WHAT'S UP THIS MONTH - JUNE 2022

(Link to What's Up May 2022)

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THESE PAGES ARE INTENDED TO HELP YOU FIND YOUR WAY AROUND THE SKY

The chart above shows the whole night sky as it appears on 15 th June at 21:00 (9 o'clock) British Summer Time (BST). As the Earth orbits the Sun and we look out into space each night the stars will appear to have moved across the sky by a small amount. Every month Earth moves one twelfth of its circuit around the Sun, this amounts to 30 degrees each month. There are about 30 days in each month so each night the stars appear to move about 1 degree. The sky will therefore appear the same as shown on the chart above at 8 o'clock BST at the beginning of the month and at 10 o'clock BST at the end of the month. The stars also appear to move 15º (360º divided by 24) each hour from east to west, due to the Earth rotating once every 24 hours.

The centre of the chart will be the position in the sky directly overhead, called the Zenith. First we need to find some familiar objects so we can get our bearings. The Pole Star Polaris can be easily found by first finding the familiar shape of the Great Bear ‘Ursa Major' that is also sometimes called the Plough or even the Big Dipper by the Americans. Ursa Major is visible throughout the year from Britain and is always quite easy to find. This month it is located high in the North West. Look for the distinctive saucepan shape, four stars forming the bowl and three stars forming the handle. Follow an imaginary line, up from the two stars in the bowl furthest from the handle. These will point the way to Polaris which will be to the north of overhead at about 50º above the northern horizon. Polaris is the only moderately bright star in a fairly empty patch of sky. When you have found Polaris turn completely around and you will be facing south. To use this chart, position yourself looking south and hold the chart above your eyes.

There are no planets visible in the evening sky this month.

THE SOUTHERN NIGHT SKY THIS MONTH

The night sky looking south at about 21:00 BST on 15th June

The chart above shows the night sky looking south at about 22:00 BST on 15th June. West is to the right and east to the left. The point in the sky directly overhead is known as the Zenith and is shown (in red) at the upper centre of the chart. The curved brown line across the sky at the bottom is the Ecliptic or Zodiac. This is the imaginary line along which the Sun, Moon and planets appear to move across the sky. The brightest stars often appear to form a group or recognisable pattern; we call these ‘Constellations'.

Constellations through which the ecliptic passes this month are Gemini (the Twins), Cancer (the Crab), Leo (the Lion), Virgo (the Virgin), Libra (the Scales), Scorpio (the Scorpion) and Sagittarius (the Archer) just coming into view in the east.

The constellation of Gemini (the Twins) is moving over the western horizon. The two brightest stars in Gemini are Castor and Pollux that are named after mythological twins. Auriga (the Charioteer) is also moving west. The brightest star in Auriga is the brilliant white star Capella which is still visible in the west in the early evening.

To the east (left) of Gemini is the rather indistinct constellation of Cancer (the Crab). The stars of Cancer are quite faint and can be difficult to discern especially in a light polluted sky. It is worth searching out Cancer using binoculars or a small telescope to see the Open Cluster M44 Praesepe (the Beehive Cluster). M44 is older and further away than M45 (the Seven Sisters) so is fainter but still looks lovely. It has a group of stars that resemble an old straw Beehive with bees around it.

The constellation of Leo (the Lion) follows Cancer along the Ecliptic and is a very interesting constellation. It does actually look a little like a lion or the Sphinx in Egypt. Around and between Leo and the neighboring constellation of Virgo is a cluster of galaxies. Our Milky Way galaxy and our local group of galaxies are members of this larger group of galaxies called the Virgo Cluster. A medium sized telescope (150mm to 200mm) and a dark sky is required to see these faint objects.

Following Leo is the less obvious constellation of Virgo but it does have one fairly bright star called Spica. Virgo gives its name to a large cluster of Galaxies that is also spread over into the neighbouring constellations of Coma Berenices (Berenices' Hair) and into Leo.

To the north of Virgo is the bright orange coloured star called Arcturus in the constellation of Boötes. Arctaurus is a Red Giant star that is nearing the end of its ‘life' as a normal star. It has used almost all of its Hydrogen fuel and has expanded to become a Red Giant, 25 times the diameter of our Sun. At the moment it shines 115 times brighter than our Sun but it is destined to collapse and become a White Dwarf.

