WHAT'S UP THIS MONTH - NOVEMBER 2017
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(Link to What's Up October 2017)
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THESE PAGES ARE INTENDED TO HELP YOU FIND YOUR WAY AROUND THE SKY
Click HERE for a downloadable PDF white chart - (Close PDF file to return here)
The chart above shows the night sky as it appears on 15th November at 21:00 (9 o'clock) in the evening 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 10 o'clock GMT at the beginning of the month and at 8 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 easy to find. This month it is close to 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 this month: Uranus and Neptune throughout the night .
EXPLORING THE NIGHT SKY THIS MONTH
The Southern Night Sky during November 2017 at 21:00 GMT (9:00 pm)
The chart above shows the night sky looking south at about 21:0 GMT 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 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 constellations through which the ecliptic passes are known as the constellations of the ‘Zodiac'.
Constellations through which the ecliptic passes this month are: Capricornus (the Goat), Aquarius (the Water Carrier), Pisces (the Fishes), Aries (the Ram), Taurus (the Bull), Gemini (the Twins), Cancer (the Crab) and just off the chart to the east and soon to rise is Leo (the Lion).
The Milky Way (our Galaxy) appears to rise up from the south eastern horizon. It continues up through the constellations of Monoceros, Orion, Gemini, Auriga, Perseus and into Cassiopeia at the top of the chart. Perseus is the constellation of the month.
The outermost planet Neptune is in the constellation of Aquarius but looks small and faint and will need a telescope to see. A beginner's telescope will show Neptune as a rather fuzzy looking star with a blue tinge but a larger telescope will show it as a small blue disc. Uranus is located in the constellation of Pisces and is slightly easier to see than Neptune as is only half as far away as Neptune. It appears twice the diameter of Neptune and four times as bright so it can be seen as a small disc using a beginner's telescope with a magnification of 100x or more.
The planets Venus, Mars and Jupiter rise just before the Sun in the early morning in the east with Mercury and Saturn setting just after the Sun in the west in the evening. None of these planets are well positioned for observing.
Sitting astride the ecliptic in the south east is the constellation of Taurus (the Bull). The Taurus asterism (shape) looks like a squashed cross ‘X'. At the centre of the cross is a large, faint Open Cluster called the Hyades. It has the bright Red Giant star Aldebaran in the centre. The real beauty of Taurus is the naked eye Open Cluster M45 the Pleiades.
To the north of M45 (the Pleiades cluster in Taurus) is a line of stars defining the constellation of Perseus. The whole asterism (shape) of Perseus looks like a horse rider's stirrup. At the top of the line of stars is the beautiful object ‘the Double Cluster' best seen using binoculars.
Following Taurus along the ecliptic is Gemini (the Twins). The twin stars Pollux and Castor are easy to find. There is a lovely Messier Open Cluster M35 in Gemini just off the end of the line of stars emanating from the bright star Castor. Castor is a double star when seen in a telescope.
Close behind Taurus is the faint and elusive stars of Cancer (the Crab). Although Cancer itself is quite difficult to identify it is worth seeking out because at its centre is the lovely open cluster Messier 44 (M44) also known as Pleiades. It is faint but lovely to see using binoculars.
The last constellation worth mentioning is Leo (the Lion). Leo is one of the few constellations that do (with a little imagination) look like what they are supposed to depict. Leo resembles a sitting lion or the Sphinx in Egypt. It has a ‘hook' shape or backward ‘?' for the head and long pentagon lying on its side for the body. It will be rising over the eastern horizon at about 22:00 (10 o'clock). Leo is of interest this month because the radiant point for a meteor shower is located in the ‘?'.
The peak of the shower will be on 17th and 18th of November and as the radiant of the shower is located in Leo, it is called the Leonid shower. Every 33 years we expect a very active shower but not this year. The trails of dust left behind by the Comet 55P-Tempel-Tuttle leaves whispy trails behing as it loops around the Sun. Dust is released from the 'dirty' ice of the comet as it is warmed when it loops around the Sun. Most years the Earth passes through a gap in the main whispy structure of the trail of Meteoroids.
