WHAT'S UP THIS MONTH - NOVEMBER 2021

(Link to What's Up December 2021)

(Link to What's Up October 2021)

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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 15th November at 21:00 (10 o'clock) Greenwich Mean Time (GMT). 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 GMT at the beginning of the month and at 10 o'clock GMT 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 just above the Northern horizon. 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.

Planets observable in the evening sky: Venus early evening with Saturn, Jupiter, Neptune and Uranus later.

THE SOUTHERN NIGHT SKY THIS MONTH

The night sky looking south at about 22:00 GMT on 15th November

The chart above shows the night sky looking south at about 22:00 BST on 15th November. 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: Sagittarius (the Archer), Capricornus (the Goat), Aquarius (the Water Carrier), Pisces (the Fishes), Aries (the Ram) and Taurus (the Bull).

Prominent in the southern sky is the Summer Triangle that dominates the Summer Sky and was described in detail previous pages. The triangle is defined by three obvious bright stars: Deneb in the constellation of Cygnus, Vega in Lyra, and Altair in Aquila. The Milky Way (our Galaxy) flows through the Summer Triangle and passes through Aquila and Cygnus. The Summer Triangle is bigger than may be expected but once it has been found it is very easy to find again.

To the west (right) of the Summer Triangle and almost overhead is the constellation of Hercules (the Strong Man). Hercules has a 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 the Great Globular Cluster, Messier 13 (M13) that can be found in the western vertical imaginary line forming 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.

To the west of Hercules and close to the western horizon is the bright orange coloured star called Arcturus in the constellation of Boötes. Arctaurus is a star similar to our Sun but more advanced and is developing into 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 and Planetary Nebula.

To the East of the Summer Triangle is the constellation of Pegasus (the Winged Horse). The main feature of Pegasus is the square formed by the four brightest stars. This asterism (shape) is known as the Great Square of Pegasus. The square is larger than might be expected but once found is easier to find again . There is a very nice Globular cluster in Pegasus it is known as Messier 15 (M15). It is a lovely sight to see in a telescope.

Coming into view in the south east is the constellation of Taurus (the Bull). The most obvious star in Taurus is the lovely Red Giant Star called Aldebaran. It appears slightly orange to the ‘naked eye' but it is very obviously orange when seen using binoculars or a telescope. Aldebaran is located at the centre of the ‘flattened' X shape formed by the brightest stars in Taurus. At the end of the top right (upper west) arm of the ‘X' is the beautiful ‘naked eye' Open Star Cluster Messier 45 (M45) known as the Pleiades (or the Seven Sisters). It really does look magnificent using binoculars.

The Ecliptic is low in the sky during the summer months so the Moon and planets appear close to the southern horizon. Saturn and Jupiter are well placed but due to their low altitude will not be at their best for observation this year. The thick, murky and turbulent air will cause the planets to appear quite unsteady.

Where to find the planets this month.

Mercury is not well placed this month.

Venus is visible in the early evening in the west but it is very low and close to the horizon.

Mars is too close to the Sun and is not observable.

Jupiter is very bright in the south but moving towards the west during the evening

Saturn is located to the west and slightly lower than Jupiter but is a lot fainter but easy to find.

Uranus can be found in the south east in the early evening but really needs a telescope.

Neptune is located to the east of Jupiter but will need a telescope to see it.

THE LEONID METEOR SHOWER – November 17th and 18th

The Radiant of the Leonid Meteor Shower at its peak at 01:00 on 18th November

Meteor showers are notoriously unpredictable. The exact time of any spectacular increase in numbers or if the meteors will be bright is as difficult to predict as is the clear weather needed to see them. However every year on the evening of the 17th and morning of 18th November there is usually a spectacular display from the peak of activity during the Leonid Meteor Shower.

Unfortunately this year the almost Full Moon will be a in the southern sky so some of the fainter meteors may not be seen. The meteors of a shower appear to radiate from a point in the sky that is called the ‘Radiant'. The meteors of this particular shower appear to originate from a ‘Radiant' point in the constellation of Leo. See the chart above.

The radiant point of the Leonid Meteor Shower is shown close to the star Algieba in the backward ‘?' shape of the Lion's head. The paths of the meteors are shown by the straight lines emanating from the direction of the radiant point. The meteors are small specks of dust debris from the Comet Temple Tuttle entering our atmosphere at very high speed.

During the evening of 17th November the constellation of Leo will be below the eastern horizon so any Leonid meteors will appear to originate from over the horizon. Leo will rise over the eastern horizon at about midnight. This means all the meteors will initially be moving up from the eastern horizon and in a ‘fan' shape across the sky. Leonid meteors tend to be fast and relatively bright so look anywhere from the eastern horizon to overhead.

If the trail of any meteor that is seen can be tracked back and found to have originated from this radiant point it will be a Leonid Meteor. A few meteors might appear to originate from other directions so these are the meteors that might be seen randomly and not part of any named shower. These are known as Sporadic Meteors.

