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July 2020 in the sky – Star Safari

white and black moon with black skies and body of water photography during night time

The featured picture is not real. The Moon would look different as seen from Earth but we loved the artistic license. It’s an artistic picture. Photo by GEORGE DESIPRIS on Pexels.com

THE SCIENCE TEAM FROM Milky-Way.KIWI

Overview of the night sky

The month after the solstice here in New Zealand usually – but not always, is when we celebrate the New Year. This is also known as Matariki and is when Maori observe the heliacal rising of the star cluster Pleiades, which, in combination with a specific phase of the Moon is the signal for the New Year. 

This month is also the time when the centre of the galaxy starts closing to Zenith and the Southern Cross is high up into the sky. 

We can see Jupiter and Saturn in the night sky and Mars following close. Venus is in the morning sky, rising very close to the Pleiades. The planet will be at its maximum brightness, which is actually when Venus is a crescent on 8th of July. 

monochrome photography of mountains
Photo by Anthony Waymouth on Pexels.com

Star Safari – Instructions for looking up

Listen to our Star Safari podcast where Sam, Hari and from the Northern Hemisphere, Peter are talking about what’s in the night sky of July.

What’s the Moon up to

On 5th of July, the Moon is full. It gets very close to Jupiter and Saturn on the 6th, and very close to Mars on the 12th. The Moon is in its last quarter on the 13th. On the 17th of July, the Moon and Venus will have a close approach, and then on the 19th, it will get close to Mercury. New Moon and the best time for stargazing is on the 21st of July. You can extend that for another week, until 28th of July when the Moon is at its first quarter. 

white and black moon with black skies and body of water photography during night time
Not a real picture of the Moon and the Earth but we loved the artistic license. Photo by GEORGE DESIPRIS on Pexels.com

The centre of the Galaxy – Scorpius 

One of our most favourite constellations of all times, and probably we speak on behalf of many people for that, is Scorpius. The asterism of Scorpius, where asterism is a group of stars that makes shapes, is one of the most well recognised in the sky. If you link the brightest stars in Scorpius with a dot-to-dot then it can make a recognizable Scorpion. Scorpius is one of the 48 constellations identified by the Greek astronomer Ptolemy in the second century. It is an ancient constellation that predates the Greeks. 

Libra the Scales used to be part of Scorpius

Nearby, the constellation of Libra, as old as the scorpion, was alternatively called the claws of the Scorpion. Even today, one of the main stars in Libra is called Zubenelgenubi – which means the northern claw and the other one is Zubeneschamali, which means the Southern Claw. It is possible that the two words were similar, Zibanu – meaning scales or balance and Arabic zubānā means “scorpion’s claws”, and likely similarly in other Semitic languages: this resemblance of words may be why the Scorpion’s claws became the Scales. 

woman holding white ceramic mug

Libra the scales was part of the greater asterism of Scorpius. Photo by Anderson Miranda on Pexels.com

The Sun entered this part of the ecliptic at the autumnal equinox, when the days and nights are equal, which earned it the name of “first point of Libra”, which just like the “first point of Aries” are now just names because of the precession, they ceased to coincide with the real constellation about 1000 years ago. But maybe that’s another reason why Libra is associated with justice and equality because it was there where the Sun used to change celestial hemispheres. 

A name for Scorpius in Aotearoa is Te Matau a Maui 

Back in New Zealand, we don’t have scorpions, big or small and so here Scorpius has – in the good tradition of Maori starlore, a few names, just like any other major grouping of stars. This time of the year, Scorpius is Te Matau a Maui. According to navigator Hoturoa Barcklay Kerr this is the fishhook that drags the Milky Way down from the sky. The Maori name for the Milky Way this time of the year is The Big Fish, or te Ikaroa.

Star Safari – Planets and Zodiacal Constellations

Underneath Scorpius, the true holder of the centre of the Galaxy, Sagittarius is this year in July the host of the two gas giants Jupiter and Saturn. Of course this happens visually as with everything else, all these objects are at different distances in space. The planets, orbiting around the Sun in the same plane, seem to pass through the same sections of the sky, at different speeds. 

