The Night Sky November 2007
Compiled by Ian Morison
This page, updated monthly, will let you know some of the things that you can look out for in the night sky. It lists the phases of the Moon, where you will see the naked-eye planets and describes some of the prominent constellations in the night sky during the month.
Image of the Month
The open star cluster NGC3603
Image: NASA/ESA/ Hubble Heritage
NGC3603 is an open star cluster in the Carina spiral arm of our Milky Way galaxy which, sadly, cannot be seen from our northern latitudes. Some 20,000 light years distant, it is associated with one of the Milky Way's largest star formation regions and contains thousands of stars that were thought to have been formed one or two million years ago. The image is ~17 light years asross and shows clouds of interstellar gas, excited by the ultra violet light from young stars.
The Moon
The passage of the Moon through the Earth's shadow March 2007: Cape Newwise 200 mm telescope and Nikon D80 camera.
Ian Morison, Jodrell Bank Observatory
| new | first quarter | full moon | last quarter |
|---|---|---|---|
| Nov 9th | Nov 17th | Nov 24th | Nov 1st |
Some Lunar Images by Ian Morison, Jodrell Bank Observatory: Lunar Images
Highlights of the Month
November: the Comet 17P/Holmes
Comet Holmes
Image: Robin Skagell
Click on to enlarge
Comet Holmes on 31st October with 60 second exposure using an 8" SCT and Apogee AP47P camera.
Image: Copyright Lothar Kurtze.
Comet Holmes on 13th November with Meade 8" Schmidt-Newtonian and Nikon D80
Image: Ian Morison
Click on to enlarge
We have an comet in the sky - visible to the unaided eye! A comet, P17/Holmes, which is ~ 240 million km from the Earth has undergone a major outburst and is now at ~ Magnitude 3 appearing as a new star in the constellation Perseus. During November it will move westwards towards the 1.8 magnitude star Mirphak, Alpha Persei. To locate the comet in the evening sky - the chart below is for 10pm - first find the bright star Capella low in the east. Up and to the right is the slightly dimmer star Mirphak with the comet below. A chart is given below to help you locate it. Comet Holmes orbits the Sun every 6.88 years and was discovered by Edwin Holmes in November 1892. It was closest to the Sun in May this year but never gets closer than Mar's orbit. Try to observe it on the next clear night - it may not be visible for long! Any tail is likely to be very short and will be pointing away from us as the comet is nearly on the opposite side of us from the Sun.
Looking east at 10 pm
Image: Stellarium/im
Position of Comet Holmes in Perseus
Image: Stellarium/im
Nov 17th,18th and 19th - The Leonid Meteor Shower
A Leonid crossing the Sword of Orion
Every year, on November 17th and 18th, the Earth passed close to the trails of cometry debris from Comet Temple-Tuttle which produce the annual Leonid Meteor shower. The wonderful image above shows one of the 2001 Leonids burning up in the atmosphere as it crossed the constellation of Orion. This year there will be a this waning crescent Moon so it will mean that the sky will be dark so allowing faint trails to be seen. It is expected that, in general, only 12 to 15 meteors are likely to be seen per hour, but they do tend to be bright so it is worth getting up to view them. The dust particles that are swept up by the Earth are released as Comet Temple-Tuttle rounds the Sun every 33 years.
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November 5th before dawn: Venus, Saturn and the waning crescent Moon
November 5th - before dawn
Image: Stellarium/im
Perhaps the best skyscape this month will be seen, if clear, in the east before dawn on the 5th of November. Venus will be shining brightly to the left of the thin crescent Moon with Saturn up and to its right on a line between Venus and Regulus.
Seek out Uranus and Neptune with binoculars or a telescope.
