July  2010

Updated:   1 July 2010



Welcome to the night skies of Winter, featuring  Carina, Southern Cross, Centaurus, Scorpius and Saturn

  

Explanatory Notes:  

Times for transient sky phenomena are given using a 24 hour clock, i.e. 20:30 hrs = 8.30 pm. Times are in Australian Eastern Standard Time (AEST), which equals Universal Time (UT) + 10 hours. Queensland does not observe daylight saving time. Observers in other time zones will need to make their own corrections where appropriate. With conjunctions of the Moon and planets, timings indicate the closest approach. Directions (north or south) are approximate. The Moon’s diameter is given in arcminutes ( ’ ). The Moon is usually about 30’ or half a degree across. The 'limb' of the Moon is its edge as projected against the sky background.

Rise and set times are given for the theoretical horizon, which is a flat horizon all the way round the compass, with no mountains, hills, trees or buildings to obscure the view. Observers will have to make allowance for their own actual horizon. 

Transient phenomena are provided for the current month and the next. In the list of geocentric events, the nearer object is given first.

When a planet is referred to as ‘stationary’, it means that its movement across the stellar background appears to have ceased, not that the planet itself has stopped. With inferior planets (those inside the Earth’s orbit, Mercury and Venus), this is caused by the planet heading either directly towards or directly away from the Earth. With superior planets (Mars out to Pluto), this phenomenon is caused by the planet either beginning or ending its retrograde loop due to the Earth’s overtaking it.

Apogee and perigee:   Maximum and minimum distances of the Moon or artificial satellite from the Earth.

Aphelion and perihelion:  Maximum and minimum distances of a planet, asteroid or comet from the Sun.

A handspan at arm's length covers an angle of approximately 20 degrees.

mv = visual magnitude or brightness. Magnitude 1 stars are very bright, magnitude 2 less so, and magnitude 6 stars are so faint that the unaided eye can only just detect them under good, dark conditions. Binoculars will allow us to see down to magnitude 8, and the Observatory telescope can reach magnitude 15. The world's biggest telescopes have detected stars and galaxies as faint as magnitude 30. The sixteen very brightest stars are assigned magnitudes of 0 or even -1. The brightest star, Sirius, has a magnitude of -1.44. Jupiter can reach -2.4, and Venus can be more than 6 times brighter at magnitude -4.7, bright enough to cast shadows. The Full Moon can reach magnitude -12 and the Sun magnitude -27. Each magnitude step is 2.51 times brighter or fainter than the next one, i.e. a magnitude 3.0 star is 2.51 times brighter than a magnitude 4.0. Magnitude 1.0 stars are exactly 100 times brighter than magnitude 6.0 (5 steps each of 2.51 times, 2.51x2.51x2.51x2.51x2.51 = 2.515 = 100).

 

  

Solar System

 

Sun:  The Sun begins the month in the constellation of Gemini, the Twins. It passes into Cancer, the Crab on July 21.

 

Partial solar eclipse:

On the morning of July 12 next, there will be an eclipse of the Sun in which two-thirds of the Sun will be obscured. Unfortunately, the eclipse will not be visible from the Sunshine Coast, as it will end at 5:08 am, an hour and a half before sunrise.

 

Moon Phases:   Lunations this month:  #1082, 1083 

Last Quarter:        July 5                             0:36 hrs            diameter = 29.9'
New Moon:       
    July 12                           5:40 hrs            diameter = 32.9'          Partial solar eclipse
First Quarter:        July 18                         20:10 hrs            diameter = 31.8'
Full Moon:             July 26                         11:37 hrs            diameter = 29.7'

Last Quarter:        August 3                      14:59 hrs            diameter = 30.4'
New Moon:       
    August 10                    13:08 hrs            diameter = 33.4'
First Quarter:        August 17                      4:14 hrs            diameter = 31.3'
Full Moon:             August 25                      3:05 hrs            diameter = 29.4'

Lunar Orbital Elements:

July 1:                    Moon at apogee (405 063 km) at 20:10 hrs, diameter = 29.5' 
July 11:                  Moon at descending node at 17:28 hrs, diameter = 32.7' 
July 13:                  Moon at perigee (361 122 km) at 21:22 hrs, diameter = 33.1'
Jul
y 24:                  Moon at ascending node at 17:59 hrs, diameter = 30.0'
July 29:                  Moon at apogee (405 958 km) at 10:20 hrs, diameter = 29.4'

August 8:               Moon at descending node at 3:23 hrs, diameter = 32.6' 
August 11:             Moon at perigee (357 869 km) at 3:59 hrs, diameter = 33.4'
August 20:             Moon at ascending node at 22:15 hrs, diameter = 30.0'        
August 25:             Moon at apogee (406 370 km) at 15:58 hrs, diameter = 29.4'

Moon at 8 days after New, as on July 19

Moon at 9 days after New, as on July 20

The two photographs above show the Mare Imbrium area in the Moon's northern hemisphere. They were taken a day apart, just after First Quarter. Mare Imbrium (the Sea of Rains) is a large lava flow caused by the Imbrium Event - a cataclysmic collision of an asteroid with the Moon many millions of years ago. A comparison of the two photographs will show how the appearance of lunar features changes with the angle of the Sun. 

In the first photograph, Mare Imbrium (left) is separated from Mare Serenitatis (right) by two ranges of mountains, the Alps to the north and the Apennines to the south. Two large craters at upper right are Aristoteles and Eudoxus. The straight Alpine Valley may be seen cutting through the Alps. Mt Piton (height 2000 metres) is visible as a bright spot with a shadow, due south of the southern end of the Alpine Valley. Archimedes is the large crater at left. It is a walled plain 80 kilometres in diameter with a flat floor. To its right are two bowl-shaped craters, Aristillus and Autolycus.  These craters are all formed by impact with large meteors. Apollo 15 landed close by the Apennines, in a small enclosed area to the right and below Archimedes, on the picture's central vertical axis.

In the second photograph, the sunrise line (called the 'terminator') has moved to the left, revealing a large walled plain in the Alps, known as Plato. South of Plato, an isolated mountain protruding through the lava flow is called Mt Pico. Ripples in the lava, called 'wrinkle ridges', are visible. The crater at lower left is Timocharis, 42 kilometres in diameter.

A detailed map of the Moon's near side is available here. A rotatable view of the Moon, with ability to zoom in close to the surface, and giving detailed information on each feature, may be downloaded here.