These stars behind the path of the planets are also known as the zodiacal constellations. They form  a band of stars 8 degrees each side of the ecliptic — an imaginary line that marks the path of the Sun in the sky. Jupiter takes 12 years to go around the Sun and so each year will be visually appearing in another zodiacal constellation. This is why the Chinese zodiac also lasts 12 years as it’s based on Jupiter. Saturn takes 29 years to go around the Sun once, so most of us will see three rotations of Saturn during our lifetimes if we are lucky.

Star Safari – The South Celestial Circle in July 

Imagine a round patch of the sky, like a pot lid, about 80 degrees diameter or 40 degrees in radius, that has the centre exactly where the extension of the South Pole in the sky is. That point in the sky, where Earth’s N-S axis intersects the Universe is called the South Celestial Pole. From this latitude, all the stars that fall inside it are called circumpolar stars, as they never set never rise but turn around in circles. The height in the sky of the South Celestial Pole is given by the latitude you are at: if you stood at the North Pole, it would be exactly underneath your feet, at Nadir. At the South Pole it will be exactly above you, at Zenith. From Wellington and Wairarapa, it will be at 41 degrees above the horizon. If you go to Dunedin, it will be at 45 degrees and if you travel to Auckland it will be 36 degrees above the horizon. 

galaxy photo during night time
Photo by Alexandra Karnasopoulos on Pexels.com

On the South Celestial Lid you will find the most famous asterisms of the South:

The Pointers – pointing to the Southern Cross, the Diamond Cross, the False Cross. At this time of the year, they are all high in the sky in the evening. 

Canopus will be on the right hand side of the south celestial circle, if you imagine a watch, it would mark 3 o’clock. At the bottom of the South Celestial Circle, Achernar will be at its lowest position in the sky marking 6 o’clock. Between Achernar and the South Celestial Pole are the Magellanic Clouds, also in the lower half of the sky.  

How to find the stars of Matariki 

As Scorpius – the Fish Hook of Maui drags the Milky Way from the sky as the night sets in, all we have to do is slide left on the wake of the Milky Way. First, we will come across the two pointer stars, that are Alpha Centauri and Beta Centauri. They are right inside the Milky Way pointing at Crux, the Southern Cross. 

Remember the big clock of the heavens? There’s a trick to know when Matariki is rising. When the Southern Cross points at 5 o’clock on the celestial lid, then Matariki – the Pleiades will surely be on the horizon, rising. We might not be able to see the stars due to mountains or hills, but rest assured it is there. How much to turn left from the Southern Cross to find it? 

We will do some star hopping to find out. That is when we hop from star to star, to find objects in the sky, a normal night in the life of a stargazer. 

Start with the Pointers and the Southern Cross and turn left

Close to the Southern Cross is the coalsack, a dark patch in the sky which is made of interstellar dust. For Maori, this dark patch is also known as the flounder, or Te Patiki. Inside the flounder you will find the Jewel Box star cluster, that is home to a few red and blue giant stars. Following the flow of the Milky Way to the left, we pass the Diamond Cross and the False Cross with their beautiful binocular objects. In the Diamond cross we will find the Southern Pleiades, right underneath it is Eta Carinae. High in the sky is Canopus the main star from the constellation Carina. 

Find Canopus and Sirius

When the Southern Cross is at 5 o’clock position on the south celestial circle, Canopus will be at 7 o’clock. Canopus is the only star we use to hop that is away from the Milky Way. Keep turning left,  and you will see blue giant Rigel coming up first from beyond the horizon. Wait another hour and more stars will come into sight. To the right of Rigel, the brightest star in the sky has popped up. Sirius is in Maori Takurua, the winter wife of the Sun. This is how people of old were explaining the fact that the Sun seems to be close to some stars at different times in the year. Sirius is the brightest star in the sky and right now is very close to the horizon. To the left of Sirius, Orion’s belt is parallel to the horizon as well. 

Turn left to see Orion’s belt parallel to the horizon and find Aldebaran

Keep in mind the distance from Sirius to Orion’s belt – in Maori called Tautoru. Look the same distance to the left of Orion’s belt, lovely named here in New Zealand The Pot, you will see Aldebaran, the red giant. Aldebaran is shining bright from about 66 light years away. Aldebaran (Taumatakuku) is visually part of the closest open star cluster to Earth, The Hyades, or Matakaheru, and it was considered one of the four pillars of heaven by the ancient Persians. The Hyades are a bit further away, at about 147 light years from Earth. 

