ERIDANUS "The River" pronounced eh-RID-a-nas

Chart showing Eridanus

This constellation meanders from Taurus (the Bull) in the northern sky, to Hydrus in the southern sky. In mythology, Eridanus was the river into which Phaeton fell after trying to drive the chariot of his father, the Sun God. It is also said to represent a real river such as the Euphrates, or the Nile, the unknown source of which was symbolised with the disappearance of the winding train of stars below the southern horizon (as seen from the northern hemisphere) to its termination in Achernar, (pronounced AY-kuh-nar) now α Eri.

Originally Eridanus included the stars of what is now Fornax, and it stretched only as far as θ Eridani, which was then known as Achernar, from the Arabic meaning End of the River. The present name of θ Eri, Acamar, comes from Achernar. In recent times Eridanus has been extended southwards below the horizon visible to the ancient Greeks, and another star has been assigned to Achernar.

To find Eridanus, look to Rigel in Orion, and follow the meandering line of stars to Achernar. The Southern Cross points towards Achernar, and about halfway between Achernar and the Cross is due south.

Chart showing Eridanus as seen to the north at about 11 pm NZDT on January 1.

Eridanus

Constellation Sculptor Constellation Phoenix Constellation Hydrus Constellation Reticulum Constellation Horologium Constellation Caelum Constellation Fornax Constellation Dorado Constellation Cetus Constellation Puppis Constellation Pictor Constellation Mensa Constellation Volans Constellation Carina Constellation Columba Constellation Lepus Constellation Canis Major Constellation Orion Constellation Taurus

Details of some of the objects shown in the chart.

α Eridani (Achernar),(the End of the River) is a magnitude 0.5 blue-white star 85 light years away.

β Eri (Cursa), (the footstool, referring to its position under the foot of Orion) is a magnitude 2.8 blue-white star 91 light years away.

ε Eri is a magnitude 3.7 star and the most like the Sun of the nearby stars. This yellow dwarf star was one of the first stars to be sent radio signals in case there is life there. It is only 10.5 light years away, so radio signals would take this long to reach it.

θ Eri (Acamar), is a striking pair of blue-white stars of magnitudes 3.2 and 4.4, 55 light years away. The two stars are only separated by just over 8 arc-seconds, so would need a small telescope to be seen separately.

32 Eri is a beautiful double star for small telescopes, consisting of a magnitude 5 yellow star and a blue-green magnitude 6.3 companion 220 light years away. Their separation is just under 7 arc-seconds, slightly closer than the two stars forming Acamar.

ο2 Eri (also known as 40 Eridani) is a remarkable triple star 15.9 light years away. A small telescope shows that the magnitude 4.4 yellow primary, a star similar to our Sun, has a widely separated magnitude 9.6 white dwarf companion, being the most easily seen white dwarf star in the sky. The separation is about 83 arc-seconds. Bigger telescopes reveal that the white dwarf has a 11th magnitude red dwarf companion, at present about 9 arc-seconds from the white dwarf.
In addition the whole system is relatively quite close to us and has a large proper motion of just over 4 arc-seconds per year. This means the star would move a distance equal to the diameter of the Moon in "only" 450 years compared to more distan background stars.

NGC 1535 is a small 9th magnitude planetary nebula 2150 light years away, appearing in a nice field of scattered stars. While the central star cannot be seen, an OIII filter helps to find and see this dying star remnant.

Visibility

Eridanus ranges over almost 60° of declination from Archenar in the south to the equator near Cursa. Archenar is sufficiently far south for it to be always visible from New Zealand, although rather low to the south in winter evenings. In mid December, Archenar is at its highest at about 10 pm NZDT when it has an altitude of about 75°, to the south.

As is fitting for a river flowing north, Eridanus then winds its way as a narrow constellation northwards before broadening out as it approaches the equator. The equatorial portion of Eridanus precedes Rigel in Orion into the sky and is to the north later in the evening in December and soon after the sky becomes dark in January.

VIRGO, pronounced VUR-go

Chart showing the constellation.

Virgo the Virgin is the second largest constellation in the sky. Many myths are associated with this constellation, which is usually seen as a beautiful or virtuous maiden. (There are only three female figures amongst the constellations). We know the maiden as Astraea, the Roman goddess of justice, but other legends have associated Virgo with successful harvests, and so she is pictured as holding an ear of wheat (the star Spica), in her left hand and a palm leaf in her right hand. In these legends she is identified with the Greek harvest goddess emeter (the Roman Ceres) or more usually with her daughter Persephone (the Roman Prosperpine).