This month Uranus and Neptune
Image: Stellarium/IM
November is a good month to observe the planets Uranus and Neptune - perhaps for the first time - with binocular or a small telescope. &nb &nbs On November 9th, the night of new moon, Uranus, with a magnitude of 5.8, lies just over 3 degrees up and to the left of the 4th magnitude star Lambda Aquarii. (If Lamdbda Aquarii is the centre of a clock, Uranus is at 10:00) During the month it drifts slowly westwards. Binoculars will easily show it and a small telescope will show a blue-green disc just under 4 arc seconds in angular diameter. Around the time of new moon (~9th November) under dark and transparent skies you even be able to see it with your unaided eyes. Neptune is somewhat lower in elevation in Aquarius just 5 degrees to the right of the star Delta Capricornus. It is at magnitude 7.9 so binoculars will be required to spot it. Have a go!
Find the Andromeda Galaxy and observe Algol wink!
Mid evenings through October
Image: Stellarium/IM
The autumn is a good time to find the Andromeda galaxy. It is near the top of the chart just to the right of centre. Start at the top left star (Alpheratz) of the square of Pegasus, move round two bright stars to the left and up a bit to reach Mirach. At this point turn sharp right, move up one star and then the same distance again. A fainter star is passed and then you should see a fuzzy glow - that is the Nucleus of the Andromeda Galaxy. 10x50 binoculars on a really dark transparent night will show the disk extending out from the nucleus.
To the left of the tiny constellation Triangulum is the Star Algol in Perseus.
It is an eclipsing binary and every 2.87 days its brightness drops by more than a magnitude and then rises again. In November you can watch this happen over a period of hours around 21:18 UT on the 13th and 18:06 UT on the 28th.
The Planets
During the nights around the 8th of November, it is possible to see ALL the 8 planets in the solar system in one night - Venus Saturn and Mercury before dawn, Jupiter low in the south-west at 5:30 pm, Uranus in the South-east and Neptune in the South just after 6 pm with, finally Mars rising in the east after 10 pm.
A montage of the Solar System. JPL / Nasa
Jupiter
A Cassini image of Jupiter . Nasa
Jupiter At the beginning of November, Jupiter, at magnitude of -1.9 and an angular diameter of 22 arc seconds, sets 2 hours after the Sun and so may be seen low in the south-western sky after sunset. It lies in the constellation Ophiuchus close to the most southerly point of the ecliptic - the path of the Sun and planets across the sky - so this has not been the best year in which to observe it as it has never risen high in the sky.&mnsp Sadly, it will be a few years before we see it at its best again. On the 12th on November it will lie 5 degrees above a thin crescent Moon, just 3 days after new moon and on the 13th November it will lie 11 degrees to right of the crescent Moon. To be totally honest, its probably not worth observing until it appears in the pre-dawn sky in a few months time.
A small telescope (or even binoculars resting on a wall to steady them) will allow you to observe the 4 bright Galilean Moons, Io, Europa, Ganymede and Callisto, discovered by Galilo Galilei in 1610.
Saturn
The planet Saturn. Cassini - Nasa
Saturn As November begins, Saturn lies 6.5 degrees down to the lower left of the star Regulus in Leo and is seen in the pre-dawn sky. It stars the month at magnitude +0.8 with an angular size of 17.3 arc seconds. Saturn will not be as bright this coming year as it sometimes is: the rings are closing (just ~ 8 degrees tilt to us and subtending only 5 arc seconds) and thus there is less apparent reflecting area. the rings will be seen (or rather - not seen) edge on in 2009 and it will not be until 2016 that they will be at their widest again. A small telescope will easily show its moon, Titan, and show some bands around the surface. As Saturn gradually rises earlier than the Sun and can be seen higher in the sky, it will be easier to make out its surface features. See also the highlight above.
Mercury
Mariner 10 composite image of Mercury. Nasa
Mercury On the 8th of November, Mercury reaches what is called western elongation - when it is furthest in angle from the Sun and can be glimpsed in the pre-dawn sky. On this day Mercury will be ~ 30 degrees above the eastern horizon down to the left of the star Denebola - the tail of Leo - at about 5 am. It is worth trying to observe it for a week on either side of the 8th. Binoculars will be a great help in searching for Mercury which will be quite bright at magnitude -0.4.