Make sure you are dressed warmly with a hat and gloves and sitting comfortably. A garden lounger chair will allow the observer to lay back and have their head supported to avoid getting a neck ache from looking up.

On any clear night if you sit back and look up into the night sky for a while you will more than likely see a streak of light speed across the sky - this will be a METEOR or shooting star. It is not a star at all it is just a small speck of dust known as a METEOROID entering the Earth's atmosphere at very high speed.

We know of this effect j ust as the space shuttle or other space craft become very hot as they re-enter the atmosphere at about 30 ,000 km/h . However these dust particles get even hotter at their re-entry speed of up to 270 ,000 km/h. At this speed the dust is vaporised by the heat and the surrounding air is also heated until it glows in a similar way to a fluorescent light.

Increasing speed gives a travelling object a lot more energy as shown in the equation E = M x V². Writing this equation another way: Energy = Mass x Velocity x Velocity we can see that doubling the Velocity (speed) will result in the object to having four times the Kinetic Energy (Energy due to speed). For example if the speed is doubled then Energy = Mass x 2 x 2 so this is E = M x 4. It is the energy due to the very high speed of a meteoroid (the particle) that heats the atmosphere causing what we see as a streak of light crossing the sky that we call a Meteor.

There are two types of Meteor, the first is thought to originate from the large lumps of rock and iron left over when the planets formed , known as ASTEROIDS. Most asteroids orbit the Sun in a belt between Mars and Jupiter. The huge gravitational forces exerted by Jupiter may have pulled the rocks apart before they could accumulate into a planet.

Very rarely two asteroids may collide but when they do, chips of rock and Iron are thrown off and occasionally may head towards Earth. These can be a few millimetres across or up to tens or even hundreds of metres across. They are quite rare and are seen as individual ‘fireballs' . Large ones can sometimes impact the ground as METEORITES and may even cause craters.

The second type of meteor originates from a comet and is much more common. Comets are large lumps of ice, typically between five and thirty kilometres across. They orbit the Sun in an area beyond the orbits of the outer planets called the Kuiper Belt. There are millions of these objects just sitting there quietly orbiting around the Sun at enormous distances. This is the kind of meteor seen in the Leonid Shower.

THE SOLAR SYSTEM - NOVEMBER 2021

The planets at 16:30 GMT on 15th November

The chart above shows the location of the planets along the Ecliptic. The sky has been darkened to make the planets visible. The visible planets: Venus, Saturn, Jupiter, Neptune and Uranus are visible along the Elliptic from the West (right) to East (left). The planets appear low in the sky and are not well positioned for observing.

MERCURY will be very close the Sun before sunrise in the east and will not be visible this month.

VENUS will be visible in the early evening southern sky after sunset. It will be easy to find but will it require a clear view to the south western horizon. Venus has emerged from its excursion behind the Sun when it was in ‘Conjunction' with the Sun. It appeared at its Greatest Easterly Elongation on 29th October when it was at its furthest distance from the Sun.

Venus as it appeared after sunset on 29th October

MARS has now moved out of view and will not appear in the evening sky again until September 2022. It is very close to the Sun this month will be too close to the Sun and too small in diameter to be observable.

JUPITER will be rising in the east at about 01:30 and will be visible in the south west as the sky darkens. Jupiter was at opposition and its best on 20 th August. It will be at its best in the south at about 18:00 but it will be moving towards the western horizon during the evening.

SATURN will be rising in the east at about 12:30 but will be more difficult to observe than Jupiter in the turbulent air close to the horizon. Saturn will be at its best as soon as it is dark and in the south. It will be moving west and will set over the western horizon at about 21:30.

URANUS will be observable this month and will be best at 23:00 when it will be due south and at its highest point above the horizon but is small and faint at +5.7.

NEPTUNE will be just visible to the east of Jupiter (see the chart above). It is small a difficult to see at only 2.4 arc-seconds in diameter and at magnitude +7.7.

THE SUN

The Sun rises at about 07:00 at the beginning of the month and 07:35 by the end. It sets at 16:30 at the beginning of the month and 16:00 at the end of the month. It reached its highest point in the sky on 21st June which was the Summer Solstice and will be at the Autumn Equinox on the 22nd September. There have been a few Sunspots during September and October.

THE MOON PHASES DURING NOVEMBER

New Moon will be on 4th November

First Quarter will be on 11th November

Full Moon will be on 19th November

Last Quarter will be on 27th November

The line between the light side (day) on the Moon and the dark side (night) is known as the Terminator. The Terminator after New Moon and up until Full Moon is the sunrise line and the terminator after Full Moon until the next New Moon is sunset on the Moon. On the terminator the Sun casts long shadows as it does on Earth at sunset and sunrise. Shadows near the terminator give relief to the lunar terrain and produce an almost 3D perspective. So it is always best to observe an object when it is in the daylight near the Terminator.

