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« June 2018


The Night Sky July 2018

For June click on link top left.


Compiled by Ian Morison




See highlight above.

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.


New

The author's: Astronomy Digest

which, over time, will provide useful and, I hope, interesting articles for all amateur astronomers.   A further aim is to update and add new material to link with the books recently published by Cambridge University Press and which are described on the home page of the digest.  It now includes over 40 illustrated articles.




Image of the Month

Gaia

Gaia all-sky map
Image: ESA,Gaia,DPAC

This wonderful all-sky view of our Milky Way galaxy and the Magellanic Clouds is not a photograph but a map based on individual measurement of well over a billion stars!   It is derived from precise determinations of position, brightness, colour and parallax distance for 1.3 billion stars - around 10% of those in the Milky Way galaxy.   the Large and Small Magellanic Clouds seen in the lower right of the image are two daughter galaxies that lie just beyond the Milky Way.   The white dot just to the left of the SMC is the globular cluster 47 Tucanae whilst the white dot just above the Milky Way making a thin triangle with the Magellanic Clouds is Omega Centauri - now thought to be the core of a galaxy whose outer stars have been stripped off by the gravitational pull of the Milky Way galaxy.


Highlights of the Month


July - still a great month to view Jupiter.

Jupiter
Jupiter imaged by Damian Peach

This is a still a great month to observe Jupiter which came into opposition on May 8th and will be visible in the southwest in the late evening   It is moving down the ecliptic and now lies in Libra so, sadly, will only reach an elevations of ~20 degrees when crossing the meridian.   An interesting observation is that the Great Red Spot appears to be diminishing in size.   At the beginning of the last century it spanned 40,000 km across but now appears to be only ~16,500 km across - less than half the size.   It used to be said that 3 Earths could fit within it, but now it is only one.   The shrinking rate appears to be accelerating and observations indicate that it is now reducing in size by ~580 miles per year.   Will it eventually disappear?

[I have imaged Jupiter recently and the Red Spot is very prominent and has a lovely orange/red colour.   These can be seen in my article 'Imaging Jupiter at Closest Approach' to be found in my Astronomy Digest ]  

The features seen in the Jovian atmosphere have been changing quite significantly over the last few years - for a while the South Equatorial Belt vanished completely (as seen in Damian's image) but has now returned to its normal wide state but is less prominent than the North Equatorial Belt.   The diagram on right shows the main Jovian features as imaged by the author at the beginning of December 2012. (When Jupiter was at a high elevation allowing a greater resolution image than now.)

The image by Damian Peach was taken with a 14 inch telescope in Barbados where the seeing can be particularly good.   This image won the "Astronomy Photographer of the Year" competition in 2011.

See more of Damian Peach's images: Damian Peaches Website"





Jovian Features
Features in Jupiter's atmosphere - December 2013.





July: Look for the Great Red Spot on Jupiter

Great Red Spot
Observe the Great Red Spot
Image: NASA

This list gives some of the best evening times during June to observe the Great Red Spot which should then lie on the central meridian of the planet. The times are in UT.

3rd   21:40        

5th   23:18        

10th   22:27        

15th 21:369        

17th 23:15        

20th 20:45        


July - observe Saturn.

Saturn
Saturn in the evening Sky

Saturn reached opposition on the 27th of June, so is now low (at an elevation of ~14 degrees) in the west-southwest as darkness falls lying above the 'teapot' of Sagittarius.   Held steady, binoculars should enable you to see Saturn's brightest moon, Titan, at magnitude 8.2.   A small telescope will show the rings with magnifications of x25 or more and one of 6-8 inches aperture with a magnification of ~x200 coupled with a night of good "seeing" (when the atmosphere is calm) will show Saturn and its beautiful ring system in its full glory.

As Saturn rotates quickly with a day of just 10 and a half hours, its equator bulges slightly and so it appears a little "squashed".   Like Jupiter, it does show belts but their colours are muted in comparison.

The thing that makes Saturn stand out is, of course, its ring system.   The two outermost rings, A and B, are separated by a gap called Cassini's Division which should be visible in a telescope of 4 or more inches aperture if seeing conditions are good.   Lying within the B ring, but far less bright and difficult to spot, is the C or Crepe Ring.

Due to the orientation of Saturn's rotation axis of 27 degrees with respect to the plane of the solar system, the orientation of the rings as seen by us changes as it orbits the Sun and twice each orbit they lie edge on to us and so can hardly be seen.   This last happened in 2009 and they are currently at an angle of 26 degrees to the line of sight.   The rings will continue to narrow until March 2025 when they will appear edge-on again.