Note that the blank region in the image above is simply because this part of Mercury's surface has not yet been imaged in detail.
Mars
A Hubble Space Telescope image of Mars.
Jim Bell et al. AURA / STScI / Nasa
Mars, seen in the constellation Gemini this month, reaches magnitude -0.7 by the 5th of November and increases as the month progresses reaching -1.2 by the 25th. The seperation between the Earth and Mars is now decreasing as it heads towards opposition - when the Earth lies between Mars and the Sun and is closest to us. Its angular size is thus increasing and will reach 15 arc seconds by months end. At the beginning of November its angular size is already 12 arc seconds and details, such as its polar caps and dark regions of its surface such as Syrtis Major should be visible using a small telescope. Up to the 15th November, Mars will be seen to move eastwards through the constellation Gemini but then, as the Earth passes Mars "on the inside track", Mars begins to retrace its steps and moves westwards through the constellation. This is known as retrogarde motion and will take Mars back into Taurus before, on the 2nd of February 2008, it moves eastwards again reaching Gemini on the 6th March. These next few months are thus the best time to observe Mars which will be closest to Earth on the 19th of December.
Venus
Venus showing some cloud structure
Venus dominates the morning sky shining with a magnitude of -4.4 during the month. It lies in the constellation Virgo. On the first of November it is a fraction more than half phase with an angular size of 22.3 arc seconds. As the month progresses, the angular size drops to below 18 arc seconds, but the illuminated area of the surface increases. These two factors which affect its brightness roughly cancel out and the brightness hardly drops - ending the month at -4.3 magnitudes. As it is never that high above the horizon, dispersion in the atmosphere tends to colour its image and it will be seen best in a telescope when a filter is used to observe it at one colour of light such as by the use of a green filter. A narrow band filter, such as an O III filter, will give even cleaner images.
Radar image showing surface features
Find more planetary images and details about the Solar System: The Solar System
The Stars
The Evening November Sky
The November Sky in the south - early evening
This map shows the constellations seen towards the south in early evening. To the south in early evening moving over to the west as the night progresses is the beautiful region of the Milky Way containing both Cygnus and Lyra. Below is Aquilla. The three bright stars Deneb (in Cygnus), Vega (in Lyra) and Altair (in Aquila) make up the "Summer Triangle". East of Cygnus is the great square of Pegasus - adjacent to Andromeda in which lies M31, the Andromeda Nebula. To the north lies "w" shaped Cassiopeia and Perseus. The constellation Taurus, with its two lovely clusters, the Hyades and Pleiades is rising in the east during the late evening.
The constellations Lyra and Cygnus
Lyra and Cygnus
This month the constellations Lyra and Cygnus are seen almost overhead as darkness falls with their bright stars Vega, in Lyra, and Deneb, in Cygnus, making up the "summer triangle" of bright stars with Altair in the constellation Aquila below. (see sky chart above)
Lyra
Lyra is dominated by its brightest star Vega, the fifth brightest star in the sky. It is a blue-white star having a magnitude of 0.03, and lies 26 light years away. It weighs three times more than the Sun and is about 50 times brighter. It is thus burning up its nuclear fuel at a greater rate than the Sun and so will shine for a correspondingly shorter time. Vega is much younger than the Sun, perhaps only a few hundred million years old, and is surrounded by a cold,dark disc of dust in which an embryonic solar system is being formed!
There is a lovely double star called Epsilon Lyrae up and to the left of Vega. A pair of binoculars will show them up easily - you might even see them both with your unaided eye. In fact a telescope, provided the atmosphere is calm, shows that each of the two stars that you can see is a double star as well so it is called the double double!