Click here for a photographic animation showing the lunar phases. It also shows the Moon's wobble or libration, and how its apparent size changes as it moves from perigee to apogee each month. It takes a little while to load, but once running is very cool !

 

Geocentric Events:

July 4:               Moon 6º north of Uranus at 0:29 hrs
July 4:               Earth at perihelion at 0:31 hrs
July 4:
               Moon 7º north of Jupiter at 5:06 hrs
July 5:               Uranus at western stationary point at 23:43 hrs (diameter = 3.5")
July 8:               Moon occults some stars in the Pleiades star cluster between 18:08 and 19:21hrs (not visible from Nambour)
July 10:             Venus
1º north of the star Regulus (Alpha Leonis, mv = 1.36) at 21:48 hrs
July 11:             Moon
2.1º north of the star Mu Geminorum, (mv= 2.87) at 6:54 hrs
July 11:             Moon 
1.4º south of the star Mebsuta (Epsilon Geminorum,  mv= 3.06) at 13:59 hrs
July 13:             Moon
3.2º south of Mercury at 8:06 hrs
July 15:             Moon
4.8º south of Venus at 6:35 hrs
July 16:             Moon
4.8º south of Mars at 10:05 hrs
July 17:             Moon
7.2º south of Saturn at 1:35 hrs
July 22:             Waxing gibbous Moon occults the star  Omicron Scorpii
(mv = 4.55) between 1:07 and 2:06 hrs
July 22:             Moon
1.3º north of the star Sigma Scorpii (mv= 2.9) at 0:27 hrs
July 22:             Moon 2.3
º north of the star Antares (Alpha Scorpii, mv = 1.06) at 3:53 hrs
July 23:             Jupiter at western stationary point at 21:17 hrs
July 24:             Moon 5.6
º south of Pluto at 2:12 hrs
July 24:             Moon 
2.3º north of the star Kaus Borealis (Lambda Sagittarii, mv= 2.82) at 6:47 hrs
July 25:             Limb of Moon 21 arcminutes south of the star Pi Sagittarii
(mv= 2.88) at 2:51 hrs
July 25:             Mars 8.5 arcminutes south of the star Zavijava (Beta Virginis, m
v= 3.59 ) at 17:21 hrs
July 28:             Moon
4.7º north of Neptune at 13:09 hrs
July 31:             Moon
6.6º north of Uranus at 6:57 hrs
July 31:             Moon
7º north of Jupiter at 13:09 hrs
July 31:             Mars
1.8º south of Saturn at 16:44 hrs

August 4:          Venus 51.5 arcminutes south of the star Zavijava (Beta Virginis, m
v= 3.59 ) at 22:05 hrs
August 5:          Moon occults stars in the Pleiades star cluster between 00:41 hrs and 2:47 am
August 7:          Mercury at Greatest Elongation East (27.2
º) at 6:16 hrs (diameter = 7.6")
August 7:          Moon
1.4º north of the star  Mu Geminorum (mv= 2.87) at 17:13 hrs
August 8:          Moon 
1.7º south of the star Mebsuta (Epsilon Geminorum,  mv= 3.06) at 00:24 hrs
August 8:          Mercury at aphelion at 20:07 hrs (diameter = 7.8")
August 8:          Venus
2.7º south of Saturn at 20:40 hrs
August 12:        Moon
1.5º south of Mercury at 9:54 hrs
August 13:        Moon
4.2º south of Venus at 18:48 hrs
August 13:        Moon
5.1º south of Mars at 23:11 hrs
August 17:        Moon 27 arcminutes south of the star Dschubba (Delta Scorpii,
mv= 2.29) at 22:29 hrs
August 18:        Moon
1.9º north of the star Sigma Scorpii (mv= 2.9) at 6:06 hrs
August 18:        Moon
2.6º north of the star Antares (Alpha Scorpii, mv = 1.06) at 9:31 hrs
August 19:        Venus
1.9º south of Mars at 14:36 hrs
August 20:        Venus at Greatest Elongation East (46
º) at 2:34 hrs (diameter = 24.3")
August 20:        Moon
5º south of Pluto at 6:57 hrs
August 20:        Moon
2.2º north of the star Kaus Borealis (Lambda Sagittarii, mv= 2.82) at 12:29 hrs
August 20:        Neptune at opposition at 19:55 hrs (diameter = 2.3")
August 21:        Mercury at eastern stationary point at 6:02 hrs (diameter = 9.6")
August 21:        Moon 2 arcminutes south of the star Pi Sagittarii
(mv= 2.88) at 8:34 hrs
August 24:        Moon
4.2º north of Neptune at 17:52 hrs
August 27:        Moon
6.1º north of Uranus at 11:48 hrs
August 27:        Moon
6.7º north of Jupiter at 15:39 hrs

 

The Planets for this month: 

 

Mercury:   The innermost planet passed behind the Sun (superior conjunction) on June 28, and this month will re-appear in the evening sky, between Venus and the north-western horizon at dusk.  Mercury will be easiest to see in the first week of August.

 

Venus: The brightest planet is now dominating the twilight sky, and can be easily seen above the north-western horizon as daylight begins to fade.  The waxing crescent Moon will be close to Venus on July 14 and 15. At mid-month, the magnitude (brightness) of Venus will be -4.1 and its angular diameter will be 17 arcseconds. Its phase will be 65%.

(The coloured fringes to the first and third images below are due to refractive effects in our own atmosphere, and are not intrinsic to Venus. The planet was closer to the horizon when these images were taken than it was for the second photograph, which was taken when Venus was at its greatest elongation from the Sun).

         March, 2010                       August, 2010                          October, 2010      

Click here for a photographic animation showing the Venusian phases. Venus is always far brighter than anything else in the sky except for the Sun and Moon. Up until last December, Venus appeared as a 'Morning Star', but now it is an 'Evening Star' once again. Each of these appearances lasts about eight to nine months.

Because Venus was visible as the 'Evening Star' and as the 'Morning Star', astronomers of ancient times believed that it was two different objects. They called it Hesperus when it appeared in the evening sky and Phosphorus when it was seen before dawn. They also realised that these objects moved with respect to the so-called 'fixed stars' and so were not really stars themselves, but planets (from the Greek word for 'wanderers'). When it was finally realised that the two objects were one and the same, the two names were dropped and the Greeks applied a new name Aphrodite (Goddess of Love)  to the planet, to counter Ares (God of War). We use the Roman versions of these names, Venus and Mars, for these two planets.