Higher in the south east is the constellation of Hercules (the Strong Man). Hercules has a rather distinctive distorted square shape, at its centre, called the ‘Keystone'. This is due to its resemblance to the centre stone of an arch or bridge. The jewel of Hercules is without doubt is the Great Globular Cluster, Messier 13 (M13). M13 can be found in the western (right) vertical imaginary line of the ‘Keystone'. It is just visible using a good pair of 9 x 50 binoculars. The spherical cluster, of about a million stars that can be seen using a 90mm f 10 telescope but will look even more impressive when using a larger telescope.

Just moving into the eastern sky is the Summer Triangle that will begin to dominate the Summer Sky.

 

WHERE TO FIND THE PLANETS THIS MONTH

All the planets, except Uranus and Mercury are in the early morning eastern sky.

Mercury will be at its greatest westerly elongation on 16th June .

Venus is moving back towards the Sun so it will appear to be getting smaller and will appear as a widening from crescent to its gibbous phase .

Mars is still on the other side of the Sun (so appears very small) and still appears close to the Sun so will be quite difficult to see. Mars rises at about 02:00 over 2 hours before the Sun .

Jupiter rises over the eastern horizon at about 01:30. It is bright and observable but is low over the eastern horizon before sunrise. The cloud markings will just be visible on its shimmering disc in the turbulent air.

Saturn will be very low over the eastern horizon in the brightening sky and difficult to see but will be moving into the evening sky later in the summer.

Uranus rises at about 03:00 in the early morning sky just before the Sun. Uranus will be close to Venus on 12th June so will be a little easier to find.

Neptune rises at about 01:30 so will be in the sky three hours before sunrise. It will still be difficult to see in the bright midsummer sky.

 

THE SUMMER SOLSTICE (Midsummer Day)

The Summer Solstice (Midsummer Day) 21st June

As astronomers we have a rather confusing view of the sky around us due to the tilt of Earth's axis. There are some very noticeable effects that we take for granted. The first is: how much the position of the Sun in the sky changes from summer to winter.

The chart above shows the sky at midday on Midsummer Day. The Sun appears at its highest point in the Sky on 21st June at 13:00 BST (12:00 GMT) so for the UK this is the astronomical middle of summer. The Zenith is the point directly overhead from Newbury, England and is marked as a white cross on the chart above.

The Ecliptic (white arc) is the imaginary line that represents the equator of the Solar System. The Sun, Moon and planets appear to move along this imaginary line as Earth moves around its orbit about the Sun. As the tilt of Earth's axis always points to the same direction and towards the same point in the sky, the Ecliptic appears to rise and fall from our tilted point of view on our tilted Earth.

Earth's axis of rotation is always tilted in the same direction

Another affect caused by the tilted Earth is that our sky appears to move up and down as Earth's Equator effectively moves up and down from summer to winter.

The movement of Earth's Equator

Our summer occurs when the Equator moves up to the Tropic of Cancer position or down to The Tropic of Capricorn for winter. Britain will be closest to the Equator on 21st June so the Sun will appear at its highest point in the sky at midday on 21st June, the Summer Solstice.

In the northern hemisphere the north pole of Earth's axis is tilted towards the Sun during the summer season. This gives the effect of a point on the surface such as the UK being closer to the equator of the Solar System that we call the Ecliptic. As a consequence the Sun will appear much higher in the sky during the summer.

The image below shows the how the Ecliptic appears low in the sky at on Midsummer Night when it had been high in the sky during the day. The Moon appears low in the sky during the summer nights and appears large as it rises over the horizon giving us the Harvest Moon effect.

The sky at midnight on midnight on Midsummer Day

 

THE CONSTELLATIONS OF HERCULES AND BOÖTES

 

The constellations of Hercules and Boötes

The chart above shows the constellation of Hercules and its location to the west (right) of the bright star Vega in the Summer Triangle. Hercules is the great strongman from Greek mythology. He is usually illustrated in the sky (sometimes up-side-down) as the strong man with a club held above his head. The ‘Keystone' asterism (shape) can be a little difficult to identify in a light polluted sky but easy to find again.

