sextans,
the Sextant, has no stars brighter than magnitude +4.5 and city dwellers may
not be able to see it at all without optical aid. Likewise Coma
Berenices,
Berenice's Hair (named after the wife of Ptolemy III of Egypt, 3rd century BC)
has no star brighter than magnitude +4.3 but it has many faint stars visible
through binoculars, particularly in its North-western quadrant. Our Milky Way
galaxy's North Pole lies in the direction of Coma
Berenices;
the constellation itself also contains numerous faint, distant galaxies
(see below).
Finally Hydra, the Water Snake, is worthy of mention since it is the largest constellation in the sky, covering an area of 1,303 square degrees (though only two sections of it are included in the star chart). It winds its way across the sky, starting just South of Cancer (with a distinct 'snake head' asterism) and passes between no less than ten constellations before 'tailing off' just to the South of Libra. Hydra should not be confused with Hydrus, the Lesser Water Snake, a much smaller constellation which lies near the Southern Celestial Pole.
'Realm of the Galaxies'
Situated
in North-western Virgo, a
short distance to the North-west of the star 
Virginis or Vindemiatrix
(Latin for 'wine merchant'), is an area of the sky known to galaxy-hunters
as the Virgo
Galaxy Cluster.
The central region of the cluster is marked on the star chart (it is sometimes
called the Coma-Virgo
Cluster, since
it straddles the boundary with Coma
Berenices,
Berenice's Hair, to the North). Over 3,000 galaxies are contained in the cluster,
which lies at a distance of about 50 million light
years. Pioneering astronomer Edwin Hubble described the region as
'The Realm of the Nebulae' in the 1920s
and was the first to suggest that they were not true nebulae
(clouds of gas and dust)
but they were in fact galaxies far beyond our own Milky Way galaxy.
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The Sombrero Galaxy (M104) is 28 million light years distant and spans 50,000 light years across. Sir William Herschel, discoverer of Uranus, was the first person to observe the dark dust lane through a telescope. A zoomable, high-resolution photo of the galaxy taken through the Hubble Space Telescope can be seen at the Hubble Site. (Photo from Learn What's Up Messier Catalogue) |
Virgo contains more bright galaxies than any other constellation. Around thirty of them are visible in small telescopes but only a few of them are potentially within the reach of binoculars; these are shown on the star chart. However the North-western region of Virgo contains no bright stars and finding one's way around this part of the sky can be difficult, even for the experienced amateur astronomer.
M49 (NGC 4472, mag. +8.4) is the brightest of the Virgo galaxies, about 60 million light years distant. Under dark, moonless skies, binoculars reveal it as a faint, circular, fuzzy glow; telescopes will reveal its slightly elliptical shape.
M87 (NGC 4486, mag. +8.6) is situated close to Virgo's Northern border with Coma Berenices, at the centre of the Virgo Cluster. Small telescopes show it as a circular 'fuzzball' with a bright, dense core; in binoculars it can be discerned as a faint, rounded glow. This galaxy is about the same size as our own Milky Way galaxy (about 120,000 light years across) but it contains many more stars - perhaps numbering several trillion! It is a strong radio and X-ray source which has been extensively studied by astronomers.
Both M49 and M87 are classed as giant elliptical galaxies, thought to have been formed by the collision of spiral galaxies over the course of billions of years.
The most famous of the Virgo galaxies is the Sombrero Galaxy (M104 or NGC 4594), some 28 million light years distant, named after its resemblance to the Mexican hat. Situated close to the border with Corvus, the Crow, its approximate location can be found by constructing a right-angle between the stars Spica and Porrima. Long-exposure photographs taken through larger telescopes show an impressive galaxy positioned nearly edge-on to our line of sight, with an equatorial dust lane orientated East-West cutting across its central, bulging core. Small and medium-sized telescopes are required to see this feature; binoculars will only discern its central core as a small, faint, ghostly glow.