 

Mars:   Mars has now been left far behind by the Earth, and this month presents a disc only 5 arcseconds in diameter. During July its magnitude is only 1.5, a little fainter than the stars Regulus and Spica, but brighter than the stars Denebola and Porrima. All four stars are not far from Mars this month. In mid-July, Mars will be about two handspans above the north-western horizon at 6 pm.

Watch Mars as it heads through Leo this month. It will across into Virgo on July 20 and will reach Saturn on July 31. They will be joined by Venus on August 5, and the crescent Moon will pass by the three planets on August 13. Mercury will also be close by.

In this image, the south polar cap of Mars is easily seen. Above it is a dark triangular area known as Syrtis Major. Dark Sinus Sabaeus runs off to the left, just south of the equator. Between the south polar cap and the equator is a large desert called Hellas. The desert to upper left is known as Aeria, and that to the north-east of Syrtis Major is called Isidis Regio.  Photograph taken in 1971.

 

Jupiter:  The giant planet is now dominating the eastern pre-dawn sky, in the constellation Pisces. At the beginning of July it rises due east a little after 11:15 pm.  Jupiter passed Uranus at an angular distance of only 26 arcminutes on June 8. It will continue to move away from Uranus until July 23, when it will cease its easterly movement and begin its retrograde loop, back towards Uranus. It will pass Uranus again, moving in the opposite direction, on September 19, when the two planets will be 48 arcminutes apart. Two days later, both planets will be at opposition.

 

Saturn:  The ringed planet is in the constellation Virgo, and passed through opposition on March 22. Saturn is still observable in July, and the Ring system is opening up once again. It appears as a bright cream-coloured object a little less than three handspans above the north-western  horizon at 7 pm on July 1.

Saturn is presently midway between the first magnitude stars Regulus and Spica, and brighter than either. It is less than two degrees from the third magnitude star Zavijava. Slow-moving Saturn passed from Leo into Virgo on September 2 last year, and will take three and a quarter years to move right across Virgo into Libra.

Saturn’s rings are always a magnificent sight, but at present they are very narrow, slowly widening. In early October 2009 a new, large ring around Saturn was discovered by the Spitzer Infrared Space Telescope. Although the new ring cannot be seen by ordinary telescopes, the familiar ring system seen in visible-light images can be detected in even the smallest telescope.

Left: Saturn showing the edge-on Ring.    Right: Over-exposed Saturn surrounded by its satellites Rhea, Enceladus, Dione, Tethys and Titan - February 23/24, 2009.

 

Uranus:  This planet reached conjunction on March 17, and at mid-month rises at about 10:15 pm. Its magnitude is 5.8 and its diameter is 4 arcseconds. Its proximity to Jupiter makes it easy to locate with binoculars.

 

Neptune:  The icy blue planet passed through conjunction on February 15, and reached western quadrature on May 20. On July 1 it rises in the constellation Aquarius a little before 9 pm. It currently nearly two handspans above Jupiter, but a telescope is needed to observe it. It reaches opposition on August 20.

Neptune, photographed from Nambour on October 31, 2008

 

Pluto:  The erstwhile ninth and most distant planet is a faint 14.1 magnitude object in the constellation Sagittarius, near the boundary with Scutum (The Shield). It is currently passing through the great Sagittarius star cloud, close to the cluster M24, and about 2 degrees south of the Omega (or Swan) Nebula, M17. A powerful telescope is needed to detect Pluto, which even under excellent seeing conditions appears as a very faint star-like object. It is now observable for all of the night, and reached opposition on June 26. Its angular diameter is 0.13 arcseconds, less than one twentieth of the size of Neptune.

  

The movement of Pluto in two days, between 13 and 15 September, 2008. Pluto is the one object that has moved.
Width of field:   200 arcseconds

 

 

Meteor Showers:  

Pegasids                   July 10                      Waning crescent Moon, 6% sunlit               ZHR = 8
                                Radiant: Near the star Markab

S Delta Aquarids       July 29                      Waning gibbous Moon, 91% sunlit              ZHR = 20
                                Radiant: Between the stars Skat and Deneb Algedi

Alpha Capricornids    July 30                      Waning gibbous Moon, 86% sunlit             ZHR = 8
                                Radiant: Near the star Algedi 

Use this  Fluxtimator  to calculate the number of meteors predicted per hour for any meteor swarm on any date, for any place in the world. 


ZHR = zenithal hourly rate (number of meteors expected to be observed at the zenith in one hour). The maximum phase of meteor showers usually occurs between 3 am and sunrise. The reason most meteors are observed in the pre-dawn hours is because at that time we are on the front of the Earth as it rushes through space at 107 000 km per hour (30 km per second). We are meeting the meteors head-on, and the speed at which they enter our atmosphere is the sum of their own speed plus ours. In the evenings, we are on the rear side of the Earth, and many meteors we see at that time are actually having to catch us up. This means that the speed at which they enter our atmosphere is less than in the morning hours, and they burn up less brilliantly.

Although most meteors are found in swarms associated with debris from comets, there are numerous 'loners', meteors travelling on solitary paths through space. When these enter our atmosphere, unannounced and at any time, they are known as 'sporadics'. Oan average clear and dark evening, an observer can expect to see about ten meteors per hour. They burn up to ash in their passage through our atmosphere. The ash slowly settles to the ground as meteoric dust. The Earth gains about 80 tonnes of such dust every day, so a percentage of the soil we walk on is actually interplanetary in origin. If a meteor survives its passage through the air and reaches the ground, it is called a 'meteorite'. One caused great alarm in Canada recently, being recorded on a camera mounted on the dashboard of a police cruiser. In the past, large meteorites (possibly comet nuclei or small asteroids) collided with the Earth and produced huge craters which still exist today. These craters are called 'astroblemes'. Two famous ones in Australia are Wolfe Creek Crater and Gosse's Bluff. The Moon and Mercury are covered with such astroblemes, and craters are also found on Venus, Mars, planetary satellites, minor planets, asteroids and even comets.

 

 

Comets

Comet Lulin

This comet, (C/2007 N3), discovered in 2007 at Lulin Observatory by a collaborative team of Taiwanese and Chinese astronomers, is now heading towards the outer Solar System, and has faded below magnitude 12.

.Comet Lulin at 11:25 pm on February 28, 2009, in Leo. The brightest star is Nu Leonis, magnitude 5.26.

