The Night Sky August 2010
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

:HST: NASA/ESA
This is a Hubble Space Telescope image of a pair of colliding galaxies caled the Antenna Galaxies. As the stars make up a tiny part of the volume of a galaxy there will be very few stellar collisions. But the dust and gas clouds are compressed to trigger a massive burst of star formation uualy in gian star clusters. The ultraviolet light from the very hottest stars excites the hydrogen gas to emit the hydrogen alpha line in the red part of the spectrum giving rise to what are called HII regions as they contain ionised hydrogen - that is hydrogen nuclei (protons) that have lost their electron. These are very prominent in the image.
Highlights of the Month
August 11th to 14th: View the Perseid Meteor Shower
If it is clear on the 11th to 14th of August, one will have a chance of seeing the meteors in the Perseid Meteor Shower - the year's most dependable meteor shower. It is a great year to observe the Perseids as the thin crescent Moon will have set early in the evening so its glare will not hinder our view. Look up towards the North-East from 11 pm onwards on the nights of August 11th, 12th and 13th and 14th. The peak of activity - when you might expect to see 20-30 meters an hour is predicted to be between 00:30 and 03:00 BST on the morning of the 13th. This is the best time to observe on the other nights too as Perseus is rising in the sky and the Earth is facing the meteor stream. Most meteors are seen when looking about 50 degrees away from the "radiant" (the point from which the meteors appear to radiate from) which lies between Perseus and Cassiopea. (See the star chart below) The Perseid meteors are particles, usually smaller than a grain of sand, released as the comet Swift-Tuttle passes the Sun. The shower in quite long lived, so it is worth looking out any night from the 10th to the 15th of August. Good hunting!
A Messier Object imaged with the Faulkes Telescope: M27 - a Planetary Nebula.
M27, the Dumbell Nebula, imaged by the Faulkes Telescope
This image of M27 was taken by Daniel Duggan using the Faulkes Telescope in Hawaii. It is a 2 x 2 mosaic due to its large angular size (8 x 6 arc minutes). M27 was discovered Charles Messier in 1764 and was the first planetary nebula to be discovered. It lies at a distance of 1,250 light years and is the remnant of an exploded star having an expanding shell of gas surrounding the 13.5th magnitude "White Dwarf" star at its heart. Using the 16 inch Meade Telescope at the Isle of Man Observatory under ideal conditions, the nebula was seen to have a vivid iridescent green colour - a rare case when the eye can actually observe colour in an object!
Learn more about the Faulkes Telescopes and how schools can use them: Faulkes Telescope"
August 7th - after sunset: A "Planetary Trio" of the planets Saturn,Mars and Venus.
August 7th: A close planetary grouping
Given a good low western horizon during the first week or so of August, you will see a close grouping of the planets Venus, Mars and Saturn. On the 7th, they will lies within a circle just 4.7 degrees across so qualifing for the term a "Planetary Trio" as they all lie within a circle of angular diameter 5 degrees. You will thus be able to see them in the same binocular field of view. That evening, Venus will be just 3 degrees below Saturn By the 12th August, they will have separated but be joined by a thin crescent Moon making a very nice photographic target. Venus and Mars become closer during the next ten days until on the 17th to 19th they are just 1.9 degrees apart.
August 2nd and 18th: The Straight Wall
The Straight Wall
The Straight Wall is best observed either 1 or 2 days after First Quarter (18th August: early morning best otherwise after sunset) or a day or so before Third Quarter (2nd August evening/night best). To honest, it is not really a wall but a gentle scarp - as Sir Patrick has said "Neither is it a wall nor is it straight!".
July: Find Uranus close to Jupiter
This month, Uranus lies a few degrees to the right of Jupiter. On the first of August, Uranus, at 5.8 magnitude, is close to a 6.3 magnitude star which lies between it and Jupiter some 3 degrees to its lower left. As the month progresses, Jupiter closes on Uranus and at month'e end is just 1 degree 45 arc minutes to its lower left, just below the 7th magnitude star and so forming a right angle triangle. Given a small telescope you may resolve the 3.6 arc second greenish-blue disk. With Jupiter on the left, both will be seen together in a binocular field of view and Uranus will be the brightest object in the field after Jupiter.
Observe the International Space Station

The International Space Station and Jules Verne passing behind the Lovell Telescope on April 1st 2008.
Image by Andrew Greenwood
Use the link below to find when the space station will be visible in the next few days. In general, the space station can be seen either in the hour or so before dawn or the hour or so after sunset - this is because it is dark and yet the Sun is not too far below the horizon so that it can light up the space station. As the orbit only just gets up the the latitude of the UK it will usually be seen to the south, and is only visible for a minute or so at each sighting. Note that as it is in low-earth orbit the sighting details vary quite considerably across the UK. The NASA website linked to below gives details for several cities in the UK. (Across the world too for foreign visitors to this web page.)
Note: I observed the ISS three times recently and was amazed as to how bright it has become.