Virgo contains a rich cluster of galaxies which is the nearest major galaxy cluster to us. The Virgo Galaxy Cluster lies about 65 million light years away and contains about 3000 members. Virgo also contains the brightest quasar 3C 273. In an 8" telescope or bigger 3C 273 appears as a 13th magnitude star. It is estimated to lie 2000 million light years away.

To find Virgo look north early evening and find Spica.

Chart showing the constellation as seen to the north soon after 9 pm at the start of June.

Virgo and surrounding constellations

Constellation Crater Constellation Corvus Constellation Hydra Constellation Libra Constellation Scorpius Constellation Serpens Constellation Bootes Coma Berenices Constellation Leo

Some stars and interesting objects in the Constellation

α Virginis (Spica) is a magnitude 1.0 blue-white star 262 light years away. It is an eclipsing binary varying in brightness by a very small amount every 4 days.

γ Vir (Porrima, named after a Roman goddess of prophecy) is a celebrated double star 39 light years away. Together the stars shine as magnitude 2.8, but small telescopes show γ Vir as a matching pair of yellow-white stars of magnitude 3.6.

δ Vir (Auva)is a magnitude 3.4 red giant star 202 light years away.

ε (epsilon) Vir (Vindmiatrix, grape gatherer), is a magnitude 2.8 yellow giant star 102 light years away.

τ Vir consists of two unrelated stars that appear close together. This is called an optical double star. The main magnitude 4.3 star is 218 light years away. The fainter star appearing close is of magnitude 9.5.

φ Vir is a magnitude 4.8 yellow giant star 135 light years away with a magnitude 9.2 orange companion star. This is not easy to see in small telescopes because of the magnitude contrast.

θ Vir is a double star visible in small telescopes, consisting of blue-white components of magnitudes 4.4 and 8.6. In 1976, the brighter star was found to be a very close pair, by speckle interferometry. This system is 415 light years away.

M 49 (NGC 4472) is a 9th magnitude elliptical giant galaxy visible in 75 mm telescopes or larger under low power. It is one of the brightest members of the Virgo cluster of galaxies.

M 58 (NGC 4579) is a 9th magnitude spiral galaxy with a noticeably brighter core.

M 60 (NGC 4649) appears as a symmetrical round haze, rising to a bright centre. It is a 9th magnitude giant elliptical galaxy.

M 84 (NGC 4374) is an elliptical galaxy discovered in 1781 by Messier, and appears as a round bright and conspicuous haze, rising to a small diffuse nucleus. It appears in the same telescopic field as M 86.

M 86 (NGC 4406) is a Seyfert galaxy showing as a narrow spindle. Seyfert galaxies are active galaxies with a bright nucleus and thought to be related to quasars.

M 87 (NGC 4486) is a fine large round object for small telescopes. Photographs reveal a giant elliptical galaxy with many globular clusters in its halo. A straight jet proceeds from the nucleus giving intense radio emission, making this known to radio astronomers as Virgo A.

The Sombrero galaxy M 104 (NGC4594) is a beautiful spiral galaxy with a large nucleus and a dense lane of dust. It lies about 35 million light years away.

Quasar 3C 273 is the brightest known quasar with a magnitude 12.8. It is about 3.5° NE of η Vir ( Zaniah) and 4.7° NW of γ (gamma) Vir (Porrima).  The position of the quasar is RA 12h 29.1m, Dec +2° 03'.

Detailed Chart showing the star field near 3C 273.

The circle round 3C 273 has a diameter of half a degree. Stars to magnitude 13.5 are shown, with those brighter than magnitude 11 labelled, plus a few fainter ones near 3C 273.

The brightest star on the chart, magnitude 7.32 is at RA 12h 26.0m, Dec +2° 03'.   The double star near the top of the chart has a separation about 50", and is at RA 12h 31.2m, Dec +1° 20'.  The chart gives a southern hemisphere view with south at the top and east to the right.

Quasar 3C 273

Visibility

Spica in Virgo is due north in early June at about 9 pm from New Zealand. The constellation first becomes visible at 9 pm in the evening early in April. It is close to setting at 9 pm early in August.

URSA MAJOR "The Great Bear" pronounced UR-sah MAY-jer

Chart showing the constellation.

URSA MAJOR "The Great Bear", also known as the Big Dipper or the Plough is third largest constellation in size. It is an ancient and well-known star group to which the Greek astronomer Ptolemy in 150 AD assigned 27 stars. The Big Dipper or Plough figure made by the seven brightest stars is well known by every northern astronomer. References to it are found in writings dating back to the dawn of civilisation. In Europe the pattern was seen as a wagon or chariot, possibly associated with King Arthur or the Holy Roman Emperor Charlemange. Others, notably the Arabs, viewed the dipper shape not as a bear, but as a bier or coffin. Some of the stars of the Big Dipper are at similar distances from us and are moving together through space.