The LINEAR robotic telescope operated by Lincoln Near Earth Asteroid Research is used to photograph the night skies, searching for asteroids which may be on a collision course with Earth. It has also proved very successful in discovering comets, all of which are named ‘Comet LINEAR’ after the centre's initials. This name is followed by further identifying letters and numbers. Generally though, comets are named after their discoverer, or joint discoverers. There are a number of other comet and near-Earth asteroid search programs using robotic telescopes and observatory telescopes, such as:
Catalina Sky Survey, a consortium of three co-operating surveys, one of which is the Australian Siding Springs Survey (below),
Siding Spring Survey, using the 0.5 metre Uppsala Schmidt telescope at Siding Spring Observatory, N.S.W., to search the southern skies,
LONEOS, (Lowell Observatory Near-Earth Object Search), concentrating on finding near-Earth objects which could collide with our planet,
Spacewatch, run by the Lunar and Planetary Laboratory of the University of Arizona,
Ondrejov, run by Ondrejov Observatory of the Academy of Sciences in the Czech Republic, 
Xinglong, run by Beijing Astronomical Observatory 

Nearly all of these programs are based in the northern hemisphere, leaving gaps in the coverage of the southern sky. These gaps are the areas of sky where amateur astronomers look for comets from their backyard observatories.

To find out more about current comets, including finder charts showing exact positions and magnitudes, click here. To see pictures of these comets, click here.

 

The 3.9 metre Anglo-Australian Telescope (AAT) at the Australian Astronomical Observatory near Coonabarabran, NSW

 

 

Deep Space

 

Sky Charts and Maps available on-line

There are some useful representations of the sky available here. The sky charts linked below show the sky as it appears to the unaided eye. Stars rise four minutes earlier each night, so at the end of a week the stars have gained about half an hour. After a month they have gained two hours. In other words, the stars that were positioned in the sky at 8 pm at the beginning of a month will have the same positions at 6 pm by the end of that month. After 12 months the stars have gained 12 x 2 hours = 24 hours = 1 day, so after a year the stars have returned to their original positions for the chosen time. This accounts for the slow changing of the starry sky as the seasons progress.

The following interactive sky charts are courtesy of Sky and Telescope magazine. They can simulate a view of the sky from any location on Earth at any time of day or night between the years 1600 and 2400. You can also print an all-sky map. A Java-enabled web browser is required. You will need to specify the location, date and time before the charts are generated. The accuracy of the charts will depend on your computer’s clock being set to the correct time and date. 

To produce a real-time sky chart (i.e. a chart showing the sky at the instant the chart is generated), enter the name of your nearest city and the country. You will also need to enter the approximate latitude and longitude of your observing site. For the Sunshine Coast, these are:

latitude: 26.6o South                      longitude: 153o East

Then enter your time, by scrolling down through the list of cities to "Brisbane: UT + 10 hours". Enter this one if you are located near this city, as Nambour is. The code means that Brisbane is ten hours ahead of Universal Time (UT), which is related to Greenwich Mean Time (GMT), the time observed at longitude 0o, which passes through London, England.

Click here to generate these charts.  

_____________________________________


Similar real-time charts can also be generated from another source, by following this second link:

  Click here for a different real-time sky chart.

The first, circular chart will show the full hemisphere of sky overhead. The zenith is at the centre of the circle, and the cardinal points are shown around the circumference, which marks the horizon. The chart also shows the positions of the Moon and planets at that time. As the chart is rather cluttered, click on a part of it to show that section of the sky in greater detail. Also, click on Update to make the screen concurrent with the ever-moving sky.

The stars and constellations around the horizon to an elevation of about 40o can be examined by clicking on 

View horizon at this observing site.

The view can be panned around the horizon, 45 degrees at a time. Scrolling down the screen will reveal tables showing setup and customising options, and an Ephemeris showing the positions of the Sun, Moon and planets, and whether they are visible at the time or not. These charts and data are from YourSky, produced by John Walker.

The charts above and the descriptions below assume that the observer has a good observing site with a low, flat horizon that is not too much obscured by buildings or trees. Detection of fainter sky objects is greatly assisted if the observer can avoid bright lights, or, ideally, travel to a dark sky site. On the Sunshine Coast, one merely has to travel a few kilometres west of the coastal strip to enjoy magnificent sky views. On the Blackall Range, simply avoid streetlights. Allow your eyes about 15 minutes to become dark-adapted, a little longer if you have been watching television. Small binoculars can provide some amazing views, and with a small telescope, the sky’s the limit.

 

The Eta Carinae Nebula, to the right of the Southern Cross tonight

 

 

The Stars and Constellations for this Month:

 

These descriptions of the night sky are for 8 pm on July 1 and 6 pm on July 31. They start at the western horizon.

Close to the western horizon is the second magnitude star Alphard. This is an orange star that was known by Arabs in ancient times as 'The Solitary One’, as it lies in an area of sky with no bright stars nearby. 

In the north-west, Leo the Lion is preparing to set. It will have completely disappeared by 10.30 pm. The bright star Regulus (Alpha Leonis) marks the Lion’s heart. A handspan to the right and above Regulus is Denebola, a white star marking the tip of the lion's tail. It is about 30 degrees above the north-western horizon. We see the lion upside-down from the Southern Hemisphere. Regulus is the western-most star in a pattern called 'The Sickle' (or reaping-hook). It marks the end of the Sickle's handle, with the other end of the handle, the star Eta Leonis, below and to the right. The blade of the Sickle curves around clockwise from Eta Leonis to the horizon. The Sickle forms the mane and head of the lion, when observed right-way-up. The Sickle is just touching the theoretical horizon at this time tonight.  The planet Venus passes through the stars of the Sickle in the first half of the month. Mars begins July between Leo's front and hind legs. It crosses into Virgo on July 19.

The constellation Leo, as we see it from Australia. Regulus is above centre left, and Denebola above centre right. The Sickle curves down from Regulus.

High in the north, (about 43 degrees above the horizon, and about 10 degrees west of the meridian or north-south line) we can find the fourth brightest star in the night sky, Arcturus. It is outshone only by Sirius, Canopus and Alpha Centauri. Arcturus differs from those just named, for it is an obvious orange colour, a K2 star of zero magnitude. It is a particularly beautiful star, and, as it is the brightest in the constellation of Boötes, the Herdsman, it has the alternative name of Alpha Boötis. (Boötes is pronounced 'Bo-oh-tees). Boötes is due north (culminating) at this time of night.