The difficulty in viewing galaxies and nebulae through binoculars and small telescopes demonstrates an important point regarding the quoted apparent magnitudes of such deep sky objects. The apparent magnitude of the Sombrero Galaxy is normally listed in astronomical catalogues at around +8.5 - potentially within easy reach of most binoculars - however this is a somewhat misleading figure because it refers to the magnitude the galaxy would have if it were a single point of light (i.e. like a star). In reality a galaxy is an extended object (the Sombrero Galaxy is about 9' across and 4' high). As well as the apparent magnitude, some authors, when giving brightness values for objects such as galaxies and nebulae, also include the object's surface brightness, i.e. its apparent magnitude allowing for the fact that it is spread over an area of the sky (this is usually the magnitude per square arcminute). The surface brightness of the Sombrero Galaxy works out at about magnitude +12, which more accurately reflects its faintness in the sky - and explains why it is such a difficult object to see. Consequently, observers should not be disappointed if they fail to spot it, or any of the other galaxies mentioned above.
Finding Leo and Virgo from The Big Dipper The well-known asterism (star group) known as The Big Dipper (or The Plough) in Ursa Major (The Great Bear) can be used as a starting point to finding Leo and Virgo in the night sky (provided these constellations are above the observer's horizon at the required time). To
find Leo,
use 'The
Pointer Stars'
Dubhe
(pronounced 'DUB-ee', To
find Virgo,
use the 'handle stars' of The
Dipper (the
'handle' of The
Saucepan)
to
project an arc in a Southward direction until you come across the
bright, orange-coloured star Arcturus
( From
Arcturus,
continue
the arc Southwards to the bright star Spica
(pronounced 'SPY-kah', or Note that this method primarily applies to Northern hemisphere observers. Southern hemisphere observers can only use this method if they are situated North of latitude 28° South (The Big Dipper is not wholly visible at latitudes further South than this). Observers at mid-Southern latitudes should instead use the AstroViewer Java applet below. A diagram showing the lines pointing to Leo and Virgo from The Big Dipper can be seen here. |
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Moon near Saturn Dates, January to December 2009
On one or two days in each month, the Moon can be used as our celestial guide to help in locating Saturn in the sky. Use the following table to determine on which dates to see the Moon in the vicinity of the planet:
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Moon near Saturn dates for the period from January to December 2009 (no information is given for September because Saturn is too near the Sun at this time). 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 celestial longitude) are measured from the Earth's centre (geocentric) and not from the Earth's surface (times are given in 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 4th at 11:21 UT, Saturn is 6°.1 North of the Moon's centre. The Moon Phase shows whether the Moon is 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). |
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The Moon moves relatively quickly against the background stars (in an Eastward direction, at about its own angular width [0º.5] each hour, or about 12º.2 per day) and 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 appear closer to Saturn when seen from some locations than from others. For this reason, the dates shown in the table should be used only for general guidance.
Position of Saturn's Five Brightest Moons
Saturn's five brightest moons (satellites) - namely Titan (magnitude +8.3 at opposition), Rhea (+9.7), Tethys (+10.2), Dione (+10.4) and Enceladus (+11.7) - can readily be seen through telescopes, but only Titan (Saturn's largest moon) is visible through binoculars. The moons are seen to change their position in relation to each other from one night to the next.
Because of Saturn's relatively high axial tilt (26º.7 to the plane of its orbit) the Saturnian moons are mostly seen to follow apparent elliptical paths around the planet when viewed from the Earth (this is in contrast to, say, Jupiter's shallow axial tilt (3º.1), which causes its moons to present a more-or-less linear motion when seen from the Earth - see Jupiter's moon positions). However, the motion of Saturn's moons does appear more-or-less linear whenever the Earth crosses through the ring-plane of the planet, such as in 2009. For about a year on either side of the ring-plane crossing date, transits (when a moon or its shadow passes across the planet's disk), occultations (when a moon passes behind the planet's disk) and eclipses (when a moon enters the planet's shadow) can be observed through telescopes.