Meteoroids are the dust particles left behind by a comet. Meteors are the trails left by the small dust particles as the burn up in the atmosphere when Earth ploughs into them at around 100,000 km per hour. If a very large piece of rock or metal (normally a part of an asteroid) enters the atmosphere and survives to hit the ground, it is called a Meteorite.
There may a few bright fast meteors but a spectacular display is not expected this year. There may be up to 20 meteors per hour this year.
Anyone who may want to have a look for the Leonids should make themselves comfortable on a garden lounger seat with their feet pointing to the east. Look into the sky at about 45 degrees above the eastern horizon. Make sure to dress in warm clothes and a blanket cover for additional warmth.
CONSTELLATION OF THE MONTH - PERSEUS
The constellation of Perseus
The constellation of Perseus is directly overhead this month. The point in the sky directly overhead is called the Zenith and can be seen marked on the chart above in red.
The recognised asterism (shape) of the dot-to-dot figure of Perseus is ‘stirrup' or ‘tuning fork' shaped. It is surrounded by the constellations of Andromeda and Triangulum (to the west), Aries and Taurus (to the south) Auriga (to the east) with Camelopardalis and Cassiopeia (to the north). There is a rather distinct line of stars aligned between the ‘W' of Cassiopeia down to Taurus.
The bright star Algol , designated Beta Persei ( ß Persei , abbreviated to ß Per ) and is known colloquially as the Demon Star . It is a bright multiple star in the constellation of Perseus and the most famous star in the constellation. It was the first identified and best known eclipsing binary. This type of star is not an intrinsically variable star but an eclipsing binary star where one star passes in front of another. Algol is actually a three-star system, consisting of Beta Persei Aa1, Aa2, and Ab.
The large and bright primary ß Persei Aa1 is regularly eclipsed by the smaller ß Persei Aa2. Algol's combined magnitude is usually a constant +2.1 but regularly dips to +3.4 every 2.86 days (2 days, 20 hours and 49 minutes). It remains at +3.4 for about 10 hours while Aa2 is in front of Aa1. There is also a secondary eclipse (the ‘second minimum') when Aa2 is occulted (passes behind) the brighter Aa1. This secondary eclipse cannot be detected visually.
Magnitude is a measure of the brightness of a star. The lower the number the brighter the star appears. Some very bright stars may have a minus magnitude (eg. -1.2).
There are two Messier objects in Perseus these are M34 an Open Cluster and M76 a Planetary Nebula.
Messier 34 (M34)
Messier 76 (M76)
Messier 34 is a group of about 80 stars that formed together from a cloud of gas and dust called a nebula. This type of cluster is called an Open Cluster.
M76 is the remains of a star that was about the same size as our Sun but more advanced. It has used up all its Hydrogen fuel and advanced through its Red Giant phase to become a tiny White Dwarf star about the size of our Earth but still has the mass of our Sun. The outer layers of the star during the Red Giant stage were tenuous and were only loosely held by the giant star. As the star began collapse to become a White Dwarf the tenuous outer layers were lost and drifted away to become a nebula (cloud of gas). The nebula surrounding M76 has two lobes that may have been fashioned by strong magnetic fields in the dying star. This nebula will eventually disperse into the surround space and disappear. After billions of years the White Dwarf will cool and become a Black Dwarf. This is a cold, super dense, dead star that emits no light. It will be a cold dead cinder that was once a bright shining star similar to our Sun.
The most beautiful object in Perseus is the Double Cluster also known as NGC884 and NGC869. The Double Cluster can just about be seen with the naked eye but is best seen using binoculars. This is as the name implies a Double Open Custer. It is not known how this pair formed. They may have formed together in a large nebula as two clusters or may have formed in two separate nebulae and appear close together. They look best using a pair of large binoculars or using a short focus telescope (500mm or less) and a low power eyepiece.