See more of Damian Peach's images: Damian Peaches Website"




Saturn
Saturn imaged in April 2012 by Damian Peach




July - Find the globular cluster in Hercules and spot the "Double-double" in Lyra

M13
Use binoculars to find the globular cluster M13 in Hercules and the "Double-double" in Lyra
Image: Stellarium/IM

There are two very nice objects to spot with binoculars in the eastern sky well after dark this month.   Two thirds of the way up the right hand side of the 4 stars that make up the "keystone" in the constellation Hercules is M13, the best globular cluster visible in the northern sky.   The 15 minute exposure image on right was taken by the author using a 127 mm APO refractor and SBIG 8.3 megapixel CCD camera.

Just to the left of the bright star Vega in Lyra is the multiple star system Epsilon Lyrae often called the double-double.   With binoculars a binary star is seen but, when observed with a telescope, each of these two stars is revealed to be a double star - hence the name!

M13
M13 imaged by Ian Morison in May 2014



Early July: A very good time to spot Noctilucent Clouds!

May2nd
July: the chance to spot Noctilucent Clouds
Image: Wikipedia Commons

Noctilucent clouds, also known as polar mesospheric clouds, are most commonly seen in the deep twilight towards the north from our latitude.   They are the highest clouds in the atmosphere at heights of around 80 km or 50 miles.   Normally too faint to be seen, they are visible when illuminated by sunlight from below the northern horizon whilst the lower parts of the atmosphere are in shadow.   They are not fully understood and are increasing in frequency, brightness and extent; some think that this might be due to climate change!   So on a clear dark night as light is draining from the north western sky long after sunset take a look towards the north and you might just spot them!


July 9th - sunset: Venus close to Regulus in Leo

Venus
Venus and Regulus
45 minutes after sunset on the 9th, one would, if clear, see Venus shining brightly just up to the right of Regulus in Leo.   [Note: the sky brightness has been reduced in the diagram.]


July 10th before dawn: The Moon in the Hyades Cluster.

Moon
TheMoon in the Hyades Cluster
Before dawn, a thin waning crescent Moon will be seen amongst the Hyades Cluster.


July 15th, after sunset: Venus to the left of a very thin crescent Moon.

Venus
Venus near a crescent Moon..
If clear after sunset and given a very low western horizon, you should be able to spot Venus over to the left of a very thin crescent Moon.


July 19th after sunset: Jupiter below a waxing Moon.

Jupiter
Jupiter below the Moon.

After sunset on the 19th, if clear you should be abble to spot Jupiter below a waxing Moon.   Alpha Libri is to its lower left.

July 24th after sunset: Saturn close to a waxing Moon.

Saturn
Saturn and the Moon.
After sunset on the 24, Saturn will be seen, if clear, to the lower left of the waxing Moon.









July 5th and 21st: The Straight Wall

Moon
Location of the Straight Wall: IM.

The Straight Wall
The Straight Wall is best observed either 1 or 2 days after First Quarter (11th August: evening best) or a day or so before Third Quarter (evening of the 25th August 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!".

The Straight Wall
The Straight Wall at Sunrise and Sunset.

A Messier Object imaged with the Faulkes Telescope: galaxy NGC 1365.

Galaxy NGC 1365
NGC1365
Image:Nik Szymanik
Faulkes Telescope.

Galaxy NGC 1365, imaged by Nik Szymanek.
This image was taken using the Faulkes Telescope by Nik Szymanek - one of the UK's leading astro-photograpers.   NGC1365 is also known as the Great Barred Spiral Galaxy and lies at a distance of 56 million light years.   It is one of the most perfect barred spirals with a straight bar and two very prominent spiral arms.   Closer to the centre there is also a second spiral structure.   The galaxy is an excellent "laboratory" for astronomers to study how galaxies form and evolve.

Learn more about the Faulkes Telescopes and how schools can use them: Faulkes Telescope"

















Observe the International Space Station

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

3rd Quarter 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
July 13th July 19th July 27th July 6th

Some Lunar Images by Ian Morison, Jodrell Bank Observatory: Lunar Images

A World Record Lunar Image

World record Lunar Image
The 9 day old Moon.

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 9,550 pixels.  The resolution of ~0.4 arc seconds 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.

Plato and the Alpine valley
Plato and the Alpine Valley.

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 8 day old Moon

Lunar Image
The 8 day old Moon imaged by Ian Morison.