As the Moon orbits the Earth the terminator appears to move across the surface of the Moon from night to night. The chart above shows the phases of the Moon during the month of November 2021 but to follow how the terminator moves across the Moon due to the phases we need to know where the Moon will be in the sky during the month. So let's start the following article with the New Moon and where we must look for it.

 

OBSERVING THE MOON

An image of the Full Moon

The Moon is the easiest object to observe whether it be with ‘Naked Eye', Binoculars or with a telescope. It is also quite easy to image or even photograph. One of the most interesting things to do is to follow the phases of the Moon. As the Moon moves around its orbit about Earth different areas of the Moon appear illuminated by the Sun. The Moon appears to move across the sky about 15º from west to east each night so we see the phases shown below.

The phases of the Moon as they will appear this month

The chart above shows the phases of the Moon during the month of November 2021. But to follow the phases we need to know where the Moon will be in the sky during the month. So let's start with the New Moon and where to look for it.

THE PHASES OF THE MOON

Diagram showing the Moon's orbit and its phases

The important thing about observing the Moon is to choose the best time to see the features to be studied. The reason for this is to do with the illumination of the surface of the Moon by the Sun. We know the Moon has phases caused by its movement around Earth on its monthly orbit. Each evening of the month we have a different view of the Moon and we see its shape change from a thin crescent to full Moon then a return to a thinner crescent after full Moon.

In the diagram above the Sun is shining from the right. The inner circle of Moon images demonstrate the orbit of the Moon around Earth and shows how the Moon is illuminated by the Sun. The outer Moon images show the view of the Moon as seen from Earth. From Earth the same side of the Moon is always facing us so the Moon appears not to rotate for us. However if viewed from the Sun the Moon can be seen orbiting around Earth and as it orbits it would appear to rotate once on every orbit. This means over the course of one orbit (about 29.5 days) the whole surface of the Moon will be illuminated at some time. Therefore for a given point on the Moon, a day will last for one half of the month and it will be night for the other rest of the month.

The two Moon images on the right show the Moon positioned between the Sun and Earth. From Earth the dark side of the Moon is facing towards us so we cannot see it. As the Moon moves around its orbit some of the illuminated side begins to appear and we see the Moon as a New Moon (the growing crescent shape is called ‘waxing'). After about seven days the Moon would reach the upper middle point of its orbit on the diagram and half of the illuminated side of the Moon is visible from Earth, this is called ‘First Quarter'. After a further seven days the Moon will have reached the left side of the diagram and the whole of the Moon facing Earth is illuminated this is the ‘Full Moon'.

A further seven days takes the Moon to the lower position on the diagram where the opposite side to the ‘First Quarter' is illuminated, we call this ‘Last (or Third) Quarter'. The final phase (called waning) is rarely seen by people who sleep normal hours. This is because the Moon does not rise until well after midnight in the east but will also be visible in the morning sky. The crescent becomes thinner as it draws closer to the Sun to start another New Moon.

New Moon occurs on 4th November

Although the New Moon actually occurs on 4th November it will not be visible to us until the 7th or 8th November. This is because the Moon will be very close to the Sun in the bright western sky above the horizon at sunset. The Moon passes the Sun (from our point of view) at 22:00 on 4th November but will not be far enough from the Sun for us to see it until the evenings of 7th or 8th November.

The First Quarter (Half Moon) 11th November

As the Moon moves along its orbit around Earth we see it rise over the western horizon as the New Moon. Because it has been passing in front of the Sun, the side facing the Sun is fully illuminated and the side facing towards us is dark so we can't see it. As the Moon moves away from the Sun a thin crescent of the bright illuminated side of the Moon begins to show. The Moon appears to move along the Ecliptic ( the imaginary line along which the Sun, Moon and planets appear to move across the sky) from west (our right) to east (our left). It moves about 15º further towards the east each day and after seven days it will appear as the First Quarter.

Full Moon rises in the east at 16:30 19th November BST

On about the 7th day after the actual New Moon has occurred (Conjunction with the Sun) the crescent will have widened to give us the Half Moon in the south on 11th November. The Half Moon (First Quarter) will continue to widen through its ‘Gibbous' phase until it reaches Full Moon 14 days after New Moon on 19th November.

The Last (or third) Quarter occurs on 27th November

The Last Quarter occurs about 21 days after the New Moon but it is not visible until after midnight when the Moon rises over the eastern horizon at 00:30 on 28th November. The Moon will now be starting to approach the Sun for its next ‘Conjunction' when it will pass in front of the Sun and then it will be the next New Moon.

After the Moon has passed through the Full Moon phase, on 19 th November, it will start to become visible in the early morning sky. First the nearly Full Moon will be in the west in the early morning then it will become a thinner crescent as the moves 15º across the morning sky towards the east each day.

Eventually the Moon will appear as a thin crescent low in the south east just before sunrise as it moves into Conjunction with the Sun. The next New Moon will actually occur on 4th December but will not be visible until 7th or 8th December.

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