The jewel of Hercules is without doubt is the Great Globular Cluster, Messier 13 (M13). M13 can be found in the western (right) vertical imaginary line of the ‘Keystone'. It is just visible using a good pair of 9 x 50 binoculars. The spherical cluster, of about a million stars, can be seen using a 90mm f 10 telescope but will look even more impressive when using a larger telescope.

Messier 13 (M13) The Great Globular Cluster in Hercules

Globular clusters are thought to be the cores of small galaxies that have ventured too close to a Giant Spiral Galaxy like our Milky Way.

The outer stars of these smaller galaxies have been stripped away, by the gravity of the giant spiral. This process has left the dense cores as clusters of between 100,000 and a million stars. There are about 100 Globular Clusters in a halo around our Milky Way. There is another Globular Cluster in Hercules called M92 but it is further away and needs a telescope to see.

Messier 92 (M92) A Globular Cluster in Hercules

To the west of Hercules is the bright orange coloured star called Arctaurus in the constellation of Boötes the Herdsman. Arctaurus is the only bright star in Boötes, the other stars are fainter and form the shape of an old fashioned diamond shaped kite with Arctaurus located where the string of the tail would be attached.

Arctaurus is a Red Giant star that is slightly larger than our Sun but older 7 billion years. It has used almost all of its Hydrogen fuel and has expanded in diameter to around 25x that of our Sun. At the moment it shines 115 times brighter than our Sun but it is destined to collapse to become a White Dwarf and a Planetary Nebula. It is beautiful to look at using binocular or a small telescope.

The beautiful Red Giant Star Arctaurus in Boötes

 

THE SOLAR SYSTEM - JUNE 2022

The location of the planets at 07:30 BST on 21st JUNE 2022

The chart above shows the location of the planets along the Ecliptic in the early morning sky. The sky has been darkened to make the planets visible. The planets are: (in order as they appear before sunrise) Saturn, Neptune, Jupiter, Mars, Uranus, Venus and Mercury. The planets appear low in the sky, in the bright morning or evening sky so are not well positioned for observing.

MERCURY was at Inferior conjunction with the Sun on 22nd May. After conjunction it moved into the morning sky and is now rising just before the Sun. Mercury will be at its greatest westerly elongation on 16 th June when it will be at its apparent furthest point from the Sun.

VENUS rises about one and a half hours before the Sun climbs over the eastern horizon. It is looking very bright in the east before sunrise. It is moving back towards the Sun so it will appear to be getting smaller and will appear as a widening from crescent to its gibbous phase.

MARS is still on the other side of the Sun (so appears very small) and still appears close to the Sun so will be quite difficult to see. Mars rises at about 02:00 over 2 hours before the Sun and will not appear in the evening sky again until after September 2022.

JUPITER rises over the eastern horizon at about 01:30. It is bright and observable but is low over the eastern horizon before sunrise. The cloud markings will just be visible on its shimmering disc in the turbulent air.

SATURN is the first planet to appear over the eastern horizon so will be appearing in the morning sky soon after midnight. It will be very low over the eastern horizon in the brightening sky and difficult to see but will be moving into the evening sky later in the summer.

URANUS will not be observable this month as it was in conjunction with the Sun on 5th May. It rises at about 03:00 in the early morning sky just before the Sun. Uranus will be close to Venus on 12 th June so will be a little easier to find.

NEPTUNE rises at about 01:30 so will be in the sky three hours before sunrise. It will still be difficult to see in the bright midsummer sky and will need a telescope to appear as a small blue disc.

 

THE SUN

The Sun rises at about 04:46 BST at the beginning of the month and 04:44 by the end of the month. It sets at 21:12 at the beginning of the month and 21:20 at the end of the month.

Sunspots imaged by SOHO on 21st May

There have been a lot of very nice Sunspots and even some impressive groups of sunspots recently. Sunspots and other activity on the Sun can be followed live and day to day by visiting the SOHO website at: http://sohowww.nascom.nasa.gov/ . .

 

THE MOON PHASES DURING JUNE

First Quarter will be on 7th June

Full Moon will be on 14th June

Last Quarter will be on 21st June

New Moon will be on 29th June

 

NOCTILUCENT CLOUDS (night clouds)

An image showing Noctilucent Clouds

Every year around mid-summer the Northern Hemisphere sky-watchers can catch a glimpse of the rare and very beautiful night clouds known as: Noctilucent Clouds. These mysterious, thin veils of clouds appear to form around Earth's upper atmosphere in the mesosphere, the highest level of Earth's atmosphere. At these heights near the edge of space, around 80 kilometres up, temperatures are a bone-chilling minus 100°C and the air is a million times drier than any desert.