The Pleiades will be near Venus

A fist at arm’s length away from Aldebaran you will see the Pleiades, or Matariki, which is the second closest star cluster to our solar system. In between the Pleiades and the Hyades this year, is Venus, which is really bright. Someone on our Facebook feed asked why didn’t we just say – look for the brightest object in the sky and Matariki is right next to it. We could have but then missed all this travelling along the Milky Way. 

The Maori New Year in Aotearoa

The heliacal rising of Matariki is the signal for the New Year here in Aotearoa. Heliacal rising is when a star or group of stars rise and are briefly visible just before sunrise. In ancient Egypt, it was the heliacal rising of Sirius that marked the beginning of their New Year. On the day of its heliacal rising, Sirius was seen again for the first time in the morning twilight sky after having been invisible for about 70 days (at the geographical latitude of Memphis, the ancient capital of Egypt). It would be visible just a few degrees above the Eastern horizon and disappear after about 15 minutes due to the brightening of the sky just before sunrise. 

As with any oral traditions, there are different instructions for measuring the New Year, some tribes use the blue giant star Puanga (Rigel), some others use the Tangaroa Moon or the Full Moon but the majority of tribes measure it by the sighting of Matariki and the New Moon. 

The story of creation – Matariki are the eyes of Tawhirimatea

Matariki is actually an abbreviation of ‘Ngā Mata o te Ariki’ – The Eyes of the God. The god referred to is Tāwhirimātea, god of the winds and weather. When Ranginui, the sky father, and Papatūānuku, the earth mother, were separated from their dark embrace by Tāne, Tāwhirimātea was upset. He tore out his eyes, crushed them into pieces and stuck them onto the the sky. This is why Tāwhirimātea is the blind god, feeling his way around the sky and bringing winds from different directions.

Matariki is one of the pillars of heaven that hold the sky apart from earth

After Sky Father was separated from the Earth Mother, the children put 4 pillars to keep them apart. The pillars are In the West, Rehua, the red giant, you can see the stars that come out of it curving under the weight of Ranginui. In the Northeast and East – there are 3 other pou: Matariki, Tautoru and Takurua.

Some tribes call these three pou ‘Te Waka O Rangi’ which appears under a few names such as ‘Te Waka o Tainui’ or ‘Te Waka Tapu O Takitimu’. 

The waka of Taramainuku

Te Waka O Rangi is a canoe with Matariki at the front and Tautoru (Orion’s belt) at the back, captained by Taramainuku. Te Kupenga a Taramainuku is the net of Taramainuku (Orion’s shield) and every night the asterism is in the sky, Taramainuku casts his net down to earth to gather the souls of the people who died that day. He carries them along behind his waka for 11 months and then takes them to the underworld when the asterism sets next to the Sun in mid-April. 

Towards the end of June, when the asterism is back in the morning sky, Taramainuku releases the souls of the dead into the sky to become stars. This is the origin of the saying ‘kua wheturangihia koe’/’you have now become a star’. 

The Pohutukawa tree at Cape Reinga

The spirits of the dead travel then to Cape Reinga on their journey to the afterlife to leap off the headland and climb the roots of the 800-year-old pohutukawa tree and descend to the underworld to return to their traditional homeland of Hawaiki, using the Te Ara Wairua, the ‘Spirits’ pathway’. 

The 800 years old Phohutukawa at Cape Reinga is on the list of Notable trees in New Zealand.

At Cape Reinga they depart the mainland. They turn briefly at the Three Kings Islands for one last look back towards the land, then continue their journey. The Maori New Year is observed by the sighting of the New Moon around the heliacal rising of Matariki – which happens around the winter solstice.

Please know that we cannot see Matariki with the naked eye from Wellington before approximately 20th of June, because of the mountain ridge. 

Matariki in 2020

This year, Matariki would have occurred on the 21 of June, on the day of the solstice as the New Moon occurs then. But if we observe it by Tangaroa Moon, which is the last quarter, it falls on the 13th of July. 

Matariki, The Pleiades, Image by Arnaud Mariat on Unsplash

Nga Mihi O te Tau Hou, Happy New Year from New Zealand. 

References

Rangi Mataamua, 2017, Matariki, the Star of the year

Pohutukawa Reinga https://www.doc.govt.nz/parks-and-recreation/places-to-go/northland/places/te-paki-recreation-reserve/cape-reinga-te-rerenga-wairua/heritage/