The following Flash program initialises displaying the positions of the moons at the current Universal Time (UT, which is equivalent to GMT) based on your computer's clock and Time Zone settings:
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The Positions of Saturn's five brightest satellites in relation to the planet (the graphic requires the Adobe Flash Player plug-in to display correctly). Binocular and terrestrial telescope users in the Northern hemisphere should use the default 'Erect Image' (North up, East to the left) setting; Southern hemisphere observers using this equipment will need to click on the 'Inverted' (North down, West to the left) button. Users of astronomical telescopes in the Northern hemisphere will need to use the 'Inverted' option to match the view in their telescope, whilst those in the Southern hemisphere should use the default ('Erect Image') setting. The 'Mirror Reversed' button applies to astronomical telescopes with a star diagonal attached. Enter the required values for Date (in the form mm/dd/yyyy) and Time and click on 'Recalculate' to see the position of the moons for any date and time between January 1st 1900 AD and December 31, 2100 AD. The Timezone offset from UT is determined by the settings in your web browser. Times of all events in the program are given in Universal Time (UT) which is equivalent to Greenwich Mean Time (GMT). The 'Saturn's Moons' program by John Bartucci is available as a standalone, executable (exe) file which can be downloaded from the The Wilderness Center Astronomy Club website. |
|
Saturn and How to Observe It (Astronomers' Observing Guide) Julius L. Benton, Jr. |
Saturn: The Complete Guide by Garry E. Hunt & Patrick Moore "A complete guide to Saturn and our current understanding of it" |
NightWatch: A Practical Guide to Viewing the Universe Terence Dickinson "The best handbook for the beginning astronomer" |
The 100 Best Astrophotography Targets (Patrick Moore's Practical Astronomy Series) Ruben Kier |
Night Sky A Field Guide to the Constellations Jonathan Poppele |
The New Space Race: China vs. USA (Springer Praxis Books / Space Exploration) Erik Seedhouse |
Mysteries of Galaxy Formation (Springer Praxis Books / Popular Astronomy) Françoise Combes |
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Finding Saturn in Your Local Night Sky
Where in the night sky should I look for Saturn tonight? In which direction and how high up will it be?
Through to 2013, when it is positioned in Leo or Virgo, Northern hemisphere observers can easily find Saturn using The Big Dipper (or The Plough) asterism as a starting point; for details, see the animation above.
The location of a planet (or any other celestial body) in your local night sky depends upon several factors: the constellation in which it is positioned, your geographical latitude and longitude, the local season and the date and time at which you observe. To find a planet in the night sky at any particular date and time, we must know two things: a direction in which to look along the observer's horizon (eg. Southeast, East-Southeast) and an angle to look above the horizon (known as altitude or elevation).
The following Javascript program can be used to help find Saturn (and any other planets) in your night sky throughout the year:
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For additional information on the fully-functional version of the program, see here. |
Mini-AstroViewer® is an easy-to-use Java applet which shows the positions of the celestial bodies in the night sky for any location on the globe at any time of the year (Javascript must be enabled in your browser for the program to function). To activate the program, click on the button below (the program will open in a pop-up window). The default location is New York, USA. To select your own location and then find Saturn, refer to the 'Finding Saturn ..' box below. An animated tutorial showing how to locate a planet in the night sky using Mini-AstroViewer® can be seen here.
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Finding Saturn in Your Own Night Sky using Mini-AstroViewer®
To set your own location, click on the 'Location' button and click on your approximate position on the pop-up world map. If you know your precise latitude and longitude, you can refine your position by pressing the left/right and up/down arrows to move the cross-hair in 1° increments (to find your latitude and longitude, visit the Heavens Above website, select your country and enter the name of your nearest town or city using the 'Town Search' facility). Having plotted your geographical co-ordinates, click 'OK' and the night sky over your own location will appear in the window, valid for the current time, which is displayed in UT (Universal Time, equivalent to GMT). The applet will initialise displaying the current UT time according to your browser's clock and Time Zone settings (if you would prefer to have the Local Time displayed, use the fully-functional version of the program at Astroviewer.com). The red circle represents the horizon around you; the lower half of the display represents the part of the sky you are facing. The centre of the circle is the point directly above your head (known as the zenith). The ecliptic (the path along which the Sun, Moon and planets will be found) is marked by a red dashed line, passing as it does through the zodiac constellations. The blue dashed line marks the apparent position of the celestial equator, which arcs across the sky from the due East point on the horizon to the due West point. The program plots stars down to magnitude +5.0. The bottom scroll bar rotates the horizon view, allowing for a view in any compass direction; the left-hand scroll bar zooms the sky in or out, and the right-hand scroll bar pans up (to the zenith) or down (to the horizon) whenever the view has been zoomed.