Find details of sighting possibilities from your location from: Location Index
See where the space station is now: Current Position
The Moon

The Moon at 3rd Quarter. Image, by Ian Morison, taken with a 150mm Maksutov-Newtonian and Canon G7.
Just below the crator Plato seen near the top of the image is the mountain "Mons Piton". It casts a long shadow across the maria from which one can calculate its height - about 6800ft or 2250m.
new moon | first quarter | full moon | last quarter |
---|---|---|---|
Aug 10th | Aug 16th | Aug 24th | Aug 3rd |
Some Lunar Images by Ian Morison, Jodrell Bank Observatory: Lunar Images
A World Record Lunar Image
To mark International Year of Astronomy, a team of british astronomers have made the largest lunar image in history and gained a place in the Guinness Book of Records! The whole image comprises 87.4 megapixels with a Moon diameter of 9550 pixels. This allows details as small as 1km across to be discerned! The superb quality of the image is shown by the detail below of Plato and the Alpine Valley. Craterlets are seen on the floor of Plato and the rille along the centre of the Alpine valley is clearly visible. The image quality is staggering! The team of Damian Peach, Pete lawrence, Dave Tyler, Bruce Kingsley, Nick Smith, Nick Howes, Trevor Little, David Mason, Mark and Lee Irvine with technical support from Ninian Boyle captured the video sequences from which 288 individual mozaic panes were produced. These were then stitched together to form the lunar image.
Please follow the link to the Lunar World Record website and it would be really great if you could donate to Sir Patrick Moore's chosen charity to either download a full resolution image or purchase a print.
The Planets
Jupiter and, close by, Uranus.
Jupiter. At the beginning of August, Jupiter will rise in the east at ~10:30 BST and, at magnitude -2.7, will be well seen for much of the night. During the month it will gradually rise earlier and, by the end of the month, will rise about 20:30 BST and brighten to -2.9 magnitude. It will be high in the sky in the hours before dawn. This might well be worth getting up for as not only has Jupiter (presumably temporarily) lost its South Equatorial Belt but the Great Red Spot has intensified its colour so is now standing out very well! A small telescope will easily pick up Jupiters four Galilean moons as they weave their way around it. Incidently, Uranus is just three degrees (reducing to 2 degrees) west of Jupiter, shining at magnitude +5.8, so easily spotted in binoculars and both will be visible in the same field of view if Jupiter is placed towards the left of the field of view. Uranus lies just beyond a similar magnitude star. See Highlight above.
Saturn
Saturn. Now well past its best, Saturn may be seen low in the south-west after sunset lying in the western side of Virgo down to the lower left of the constellation Leo. It will be best seen about an hour after sunset shining with a magnitude of +1. The angular size of the disc stays around 16 arc seconds with the rings extending to ~37 arc seconds. The ring system, though gradually opening out, is still close to edge-on and so will appear very thin - the reason why Saturn is not a bright as it is when the rings are more open. The tilt of the rings reached a minimum of 1.7 degrees in late May and is now increasing again, reaching ~5 degrees by the end of the month. For the first time in 15 years we are now begining to see the northern face of the rings. A small telescope will easily show its brightest satellite, Titan, at magnitude 7.8, and one of 8 inches or more aperture several more.
See Highlight above.
Mercury
Mercury may still be seen very low in the west north-west just after sunset at the beginning of August, but with its brightness of +0.3 will be hard to spot just 3 degrees above the horizon in the twilight sky. Binoculars will be needed and scan about 20 degrees (~4 field widths)to the lower right of Venus. Not the best month for this planet which is usually best seen in the spring or autumn.
Mars
Mars remains visible (at magnitude +1.5) in the south-west after sunset and, moving eastwards, lies beteen the star Regulus in Leo and Spica in Virgo. Its angular size drops from 4.7 to 4.2 arc seconds during the month so any details on the surface will be impossible to spot. (Unless you have access the Hubble Space Telescope!)
See Highlight above.Venus
Venus is now very prominent in the evening sky after sunset in the west north-west. Brightening from -4.1 to -4,6, it will be easily spotted - the brightest object in the night sky after the Moon. With an angular size of 20 arc seconds as August begins and increasing to 28 arc seconds by month's end, it will appear in a telescope as a well illuminated disc like the Moon around first quarter. It reaches its greatest angular seperation (elongation) from the Sun on the 19th August. It is an interesting fact that Venus's brightness remains pretty constant at ~ -3.8 to -4.6 all the time that it is visible. As it nears the Earth, it become a thin crescent, but the fact that it is then much nearer to us means that the effective reflecting area remains virtually constant in apparent size. See Highlight above.
Find more planetary images and details about the Solar System: The Solar System
The Stars
The mid evening August Sky
Now that the evenings are drawing in the night sky gets darker earlier so encouraging one to go out to observe.