Epsilon Lyra - The Double Double
Between Beta and Gamma Lyra lies a beautiful object called the Ring Nebula. It is the 57th object in the Messier Catalogue and so is also called M57. Such objects are called planetary nebulae as in a telescope they show a disc, rather like a planet. But in fact they are the remnants of stars, similar to our Sun, that have come to the end of their life and have blown off a shell of dust and gas around them. The Ring Nebula looks like a greenish smoke ring in a small telescope, but is not as impressive as it is shown in photographs in which you can also see the faint central "white dwarf" star which is the core of the original star which has collapsed down to about the size of the Earth. Still very hot this shines with a blue-white colour, but is cooling down and will eventually become dark and invisible - a "black dwarf"! Do click on the image below to see the large version - its wonderful!
M57 - the Ring Nebula
Image: Hubble Space telescope
M56 is an 8th magnitude Globular Cluster visible in binoculars roughly half way between Alberio (the head of the Swan) and Gamma Lyrae. It is 33,000 light years away and has a diameter of about 60 light years. It was first seen by Charles Messier in 1779 and became the 56th entry into his catalogue.
M56 - Globular Cluster
Cygnus
Cygnus, the Swan, is sometimes called the "Northern Cross" as it has a distinctive cross shape, but we normally think of it as a flying Swan. Deneb,the arabic word for "tail", is a 1.3 magnitude star which marks the tail of the swan. It is nearly 2000 light years away and appears so bright only because it gives out around 80,000 times as much light as our Sun. In fact if Deneb where as close as the brightest star in the northern sky, Sirius, it would appear as brilliant as the half moon and the sky would never be really dark when it was above the horizon!
The star, Albireo, which marks the head of the Swan is much fainter, but a beautiful sight in a small telescope. This shows that Albireo is made of two stars, amber and blue-green, which provide a wonderful colour contrast. With magnitudes 3.1 and 5.1 they are regarded as the most beautiful double star that can be seen in the sky.
Alberio: Diagram showing the colours and relative brightnesses
Cygnus lies along the line of the Milky Way, the disk of our own Galaxy, and provides a wealth of stars and clusters to observe. Just to the left of the line joining Deneb and Sadr, the star at the centre of the outstretched wings, you may, under very clear dark skys, see a region which is darker than the surroundings. This is called the Cygnus Rift and is caused by the obscuration of light from distant stars by a lane of dust in our local spiral arm. the dust comes from elements such as carbon which have been built up in stars and ejected into space in explosions that give rise to objects such as the planetary nebula M57 described above.
There is a beautiful region of nebulosity up and to the left of Deneb which is visible with binoculars in a very dark and clear sky. Photographs show an outline that looks like North America - hence its name the North America Nebula. Just to its right is a less bright region that looks like a Pelican, with a long beak and dark eye, so not surprisingly this is called the Pelican Nebula. The photograph below shows them well.
The North American Nebula
Brocchi's Cluster An easy object to spot with binoculars in Gygnus is "Brocchi's Cluster", often called "The Coathanger",although it appears upside down in the sky! Follow down the neck of the swan to the star Alberio, then sweep down and to its lower left. You should easily spot it against the dark dust lane behind.
Brocchi's Cluster - The Coathanger
The constellations Pegasus and Andromeda
Pegasus and Andromeda
Pegasus
The Square of Pegasus is in the south during the evening and forms the body of the winged horse. The square is marked by 4 stars of 2nd and 3rd magnitude, with the top left hand one actually forming part of the constellation Andromeda. The sides of the square are almost 15 degrees across, about the width of a clentched fist, but it contains few stars visibe to the naked eye. If you can see 5 then you know that the sky is both dark and transparent! Three stars drop down to the right of the bottom right hand corner of the square marked by Alpha Pegasi, Markab. A brighter star Epsilon Pegasi is then a little up to the right, at 2nd magnitude the brightest star in this part of the sky. A little further up and to the right is the Globular Cluster M15. It is just too faint to be seen with the naked eye, but binoculars show it clearly as a fuzzy patch of light just to the right of a 6th magnitude star.