Ursa Major is rather low in the northern sky, and not all the constellation is visible from New Zealand. The horizon on the chart is for Auckland; residents of Invercargill may just see from Tania Borealis up.

To find Ursa Major look very low to the north under an area under Leo the Lion, between Pollux and Castor, the Twins and Arcturus. The Big Dipper would appear upside-down to us but is below the horizon.

Chart showing the constellation as seen to the north at about 10.00 pm (NZST) in mid April.

The horizon shown is for Auckland, the horizon for Invercargill goes through λ UMa.

Ursa Major.

Constellation Cancer Constellation Leo Leo Minor Constellation Gemini Constellation Lynx Constellation Hydra Coma Berenices Canes Venatici Constellation Bootes Constellation Virgo

Details of some of the objects shown in the chart.

Alula Australis, ξ Ursæ Majoris is a magnitude 4.3 yellow star.

Alula Borealis, ν UMa is a magnitude 3.5 orange star 421 light years away.
These two stars are named from the Arabic al Ula, meaning first leap of the Gazelle. Australis means south, and Borealis means north.

Tania Australis, μ UMa is a magnitude 3.06 red star 249 light years away.

Tania Borealis, λ UMa is a magnitude 3.45 blue star 134 light years away.

These two stars are named from the Arabic Ath-Thaniyah, being the "second leap" of the Gazelle. Together the stars were Al Kafzah al Thaniyah the second spring of the Gazelle.

Talitha, ι UMa is a magnitude 3.1 blue star 48 light years away. Talitha comes from the Arabic "Third leap" of the Gazelle or Ath-Thalithah.

Phecda, γ UMa and Dubhe, α UMa are two stars of the Big Dipper. Phecda just rises as seen from north Northland but not from Auckland southwards. Dubhe is below the horizon for all parts of New Zealand

Visibility

The parts of this northerly constellation which are visible from New Zealand are only above the horizon for a few hours at the most. Talitha, ι UMa, has a maximum altitude of 5° from Auckland and just rises for all the North Island. It is not visible from the South Island

The two Tania stars are to the north and highest at 9 pm in mid April in New Zealand, while the two Alula stars, in the most southerly parts of the constellation, are highest at 9 pm early in May.

VELA "The Sails" pronounced VEE-lah

Chart showing Vela.

This constellation was formerly part of the very large constellation Argo Narvis - the ship of the Jason and the Argonauts who sort the Golden Fleece, which was broken up in 1877 by Gould. Since Vela is only part of a once-larger constellation, there are no stars labelled α or β.

The stars κ and δ Velorum, in conjunction with ι and ε Carinae, form the "False Cross" that is sometimes mistaken for the real Southern Cross (Crux).

Vela lies in a part of the Milky Way rich in faint nebulosity, visible in long exposure photographs, known as the Gum Nebula, after the Australian astronomer Colin S. Gum, who drew attention to it in 1952. Near the centre of the gigantic Gum nebula lies the Vela Supernova remnant (SNR), which photographs show as a beautiful intricate network of filaments spreading over an area equal to the diameter of nearly 16 Full Moons. Within the remnant is the Vela pulsar, lying about 1500 light years away.

To find Vela look towards the zenith in the late evening sky, and look a little north of a line between the Southern Cross and Canopus.

Chart showing the constellation.

Vela constellation

Constellation Carina Constellation Hydra Constellation Antlia Constellation Pyxis Constellation Puppis Constellation Columba Constellation Pictor Constellation Dorado Constellation Reticulum Constellation Hydrus Constellation Mensa Constellation Volans Constellation Chamaeleon Constellation Musca Constellation Crux Constellation Centaurus

Details of some of the objects shown in the chart.

γ Velorum is an interesting multiple star. Binoculars or a small telescope will show that it consists of two blue-white companions of magnitudes 1.8 and 4.3. The brighter star is by far the brightest Wolf-Rayet (pronounced Volf Ray-eh) star known. These stars are a rare class with very hot surfaces that seem to be ejecting gas. There are also two wider companion stars.

δ Vel is magnitude 2.0 white star 68 light years away with a close magnitude 6.5 companion star.

λ Vel is a magnitude 2.2 yellow supergiant star 490 years away.

μ Vel is a magnitude 2.7 yellow giant star 98 light years away.

κ Vel is a magnitude 2.5 blue-white star 390 light years away.

NGC 2547 is a cluster of about 50 stars just visible to the unaided eye, but best seen in binoculars. Many stars are in chains and loops, and there are many pairs and small groups of stars, including a somewhat skew version of the Southern Cross.