Arcturus

East of Boötes and above the north-north-eastern horizon is a fainter circle of fourth magnitude stars, Corona Borealis, the Northern Crown. The brightest star in the Crown is named Alphecca, and it shines at magnitude 2.3.

East of the Northern Crown is Hercules, stretching from the north-north-eastern horizon upwards. Rising in the north-east is a bright white A0 star, Vega, which is the fifth brightest star, after Arcturus. Vega is the main star in the small constellation of Lyra the Lyre, which contains the famous Ring Nebula, M 57.

The Ring Nebula was ejected from the central star in a great explosion

About fifteen degrees (a little less than a handspan) to the right of Vega can be seen Albireo, a beautiful double star with contrasting colours. It is the highest star of the Northern Cross, Cygnus.

Rising above the eastern horizon is the great main-sequence star Altair. This A7 white star is the eleventh brightest in the heavens. Altair is also known as Alpha Aquilae, as it is the brightest star in the constellation of Aquila, the Eagle. It marks the heart of the eagle, and is flanked by two lesser stars marking each wing-tip, Gamma Aquilae and Beta Aquilae. This threesome, making a short horizontal line in the east, is easy to find.

Just to the west of the zenith is the next zodiacal constellation after Leo, Virgo, the Virgin. It is a large but fairly inconspicuous constellation, but it does have one bright star, Spica, which is an ellipsoidal variable star whose brightness averages magnitude 1. This star, also known as Alpha Virginis, is a hot, blue-white star of spectral type B2. It is the sixteenth brightest star, and the rest of the constellation Virgo lies to the north-west of it. Tonight, Spica is at an altitude of 65 degrees, between the zenith and Corvus. It is roughly halfway between Arcturus and the Southern Cross. Saturn begins July near the star Zavijava, and in the first two weeks of August will be joined by Venus, Mars and the Moon, making a spectacular grouping.

A handspan west of Spica is the constellation of Corvus the Crow. Corvus is a lopsided quadrilateral of four third magnitude stars. It is about three handspans above the western horizon. Directly overhead is the faint constellation of Libra, the Scales, the brightest stars of which are two of magnitude 2.7 with exotic names, Zuben Elgenubi and Zuben Eschamali.

Moving around the horizon to a little south of east, there is a large constellation known as Capricornus, the Sea-Goat. This constellation is lacking in any bright stars, and is fairly unremarkable. 

Above Capricornus is Sagittarius the Archer, through which the Milky Way passes. Sagittarius teems with stars, glowing nebulae and dust clouds, as it is in line with the centre of our galaxy.

The Trifid Nebula, M20, in Sagittarius, is composed of a reflection nebula (blue), an emission nebula (pink), and dark lanes of dust.

Adjoining Sagittarius to the south (right), there is a beautiful curve of faint stars This is Corona Australis, the Southern Crown, and it is very elegant and delicate. The brightest star in this constellation has a magnitude of only 4.1.

Underneath Sagittarius, in the eastern end of Capricornus, lies brilliant Jupiter, but the giant planet will not rise above the eastern horizon for about another three quarters of an hour. Jupiter is brighter than any star and is only outshone in the night sky only by the Moon and Venus.

Above Sagittarius and approaching the zenith is the spectacular constellation of Scorpius, the Scorpion (see below), also very rich in objects to find with a small telescope or binoculars. This famous zodiacal constellation is like a large letter 'S', and, unlike most constellations, is easy to recognise as the shape of a scorpion. At this time of year, he has his tail down and claws raised. The brightest star in Scorpius is Antares, a red type M supergiant of magnitude 0.9. Antares is the fifteenth brightest star, and will be almost exactly overhead at 9:40 pm on July 1 (4 minutes earlier per night for succeeding nights).

The body of Scorpius is at top, with the two stars in the Sting underneath, just above the centre of the picture. The red supergiant star Antares appears close to the top left corner. The stars in the lower half of the picture are in Sagittarius. Near the lower right margin is a graceful curve of fourth magnitude stars, Corona Australis, the Southern Crown.

Between Scorpius and Corona Borealis are two large but faint constellations, Serpens, the Snake, and Ophiuchus, the Serpent Bearer.

High in the south-south-west, Crux (Southern Cross) is at an altitude of 50 degrees. Crux was in a vertical position about two hours ago (6.00 pm on July 1), but now it is has tilted over to the west so that it leans at an angle of 60 degrees to the horizontal. The two Pointers, Alpha and Beta Centauri, lie to its left and form a horizontal line. The two pointers are 8 degrees apart. Alpha is the one further away from Crux. Whereas Alpha Centauri is the nearest star system to our Sun, only 4.2 light years distant, Beta is eighty times further away. Beta Centauri must have an absolute magnitude much greater than Alpha, in order to appear nearly as bright. If the night is dark and the skies are clear, a black dust cloud known as the Coalsack can be seen just to the left of Acrux, the bottom and brightest star of the Cross. Surrounding Crux on three sides is the large constellation Centaurus, its two brightest stars being the brilliant Alpha and Beta Centauri. The rest of the constellation of Centaurus arches over Crux to its right-hand side, where it adjoins Carina and Vela

At left - the two Pointers, Alpha and Beta Centauri. Centre - Crux (Southern Cross) with the dark cloud of dust known as the Coalsack at its lower left. Right - star clusters in the Milky Way and the Eta Carinae nebula.

Just to the left of the second brightest star in the Cross (Beta Crucis) is a brilliant small star cluster known as Herschel's Jewel Box. In the centre of the cluster is a red supergiant star, which is just passing through.

Beta Crucis (left) and the Jewel Box cluster

Herschel's Jewel Box

Between Crux and the south-western horizon is a very large area of sky filled with interesting objects. This was once the constellation Argo, named by ancient Greeks for Jason’s famous ship used by the Argonauts in their quest for the Golden Fleece. The constellation Argo was found to be too large, so modern star atlases divide it into three sections - Carina (the Keel), Vela (the Sails) and Puppis (the Stern).

Below Crux and to its left is a small, fainter quadrilateral of stars, Musca, the Fly. Out of all the 88 constellations, it is the only insect. Below and to the left of Alpha Centauri is a (roughly) equilateral triangle of 4th magnitude stars. This is the constellation Triangulum Australe, the Southern Triangle.

Between Scorpius and Centaurus is an interesting constellation composed of mainly third magnitude stars, Lupus, the Wolf. Midway between Triangulum Australe and Scorpius is an asterism like a small, elongated triangle. This is Ara, the Altar.