Infomation on a celestial body can be viewed by clicking on the object (in the case of a planet, its magnitude, distance, elongation and apparent diameter). Note that if the elongation (its angular distance from the Sun as seen from the Earth) is less than about 15°, the planet will not be visible because it is too near the Sun. Remember that local twilight can affect the visibility of a particular planet, even at elongations greater than 15°, making observation difficult or even impossible. This particularly applies throughout the local summer months at higher latitudes. To locate Saturn, first see if it is above the horizon at the time you are requesting. If it is visible within the circle, move the bottom scroll bar left or or right to rotate the image until the planet is positioned on the vertical red line (the altitude scale). Zoom in to the area using the left-hand scroll bar where necessary (see animation opposite). The direction of Saturn at the requested time will be indicated at the bottom (W, SW, etc). The altitude of the planet (its angle above the horizon) can be read off on the altitude scale (it is marked at 10° intervals). Hence if it is three notches up, its altitude is 30° at the displayed time (to understand how to determine a planet's altitude in the night sky, refer to the two diagrams below). If Saturn's altitude is less than about 10° it may be difficult to see because of the dimming effect of the Earth's atmosphere and, in town and city locations, the effects of light pollution or skyglow. If
Saturn is not shown within the circle, it is below the horizon
and you will have to wait until after it next rises before you can see
it (provided it is not too near the Sun). To find when it next rises,
click the 'hours forward' button ( If Saturn rises in daylight (i.e. if the Sun is already above the horizon), you will have to wait until dusk to see it - in which case, 'fast forward' to a time shortly after sunset, then note down the time and direction. The same method can also be used to find any of the visible constellations in your night sky.
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The Current Night Sky over Sacramento,
California, USA |
Would you like to see your own town or city shown here?
Requested locations may appear on another planet page (see links below) depending upon the number of requests received by the author at any given time. A list of the night sky locations currently displayed on this website can be seen on the main Naked-eye planets page. The graphic shows the sky at the location indicated when this page was loaded in your browser; if several minutes have since passed, click the 'Refresh' button at the top of your browser (or press the F5 key) to see the current sky. The Night Sky location displayed here is periodically changed by the website author. Additional AstroViewer® Information Mini-AstroViewer® is a lightweight version of AstroViewer®, an interactive night sky map that helps you find your way in the night sky quickly and easily. Due to its intuitive interface, it is well suited to beginners in astronomy. The fully functional, free-to-use version can be accessed at the AstroViewer® website. It has additional features such as a Local Time display, a planet visibility chart for any selected location, a 3D Solar System map, the ability to store user-generated world locations, a 'Find Celestial Body' facility, printing and language options and greater flexibility in the night sky display (see details here). A fully-functional version for offline use can be obtained upon the purchase of a license key, following the download and installation of a test version. AstroViewer® is produced by Dirk Matussek. |
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Positions of the Superior Planets:
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Mars, 2009-2010 |
Jupiter, 2009-2011 |
Uranus, 2006-2018 |
Neptune, 2006-2023 |
Pluto, 2006-2022 |
Current Position of the Sun and the Brighter Naked-Eye Planets (Star Map)
Credits
.Copyright © Martin J. Powell, April 2009, June 2009
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) repeatedly until the planet
appears over the eastern horizon, then note down the time and direction
this occurs. By clicking the 'minutes/hours forward' buttons (