IC 2391 is a bright scattered cluster of 20 stars, 850 light years away, scattered around the 4th magnitude star ο Velorum. It is visible to the unaided eye as a misty patch, but best in binoculars or small wide field telescopes.

IC 2395 is a binocular cluster of about 16 stars, 4,500 light years away. Also visible to the south is the 9th magnitude cluster NGC 2670.

NGC 2736 is a faint long narrow nebular streak in a rich star field. It is an isolated easterly filament of the Vela supernova remnant. An OIII filter helps see this object.

NGC 3132 or "Eight Burst" nebula, is a bright annular planetary nebula estimated as being 2000 light years away. Photographs show an intricate, somewhat concentric structure, as if several outbursts of gaseous material had emerged from the star. The prominent central star, is not the true star exciting the nebulous glow. This hotter star is of magnitude 16 discovered in 1976.

NGC 3201 is a globular cluster, less condensed than most. Some of the stars appear in short curved rays like jets of water from a fountain.

Visibility

The most southerly parts of Vela are circumpolar from all of New Zealand and so are visible all night. From the North Island this applies to only the extreme south of the constellation. From the extreme south of the country most of the constellation remains above the horizon at all times.

The constellation is highest about 10pm (NZDT) or 9pm (NZST) at the end of March and in April. At its highest some part of the constellation passes overhead or almost overhead from all parts of New Zealand south of Hamilton.

TUCANA: the "Toucan", pronounced TOO-kayna.

Chart showing the constellations.

This constellation near the south pole of the sky, was introduced on the star chart of Johann Bayer in 1603. It represents the Toucan, the American bird with a large beak. Its most notable features are the Small Magellanic Cloud - a nearby galaxy, and the beautiful globular cluster NGC 104.

To find Tucana, look south, about halfway up the sky. Find Achernar, (the Southern Cross points towards Achernar), and find the fuzzy appearing Small Magellanic Cloud.

Chart showing Tucana as seen in mid October soon after 10 pm NZDT.

Tucana chart

Constellation Phoenix Constellation Eridanus Constellation Hydrus Constellation Octans Constellation Pavo Constellation Horologium Constellation Indus

Some stars and interesting objects in the Constellation

α Tucanae is a magnitude 2.9 orange giant star 110 light years away.

β Tuc is a multiple star in a beautiful field. β1,2 is very bright wide pair. β3 is slightly to the south-east. All these three stars are themselves close pairs, making this a sextuple system. The two almost identical magnitude 4.5 blue-white stars β1 and β2 can be seen in binoculars or small telescopes.

δ Tuc is a beautiful bright blue-white star 250 light years away, with a 9th magnitude reddish companion, visible in small telescopes.

κ Tuc is a double star with yellow and orange components 78 light years away. The stars are magnitudes 5.1 and 7.3, so small telescope users should be able to observe them. The angle and separation are slowly diminishing, so the pair will repay periodic observations.

NGC 104 (47 Tuc) is a wonderful globular cluster, crowded with innumerable stars steadily increasing to a dense very bright centre. Distance is estimated to be 16,000 light years away. The bright globular is visible to the unaided eye as a fuzzy star (It was originally catalogued as a star in pre-telescope days); can easily be seen in binoculars; while telescopes will show a most impressive and beautiful sight. Many observers find this their best globular cluster, even more impressive than the larger omega Centauri.

NGC 362 is a beautiful globular cluster, well resolved to a bright compressed centre, appearing near the edge of the Small Magellanic Cloud, but not associated with the Cloud. Distance is around 30,000 light years away.

NGC 121 is a small remarkably elongated globular cluster, that is an outlying globular cluster of the Small Magellanic Cloud, rather than our own galaxy the Milky Way. It appears as a moderately bright, oval haze through reasonable sized telescopes.

The Small Magellanic Cloud is an irregular galaxy about 196,000 light years away, and is a genuine satellite galaxy of our galaxy - the Milky Way.
There are some attractive objects for larger apertures, including the star cluster NGC 330, which appears as a knot of very luminous stars.

NGC 346 is a giant emission nebula in a field sown with stars. This is the largest HII region in the Small Magellanic Cloud, and is easily seen through binoculars.

Visibility

Tucana is a circumpolar constellation for New Zealand and so is visible throughout the year, but will be very low (and inverted) during the evening in late autumn and winter.

Tucana remains well placed for viewing and at its highest, as the sky gets dark during November. By mid December and during January, Tucana will be getting a little lower and will be tilted on its side below Achernar soon after the sky darkens.

In the late autumn and early winter when Tucana is at its lowest in the early evening, alpha Tuc is only about 12° above the horizon from mid South Island and about 5° from Auckland. By late winter it is rising again in the early evening, now being above Achernar.