The beautiful ‘binocular object' the Double Cluster, in Perseus.
THE SOLAR SYSTEM THIS MONTH
Chart showing the relative positions of planets on the evening of 15th November 2017
The chart above shows the relative positions of the planets this month. Uranus and Neptune are in the direction shown by the yellow arrows and can be seen from the dark of Earth and therefore appear in the night sky. The planets in the direction shown by the blue arrows are in the same direction as the Sun when viewed from Earth. We would be looking from the daytime side of Earth so or may just about see some planets just before sunrise or sunset. As these planets are in the same direction as the Sun it is difficult or impossible to see them.
Saturn and Mercury are close to the Sun and low on the south western horizon in the bright sky at sunset. Uranus and Neptune are well positioned all night in the southern sky. Venus, Mars and Jupiter can just be glimpsed in the very early morning sky just before sunrise low on the south eastern horizon in the brightening dawn sky.
MERCURY rises at 08:40 in the beginning of the month and 09:50 at the end of the month. It will rise and set after the Sun therefore will be in the daytime sky and not visible.
Mercury and Saturn setting in the south west at sunset
VENUS rises at about 06:00 this is just an hour before the Sun rises so it will be very difficult to see. See the chart below. With a very clear view to the south eastern horizon Venus may just be visible. It will appear relatively small at 10 arc-seconds and will appear nearly fully illuminated by the Sun. Venus is moving towards the Sun and will be in conjunction (pass behind) the Sun in January.
MARS rises at around 03:40 and will be in the south east as the Sun is rising and the sky begins to brighten. The Red Planet appears small at just 4.0 arc-seconds in diameter and is fading to magnitude +1.8. Mars is currently on the opposite side of the Sun to us on Earth and consequently appears very small. See the chart below.
JUPITER is just moving out from conjunction with the Sun. It rises at 06:10 at the beginning of the month and 05:25 at the end of the month. It is still close to the Sun and will not be visible. It is very low in the east as the sky is brightening before sunrise at about 07:15. It will not be in a position for observing until the New Year and that will be in the early morning before sunrise. The chart below has the sky darkened so the planets can be seen in the south east.
Jupiter, Mars and Venus rising in the east 07:00
SATURN will not be visible in the bright dusk sky close to the south western horizon as the Sun sets. The ringed planet rises at about 10:00 this month in daylight so it will not be observable. Saturn sets in the west at about 18:00 a couple of hours after the Sun. See the Mercury Chart.
URANUS will be in a very good observable position this month as it was at opposition on 19th October. This means it was due south at midnight (01:00 BST). Uranus may just be visible using a good pair of binoculars but a telescope at a magnification of 100x or higher will be needed to see it as a small blue/green disc. See the chart below.
Uranus and Neptune in the south at 20:00
NEPTUNE will be visible in the south as soon as the sky is dark. It was at opposition (due south at midnight – 01:00 BST) on 2nd September. It was then at its best position for observation this year. A telescope will be needed to show Neptune as a small blue/green disc using a magnification of 100x but it is small and difficult to find.
The Sun has been quite active over the last couple of months with some very nice sunspots even though the active phase of the Solar Cycle is drawing to a close.
The Sun rises at 07:00 at the beginning of the month and at 07:40 by the end of the month. It will be setting at 16:30 at the beginning and 15:55 by the end of the month. 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 IN NOVEMBER
The Moon phases have a monthly cycle
NEW MOON will always appear in the west at sunset
FIRST QUARTER is always in the south at sunset
FULL MOON rises in the east as the Sun is seting in the west
LAST QUARTER rises in the east after midnight
Full Moon will be on 4th November
Last Quarter will be on 10th November
New Moon will be on 18th November
First Quarter will be on 26th November
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