Diagram of Earth's atmosphere showing layers

Under these extreme conditions, water vapour freezes on to any dust particles floating in the region, seeding the ice crystals that form the tendrils and filaments of noctilucent clouds. Around dusk and dawn, the Sun is just over the northern horizon and brings the clouds to life, making them glow against twilight skies for observers further south. As the clouds are so high, they can be seen from hundreds of kilometres away. They are in sunlight high above Earth and they can be seen glowing like Mother of Pearl from over the horizon where it is midnight and dark.

Noctilucent clouds were first recorded in 1885 after a volcanic eruption on the Indonesian island of Krakatau which sent a massive ash cloud into the upper atmosphere that circled Earth for months. Spectacular red sunsets and the distinctive glowing clouds persisted for years. While such large volcanic eruptions are not all that frequent, nearly a hundred tons of meteoritic dust falls on Earth every day and this meteor smoke largely seeds the formation of noctilucent clouds.

People living in latitude areas between 50º and 70º north have the best chance of seeing noctilucent clouds. Over the last century, the unusual sight has been reported more frequently. While it is a mystery why the clouds appear to be spreading, some scientists have suggested there is a link to climate change or rocket trails.

To catch sight of this beautiful seasonal phenomenon, look toward the north when the sun is below your horizon about an hour after local sunset. You can also look for them in the mornings in the north east about an hour before local sunrise.

In the image above the noctilucent clouds can be seen glowing in the sky above the northern horizon. Normal clouds are in the dark so are seen silhouetted against the bright sky above the local northern horizon. The noctilucent clouds are so high they are still in sunlight as the Sun is just 15° below the northern horizon as seen from southern England, see the diagram below.

Diagram showing how the clouds are illuminated

 

SUN PHENOMENA TO LOOK OUT FOR

 

Sun Pillar imaged from Gibraltar by Dylan Correia

Sun pillars are beams of light that extend vertically upward from the Sun after it has set over the western horizon. They can be 5 to 10 degrees tall and sometimes even higher. They might even lengthen or brighten as you gaze at them. They are beautiful to see but for those who are not familiar with them, they can appear a little creepy and sometimes mistaken for UFO activity.

Sun pillars or light pillars form when sunlight reflects off the surfaces of millions of falling ice crystals associated with thin and high-level clouds for example, cirrostratus clouds. In the right conditions, vertical shafts of light can be seen extending upward from the Sun. These sun pillars are caused by light reflecting off hexagonal ice crystals drifting in Earth's atmosphere. The ice crystals are very small and have roughly horizontal faces so they act like millions of tiny mirrors. They are falling through Earth's atmosphere, rocking slightly from side to side.

So when is the best time to see a sun pillar and the best place to see sun pillars? It is necessary to have a clear view to the north western horizon where the Sun is setting. You will most often see sun pillars when the sun is low in the western sky just before and after sunset or low in the east just after the breaking of dawn. The sun pillar is normally brightest and most noticeable just after the Sun has set over the western horizon.

No special equipment is required to see sun pillars but if binoculars are used, to have a closer look, we must wait until the Sun has completely set below the horizon. Any camera can be used to take pictures but again it is necessary to wait until the Sun is completely below the horizon. The view of Sun pillars can be considerably enhanced when seen through Polaroid sunglasses.

A sundog in the clouds

Sundogs are what look like a bit of a rainbow appearing in misty clouds around the Sun. Most people will not notice sundogs unless they know about them. They are part of a much larger family of halos that can form around the Sun.

The full set of Sun Halos labelled

If we are very lucky we may be treated to an amazing display of Sun Halos. These mostly appear in regions of cold weather when ice crystals form in higher level clouds. It is very unusual to see the full array of halos but separate parts of the halo system appear more often.

Diagram showing a pair of sun dogs

In southern England we are sometimes treated to a display of the pair of sun dogs on each side of the Sun. It is not unusual to only see one sun dog on just one side. They can be quite faint but occasionally are quite bright.

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