This map shows the constellations seen towards the south at about 10pm BST in mid August. High over head towards the north (not shown on the chart) lies Ursa Major. As one moves southwards one first crosses the constellation Hercules with its magnificent globular cluster, M13, and then across the large but not prominent constellation Ophiucus until, low above the souther horizon lie Sagittarius and Scorpio. To the right of Hercules lie the arc of stars making up Corona Borealis and then Bootes with its bright star Arcturus. Rising in the east is the beautiful region of the Milky Way containing both Cygnus and Lyra. Below is the constellation of Aquilla, the Eagle. The three bright stars Deneb (in Cygnus), Vega (in Lyra) and Altair (in Aquila) make up the "Summer Triangle".
The constellation Ursa Major
The stars of the Plough, shown linked by the thicker lines in the chart above, form one of the most recognised star patterns in the sky. Also called the Big Dipper, after the soup ladles used by farmer's wives in America to serve soup to the farm workers at lunchtime, it forms part of the Great Bear constellation - not quite so easy to make out! The stars Merak and Dubhe form the pointers which will lead you to the Pole Star, and hence find North. The stars Alcor and Mizar form a naked eye double which repays observation in a small telescope as Mizar is then shown to be an easily resolved double star. A fainter reddish star forms a triangle with Alcor and Mizar.
Ursa Major contains many interesting "deep sky" objects. The brightest, listed in Messier's Catalogue, are shown on the chart, but there are many fainter galaxies in the region too. In the upper right of the constellation are a pair of interacting galaxies M81 and M82 shown in the image below. M82 is undergoing a major burst of star formation and hence called a "starburst galaxy". They can be seen together using a low power eyepiece on a small telescope.
Another, and very beautiful, galaxy is M101 which looks rather like a pinwheel firework, hence its other name the Pinwheel Galaxy. It was discovered in1781 and was a late entry to Messier's calalogue of nebulous objects. It is a type Sc spiral galaxy seen face on which is at a distance of about 24 million light years. Type Sc galaxies have a relativly small nucleus and open spiral arms. With an overall diameter of 170,000 light it is one of the largest spirals known (the Milky Way has a diameter of ~ 130,000 light years).
Though just outside the constellation boundary, M51 lies close to Alkaid, the leftmost star of the Plough. Also called the Whirlpool Galaxy it is being deformed by the passage of the smaller galaxy on the left. This is now gravitationally captured by M51 and the two will eventually merge. M51 lies at a distance of about 37 million light years and was the first galaxy in which spiral arms were seen. It was discovered by Charles Messier in 1773 and the spiral structure was observed by Lord Rosse in 1845 using the 72" reflector at Birr Castle in Ireland - for many years the largest telescope in the world.
Lying close to Merak is the planetary nebula M97 which is usually called the Owl Nebula due to its resemblance to an owl's face with two large eyes. It was first called this by Lord Rosse who drew it in 1848 - as shown in the image below right. Planetary nebulae ar the remnants of stars similar in size to our Sun. When all possible nuclear fusion processes are complete, the central core collpses down into a "white dwarf" star and the the outer parts of the star are blown off to form the surrounding nebula.
The constellation Hercules
Between the constellation Bootes and the bright star Vega in Lyra lies the constellation Hercules.The Red Giant star Alpha Herculis or Ras Algethi, its arabic name, is one of the largest stars known, with a diameter of around 500 times that of our Sun. In common with most giant stars it varies its size, changing in brightness as it does so from 3rd to 4th magnitude. Lying along one side of the "keystone" lies one of the wonders of the skies, the great globular cluster, M13. Just visible to the unaided eye on a dark clear night, it is easily seen through binoculars as a small ball of cotten wool about 1/3 the diameter of the full Moon. The brightness increases towards the centre where the concentration of stars is greatest. It is a most beautiful sight in a small telescope. It contains around 300,000 stars in a region of space 100 light years across, and is the brightest globular cluster that can be seen in the northern hemisphere.
The constellation Virgo
Virgo, in the south-east after sunset this month, is not one of the most prominent constellations, containing only one bright star, Spica, but is one of the largest and is very rewarding for those with "rich field" telescopes capable of seeing the many galaxies that lie within its boundaries. Spica is, in fact, an exceedingly close double star with the two B type stars orbiting each other every 4 days. Their total luminosity is 2000 times that of our Sun. In the upper right hand quadrant of Virgo lies the centre of the Virgo Cluster of galaxies. There are 13 galaxies in the Messier catalogue in this region, all of which can be seen with a small telescope. The brightest is the giant elliptical galaxy, M87, with a jet extending from its centre where there is almost certainly a massive black hole into which dust and gas are falling. This releases great amounts of energy which powers particles to reach speeds close to the speed of light forming the jet we see. M87 is also called VIRGO A as it is a very strong radio source.
Below Porrima and to the right of Spica lies M104, an 8th magnitude spiral galaxy about 30 million light years away from us. Its spiral arms are edge on to us so in a small telescope it appears as an elliptical galaxy. It is also known as the Sombrero Galaxy as it looks like a wide brimmed hat in long exposure photographs.
The constellations Lyra and Cygnus
This month the constellations Lyra and Cygnus are rising in the East 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!
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!
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.
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.
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.
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!
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.
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.