Andromeda
The stars of Andromeda arc up and to the left of the top left star of the square, Sirra or Alpha Andromedae. The most dramatic object in this constellation is M31, the Andromeda Nebula. It is a great spiral galaxy, similar to, but somewhat larger than, our galaxy and lies about 2.5 million light years from us. It can be seen with the naked eye as a faint elliptical glow as long as the sky is reasonably clear and dark. Move up and to the left two stars from Sirra, these are Pi amd Mu Andromedae. Then move your view through a rightangle to the right of Mu by about one field of view of a pair of binoculars and you should be able to see it easily. M31 contains about twice as many stars as our own galaxy, the Milky Way, and together they are the two largest members of our own Local Group of about 3 dozen galaxies.
M31 - The Andromeda Nebula
M33 in Triangulum
If, using something like 8 by 40 binoculars, you have seen M31 as described above, it might well be worth searching for M33 in Triangulum. Triangulum is
the small faint constellation just below Andromeda. Start on M31, drop down to Mu Andromedae and keep on going in the same direction by the same distance as you have moved from M31 to Mu Andromedae. Under excellent seeing conditions (ie., very dark and clear skies) you should be able to see what looks like a little piece of tissue paper stuck on the sky or a faint cloud. It appears to have uniform brightness and shows no structure. The shape is irregular in outline - by no means oval in shape and covers an area about twice the size of the Moon. It is said that it is just visible to the unaided eye, so it the most distant object in the Universe that the eye can see. The distance is now thought to be 3.0 Million light years - just greater than that of M31.
M33 in triangulum - David Malin
The constellation Taurus
Taurus
Taurus is one of the most beautiful constellations and you can almost imagine the Bull charging down to the left towards Orion. His face is delineated by the "V" shaped cluster of stars called the Hyades, his eye is the red giant star Aldebaran and the tips of his horns are shown by the stars beta and zeta Tauri. Although alpha Tauri, Aldebaran, appears to lie amongst the stars of the Hyades cluster it is, in fact, less than half their distance lying 68 light years away from us. It is around 40 times the diameter of our Sun and 100 times as bright.
The Hyiades and Pleiades. Copyright: Alson Wong.
More beautiful images by Alson Wong : Astrophotography by Alson Wong
To the upper right of Taurus lies the open cluster, M45, the Pleiades. Often called the Seven Sisters, it is one of the brightest and closest open clusters. The Pleiades cluster lies at a distance of 400 light years and contains over 3000 stars. The cluster, which is about 13 light years across, is moving towards the star Betelgeuse in Orion. Surrounding the brightest stars are seen blue reflection nebulae caused by reflected light from many small carbon grains. These relfection nebulae look blue as the dust grains scatter blue light more efficiently than red. The grains form part of a molecular cloud through which the cluster is currently passing. (Or, to be more precise, did 400 years ago!)
VLT image of the Crab Nebula
Close to the tip of the left hand horn lies the Crab Nebula, also called M1 as it is the first entry of Charles Messier's catalogue of nebulous objects. Lying 6500 light years from the Sun, it is the remains of a giant star that was seen to explode as a supernova in the year 1056. It may just be glimpsed with binoculars on a very clear dark night and a telescope will show it as a misty blur of light.
Lord Rosse's drawing of M1
Its name "The Crab Nebula" was given to it by the Third Earl of Rosse who observed it with the 72 inch reflector at Birr Castle in County Offaly in central Ireland. As shown in the drawing above, it appeared to him rather lile a spider crab. The 72 inch was the world's largest telelescope for many years. At the heart of the Crab Nebula is a neutron star, the result of the collapse of the original star's core. Although only around 20 km in diameter it weighs more than our Sun and is spinning 30 times a second. Its rotating magnetic field generate beams of light and radio waves which sweep across the sky. As a result, a radio telescope will pick up very regular pulses of radiation and the object is thus also known a Pulsar. Its pulses are monitored each day at Jodrell Bank with a 13m radio telescope.