The constellations surrounding the Southern Cross

Very close to the south-south-western horizon, the star Canopus may be glimpsed soon after darkness falls. It will have set by 8:30 pm on July 1. You will need a flat horizon in this direction. Canopus is the second-brightest star in the sky after Sirius, the Dog Star.

The path of the Milky Way between Aquila and Canopus is filled with clusters, dark clouds, glowing nebulae, multiple stars and other interesting objects. Check it out with binoculars or a telescope.

Halfway between Crux and the southern horizon is a white star of magnitude 1.7, Miaplacidus. It is the second-brightest star in the constellation Carina, after Canopus, so it has the alternative name of Beta Carinae. Half a handspan to the right of Miaplacidus is the False Cross, larger and more lopsided than the Southern Cross. The False Cross is two handspans below Crux, and is also tilted in the same way. It is about a handspan above the south-western horizon, and will have completely set by midnight. Both of these Crosses are actually more like kites in shape, for, unlike Cygnus (the Northern Cross, rising in the north-north-east just before midnight on July 1), they have no star at the intersection of the two cross arms.

Between the Southern Cross and the False Cross may be seen a glowing patch of light. This is the famous Eta Carinae nebulae, which is a remarkable sight through binoculars or a small telescope working at low magnification. A photograph of this emission nebula with dark lanes appears below. The brightest star in the nebula, Eta Carinae itself, is a peculiar unstable star which has been known to explode, becoming very bright. It last did this in 1842.

The central part of the Eta Carinae nebula, showing dark lanes, molecular clouds, and glowing clouds of fluorescing hydrogen

The Keyhole, a dark cloud obscuring part of the Eta Carinae Nebula

The Homunculus, a tiny planetary nebula ejected by the eruptive variable star, Eta Carinae

Low in the south-south-west, about 10 degrees above the horizon, the Large Magellanic Cloud (LMC) is faintly visible as a diffuse glowing patch. It is about a handspan to the left (south) of Canopus. About a handspan to the left of the LMC is the Small Magellanic Cloud (SMC), a smaller glowing patch, also close to the southern horizon. From Nambour's latitude, these two clouds never set. Each day they circle the South Celestial Pole, which is a point in our sky 26.6 degrees above the horizon's due south point. Objects in the sky that never set are called 'circumpolar'. The LMC and SMC are described below.

Between Arcturus and Denebola, and 30 degrees above the north-western horizon, is a faint Y-shaped cluster of stars called Coma Berenices, or Berenice's Hair. Most of the stars in this group have a visual magnitude of about 4.5.

The area of sky between Spica and Coma Berenices is called a 'galactic window'. Being well away from the plane of the Milky Way (which we can see passing from the west-south-western horizon through the star clusters and nebulae of Carina to Crux and Centaurus high in the south, and then through Scorpius and Sagittarius high in the east to Aquila on the east-north-eastern horizon), there are fewer stars and dust clouds to obscure our view, and we can see right out of our galaxy into the depths of inter-galactic space. A 20 cm (eight inch) telescope can see numerous galaxies in this region, nearly thirty being brighter than twelfth magnitude. A larger amateur telescope can detect hundreds more. Large telescopes equipped with sensitive cameras can detect millions of galaxies in this part of the sky.

The line of the ecliptic along which the Sun, Moon and planets travel, passes through the following constellations this month: Leo, Virgo, Libra, Scorpius, Sagittarius and Capricornus.

The aborigines had a large constellation which is visible tonight, the Emu. The Coalsack forms its head, with the faint sixth magnitude star in the Coalsack, its eye. The Emu's neck is a dark lane of dust running east through the two Pointers, to Scorpius. The whole constellation Scorpius forms the Emu's body. The Emu is sitting, waiting for its eggs to hatch. The eggs are the large star clouds of Sagittarius.

If you would like to become familiar with the constellations, we suggest that you access one of the world's best collections of constellation pictures by clicking here. To see some of the best astrophotographs taken with the giant Anglo-Australian telescope, click here.

 

 

The Milky Way

A glowing band of light crossing the sky is especially noticeable during the winter months. This glow is the light of millions of faint stars combined with that coming from glowing gas clouds called nebulae. It is concentrated along the plane of our galaxy, and this month it is seen crossing the sky, starting from the south-west in the constellation Carina, and passing through Crux, Centaurus, Lupus, Scorpius, Sagittarius and Scutum to Aquila and Lyra in the north-east.

The plane of our galaxy from Scutum (at left) through Sagittarius and Scorpius (centre) to Centaurus and Crux (right). The Eta Carinae nebula is at the right margin, below centre. The Coalsack is clearly visible, and the dark dust lanes can be seen. Taken with an ultra-wide-angle lens.

It is rewarding to scan along this band with a pair of binoculars, looking for star clusters and emission nebulae. Dust lanes along the plane of the Milky Way appear to split it in two in some parts of the sky. One of these lanes can be easily seen, starting near Alpha Centauri and heading towards Antares. At 10.00 pm in mid-July, the Milky Way crosses the zenith, almost dividing the sky in two. It runs from south-west to north-east, and the very centre of our galaxy passes directly overhead.

The centre of our galaxy. The constellations partly visible here are Sagittarius (left), Ophiuchus (above centre) and Scorpius (at right). The planet Jupiter is the bright object below centre left. This is a normal unaided-eye view, except that it reaches fainter stars than the eye can see.

  

 

The Season of the Scorpion  

The spectacular constellation of Scorpius is about 45 degrees above the eastern horizon at sundown in July. Three bright stars in a gentle curve mark his head, and another three mark his body. Of this second group of three, the centre one is a bright, red supergiant, Antares. It marks the red heart of the scorpion. This star is so large that, if it swapped places with our Sun, it would engulf the Earth and extend to the orbit of Mars. It is 604 light years away and shines at magnitude 1.06. Antares, an M type star, has a faint companion which can be seen in a good amateur telescope.

The rest of the stars run around the scorpion's tail, ending with two blue-white B type stars, Shaula (the brighter of the two) and Lesath, at the tip of the scorpion's sting. These two stars are closest to the eastern horizon tonight, and are near the bottom of the picture below. Above Lesath in the body of the scorpion is an optical double star, which can be seen as two with the unaided eye.

Scorpius, with its head at top left and tail (with sting) at lower right.

Probably the two constellations most easily recognisable (apart from Crux, the Southern Cross) are Orion the Hunter and Scorpius the Scorpion. Both are large constellations containing numerous bright stars, and are very obvious 'pictures in the sky'. Both also contain a very bright red supergiant star, Betelgeuse in Orion and Antares in Scorpius. 

The red supergiant star Antares

 

 

Some fainter constellations

Between Regulus and Alphard is the inconspicuous constellation of Sextans, the Sextant. Between Sextans and the quadrilateral of Corvus, the Crow is another faint star group, Crater, the Cup. Between the Milky Way and the southern horizon may be found the lesser-known constellations of Apus the Bird of Paradise, Chamaeleon, Pavo the Peacock, Octans the Octant, Mensa the Table, Dorado the Goldfish, Indus the Indian, Hydrus the Southern Water Snake, Pictor the Painter and Telescopium the Telescope..

 

Why are some constellations bright, while others are faint ?

Our galaxy is shaped like a flattened disc containing about 100 million stars. Our star, the Sun, with its Solar System is located about two-thirds of the distance out from the centre. When we look along the plane of the galaxy, either in towards the centre or out towards the edge, we are looking along the disc through the teeming hordes of stars, clusters, dust clouds and nebulae. In the sky, the galactic plane gives the appearance which we call the Milky Way, a brighter band of light crossing the sky. This part of the sky is very interesting to observe with binoculars or telescope. The brightest and most spectacular constellations, such as Crux, Canis Major, Orion and Scorpius are located close to the Milky Way.

If we look at ninety degrees to the plane, either straight up and out of the galaxy or straight down, we are looking through comparatively few stars and gas clouds and so can see out into deep space. These are the directions of the north and south galactic poles, and because we have a clear view in these directions to distant galaxies, these parts of the sky are called the intergalactic windows. The northern window is between the constellations Virgo and Coma Berenices, roughly between the stars Denebola and Arcturus.

This window is 50 degrees above the north-western horizon early in the evenings this month, so it's a good time for observing galaxies in the Virgo cluster. The southern window is in the constellation Sculptor, not far from the star Fomalhaut. This window will be rising well before midnight. Some of the fainter and apparently insignificant constellations are found around these windows, and their lack of bright stars, clusters and gas clouds presents us with the opportunity to look across the millions of light years of space to thousands of distant galaxies.

 

Finding the South Celestial Pole:

The South Celestial Pole is that point in the southern sky around which the stars rotate in a clockwise direction. The Earth's axis is aimed exactly at this point. For an equatorially-mounted telescope, the polar axis of the mounting also needs to be aligned exactly to this point in the sky for accurate tracking to take place.

To find this point, first locate the Southern Cross. Project a line from the top of the Cross down through its base and continue straight on towards the southern horizon for another 4 Cross lengths. This will locate the approximate spot. There is no bright star to mark the Pole, whereas in the northern hemisphere they have Polaris (the Pole Star) to mark fairly closely the North Celestial Pole.

Another way to find the South Celestial Pole from southern Queensland is to choose a time when the Southern Cross is vertical (6.00 pm on July 1), and simply locate that spot in the sky which is midway between the bottom star of the Cross (Alpha Crucis), and the theoretical southern horizon.

Interesting photographs of this area can be taken by using a camera on time exposure. Set the camera on a tripod pointing due south, and open the shutter for thirty minutes or more. The Earth's rotation will cause the stars to appear to move during the exposure, being recorded on the film as short arcs of a circle. The arcs will be different colours, like the stars are. All the arcs will have a common centre of curvature, which is the south celestial pole.

   A wide-angle view of trails around the South Celestial Pole, with Scorpius and Sagittarius at left, Crux and Centaurus at top, and Carina and False Cross at right.

Star trails between the South Celestial Pole and the southern horizon. All stars that do not pass below the horizon are circumpolar.

 

 

Double and multiple stars:

Estimates vary that between 15% and 50% of stars are single bodies like our Sun, although the latest view is that less than 25% of stars are solitary. At least 30% of stars and possibly as much as 60% of stars are in double systems, where the two stars are gravitationally linked and orbit their mutual centre of gravity. Such double stars are called binaries. The remaining 20%+ of stars are in multiple systems of three stars or more. Binaries and multiple stars are formed when a condensing Bok globule or protostar splits into two or more parts. 

Binary stars may have similar components (Alpha Centauri A and B are both stars like our Sun), or they may be completely dissimilar, as with Albireo (Beta Cygni, where a bright golden giant star is paired with a smaller bluish main sequence star).

     

 The binary stars Rigil Kent (Alpha Centauri) at left, and Beta Cygni (Albireo), at right.

     

 The binary star Rigel (Beta Orionis, left) is a large white supergiant which is 500 times brighter than its small companion, Rigel B, Yet Rigel B is itself composed or a very close pair of Sun-type stars that orbit each other in less than 10 days. In the centre of the Great Nebula in Orion (M42) is a multiple star known as the Trapezium (right). This star system has four bright white stars, two of which are binary stars with fainter red companions, giving a total of six. The hazy background is caused by the cloud of fluorescing hydrogen comprising the nebula.

Acrux, the brightest star in the Southern Cross, is also known as Alpha Crucis.  It is a close binary, circled by a third dwarf companion.

Alpha Centauri (also known as Rigil Kentaurus, Rigil Kent or Toliman) is a binary easily seen with the smallest telescope. The components are both solar-type main sequence stars, one of type G and the other, slightly cooler and fainter, of type K. Through a small telescope this star system looks like a pair of distant but bright car headlights. Alpha Centauri A and B take 80 years to complete an orbit, but a tiny third component, the 11th magnitude red dwarf Proxima Centauri, takes about 1 million years to orbit the other two. It is about one tenth of a light year from the bright pair and a little closer to us, hence its name. This makes it our nearest interstellar neighbour, with a distance of 4.3 light years. Red dwarfs are by far the most common type of star, but, being so small and faint, none is visible to the unaided eye. Because they use up so little of their energy, they are also the longest-lived of stars. The bigger a star is, the shorter its life.  

Close-up of the star field around Proxima Centauri

Knowing the orbital period of the two brightest stars A and B, we can apply Kepler’s Third Law to find the distance they are apart. This tells us that Alpha Centauri A and B are about 2700 million kilometres apart or about 2.5 light hours. This makes them a little less than the distance apart of the Sun and Uranus (the orbital period of Uranus is 84 years, that of Alpha Centauri A and B is 80 years.)

Albireo (Beta Cygni) is sometimes described poetically as a large topaz with a small blue sapphire. It is one of the sky’s most beautiful objects. The stars are of classes G and B, making a wonderful colour contrast. It lies at a distance of 410 light years, 95 times further away  than Alpha Centauri.

Binary stars may be widely spaced, as the two examples just mentioned, or so close that a telescope is struggling to separated them (Acrux, Castor, Antares, Sirius). Even closer double stars cannot be split by the telescope, but the spectroscope can disclose their true nature by revealing clues in the absorption lines in their spectra. These examples are called spectroscopic binaries. In a binary system, closer stars will have shorter periods for the stars to complete an orbit. Eta Cassiopeiae takes 480 years for the stars to circle each other. The binary with the shortest period is AM Canum Venaticorum, which takes only 17½ minutes.

Sometimes one star in a binary system will pass in front of the other one, partially blocking off its light. The total light output of the pair will be seen to vary, as regular as clockwork. These are called eclipsing binaries, and are a type of variable star, although the stars themselves usually do not vary.

 

Star Clusters

The two clusters in Taurus, the Pleiades and the Hyades, are known as Open Clusters or Galactic Clusters. The name 'open cluster' refers to the fact that the stars in the cluster are grouped together, but not as tightly as in globular clusters (see below). The stars appear to be loosely arranged, and this is partly due to the fact that the cluster is relatively close to us, i.e. within our galaxy, hence the alternate name, 'galactic cluster'. These clusters are generally formed from the condensation of gas in a nebula into stars, and some are relatively young.

The photograph below shows a typical open cluster, M7*. It lies in the constellation Scorpius, just below the scorpion's sting. It lies in the direction of our galaxy's centre. The cluster itself is the group of white stars in the centre of the field. Its distance is about 380 parsecs or 1240 light years. M7 is visible tonight.

 

Galactic Cluster M7 in Scorpius

Outside the plane of our galaxy, there is a halo of Globular Clusters. These are very old, dense clusters, containing perhaps several hundred thousand stars. These stars are closer to each other than is usual, and because of its great distance from us, a globular cluster gives the impression of a solid mass of faint stars. Many other galaxies also have a halo of globular clusters circling around them.

The largest and brightest globular cluster in the sky is NGC 5139**, also known as Omega Centauri. It has a slightly oval shape. It is an outstanding winter object, and this month it is observable all night. Shining at fourth magnitude, it is faintly visible to the unaided eye, but is easily seen with binoculars, like a light in a fog. A telescope of 20 cm aperture or better will reveal its true nature, with hundreds of faint stars giving the impression of diamond dust on a black satin background. It lies at a distance of 5 kiloparsecs, or 16 300 light years.

The globular cluster Omega Centauri

The central core of Omega Centauri

There is another remarkable globular, second only to Omega Centauri. About two degrees below and to the left of the SMC (see below), binoculars can detect a fuzzy star. A telescope will reveal this faint glow as a magnificent globular cluster, lying at a distance of 5.8 kiloparsecs. Its light has taken almost 19 000 years to reach us. This is NGC 104, commonly known as 47 Tucanae. Some regard this cluster as being more spectacular than Omega Centauri, as it is more compact, and the faint stars twinkling in its core are very beautiful. This month, 47 Tucanae is close to the southern horizon, and not clearly visible.

The globular cluster 47 Tucanae

Observers aiming their telescopes towards the SMC generally also look at the nearby 47 Tucanae, but there is another globular cluster nearby which is also worth a visit. This is NGC 362, which is less than half as bright as the other globular, but this is because it is more than twice as far away. Its distance is 12.6 kiloparsecs or 41 000 light years, so it is about one-fifth of the way from our galaxy to the SMC. Both NGC 104 and NGC 362 are always above the horizon for all parts of Australia south of the Tropic of Capricorn.

 

*     M42:This number means that the Great Nebula in Orion is No. 42 in a list of 103 astronomical objects compiled and published in 1784 by Charles Messier. Charles was interested in the discovery of new comets, and his aim was to provide a list for observers of fuzzy nebulae and clusters which could easily be reported as comets by mistake. Messier's search for comets is now just a footnote to history, but his list of 103 objects is well known to all astronomers today, and has even been extended to 110 objects.

**    NGC 5139: This number means that Omega Centauri is No. 5139 in the New General Catalogue of Non-stellar Astronomical Objects. This catalogue was first published in 1888 by J. L. E. Dreyer under the auspices of the Royal Astronomical Society, as his New General Catalogue of Nebulae and Clusters of Stars. As larger telescopes built early in the 20th century discovered fainter objects in space, and also dark, obscuring nebulae and dust clouds, the NGC was supplemented with the addition of the Index Catalogue (IC). Many non-stellar objects in the sky have therefore NGC numbers or IC numbers. For example, the famous Horsehead Nebula in Orion is catalogued as IC 434. The NGC was revised in 1973, and lists 7840 objects. 

The recent explosion of discovery in astronomy has meant that more and more catalogues are being produced, but they tend to specialise in particular types of objects, rather than being all-encompassing, as the NGC / IC try to be. Some examples are the Planetary Nebulae Catalogue (PK) which lists 1455 nebulae, the Washington Catalogue of Double Stars (WDS) which lists 12 000 binaries, the General Catalogue of Variable Stars (GCVS) which lists 28 000 variables, and the Principal Galaxy Catalogue (PGC) which lists 73 000 galaxies. The largest modern catalogue is the Hubble Guide Star Catalogue (GSC) which was assembled to support the Hubble Space Telescope's need for guide stars when photographing sky objects. The GSC contains nearly 19 million stars brighter than magnitude 15.

 

Two close galaxies

Close to the southern horizon, two faint smudges of light may be seen. These are the two Clouds of Magellan, known to astronomers as the LMC (Large Magellanic Cloud) and the SMC (Small Magellanic Cloud). The LMC is to the right of the SMC, and is noticeably larger. They lie at distances of 190 000 light years for the LMC, and 200 000 light years for the SMC. They are about 60 000 light years apart. These dwarf galaxies circle our own much larger galaxy, the Milky Way. The LMC is slightly closer, but this does not account for its larger appearance. It really is larger than the SMC, and has developed as an under-sized barred spiral galaxy.

From our latitude both Magellanic Clouds are circumpolar. This means that they are closer to the South Celestial Pole than that Pole's altitude above the horizon, so they never dip below the horizon. They never rise nor set, but are always in our sky. Of course, they are not visible in daylight, but they are there, all the same.

The Large Magellanic Cloud - the bright knot of gas to left of centre is the famous Tarantula Nebula (below)