This image was taken by the author on a night in March 2018 when the Moon was at an elevation of ~52 degrees and the seeing was excellent.   This enabled the resolution of the image to be largely determined by the resolution of the 200 mm aperture telescope and the 3.75 micron pixel size of the Point Grey Chameleon 1.3 megapixel video camera.   The use of a near infrared filter allowed imaging to take place before it was dark and also reduced the effects of atmospheric turbulence.   The 'Drizzle' technique developed by the Hubble Space Telescope Institute (HSTI) was used to reduce the effective size of the camera's pixels to allow the image to be well sampled.   Around 100 gigabytes of data, acquired over a 2 hour period, was processed to produce images of 54 overlapping areas of the Moon which were then combined to give the full lunar disk in the free 'stitching' program Microsoft ICE.   A further HSTI development called 'deconvolution sharpening' was then applied to the image.   The Moon's disk is ~6,900 pixels in height and has a resolution of 0.6 to 0.7 arc seconds.   Interestingly, as seen in the inset image, the rille lying along the centre of the Alpine Valley is just discernable and this is only ~0.5 km wide!   [Due to size limitations the large image is 2/3 full size.]









The Planets

 A montage of the Solar System
A montage of the Solar System. JPL / Nasa

Jupiter

Jupiter
A Cassini image of Jupiter . Nasa

Jupiter can be seen due south soon after sunset at the start of the month and over towards the southwest as the month progresses.   It shines at magnitude -2.3 (falling to -2.1 during the month) and has a disk some 41.5 (falling to 38) arc seconds across.   Jupiter's equatorial bands and sometimes the Great Red Spot (see 'highlights' for the times when it crosses Jupiter's central meridian) and up to four of its Gallilean moons will be visible in a small telescope.   Sadly, moving slowly westwards in Libra during the month, Jupiter is heading towards the southern part of the ecliptic and will only have an elevation of ~20 degrees when crossing the meridian.   Atmospheric dispersion will thus hinder our view and it might be worth considering purchasing the ZWO Atmospheric Dispersion Corrector to counteract its effects.


See highlights above.



Saturn

Saturn
The planet Saturn. Cassini - Nasa

Saturn, was at opposition on the 27th of June and so will be visible during all the (few) hours of darkness.   It will highest in the south around midnight as July begins and a little earlier by month's end.   Its disk has an angular size of 18.4 arc seconds falling to 18.0 during the month.   Its brightness reduces from +0.0 to +0.2 magnitudes as the month progresses.   The rings were at their widest some months ago and are still, at 26 degrees to the line of sight, well open and spanning ~2.5 times the size of Saturn's globe.   Saturn, lying in Sagittarius, is close to the topmost star of the 'teapot' slowly moving in retrograde to within a few degrees of M8, the Lagoon Nebula, and M20, the Trifid Nebula.   Sadly, it will only reach an elevation of just over 15 degrees above the horizon when crossing the meridian.   Atmospheric dispersion will thus greatly hinder our view and, as for Jupiter, it might be worth considering purchasing the ZWO Atmospheric Dispersion Corrector to counteract its effects.




See highlight above.



Mercury

Mercury.
Messenger image of Mercury Nasa

Mercury shining at around zeroth magnitude early in the month reaches greatest elongation west of the Sun on July 12th.   It will be then be seen about 15 degrees down to the lower right of Venus but will have dimmed to magnitude +1 by the 17th and and then rapidly fade from view into the Sun's glare.





Mars

Mars showing Syrtis major.
A Hubble Space Telescope image of Mars.
Jim Bell et al. AURA / STScI / Nasa

Mars, in Capricornus,is moving in retrograde motion westwards as it moves towards its closest approach to Earth since 2003 on the night of July 30th/31st.   Mars begins the month rising about 2 hours after sunset shining at magnitude -2.2 but its brightness peaks at -2.8 during the final week of July.   Its angular size reachs 24.3 arc seconds at closest approach but will exceed 24 arc seconds from July 24th until August 8th.   With a small telescope it will be possible to spot details, such as Syrtis Major, on its salmon-pink surface.   From the UK, it will only reach an elevation of ~14 degrees when due south and so, sadly, the atmosphere will hinder our view.   Another reason for purchasing a ZWO Atmospheric Dispersion corrector?




See highlight above.

Venus

Venus
Venus showing some cloud structure

Venus, can be seen low in the west after nightfall sinking towards the horizon as the month progresses.   During July, its illuminated phase thins from ~70% to ~57% but, at the same time, the angular diameter of its disk increases from 16 to 20 arc seconds.   The surfac area reflecting the Sun's light thus stays roughly constant and so the brightness stays at around -4.2.   On July 9th Venus is close to Regulus in Leo and on the 15th to a waxing crescent Moon.

Radar Image of Venus
Radar image showing surface features


See highlights above.











The Stars

The late evening July Sky

July Sky
The July Sky in the south - late evening.

This map shows the constellations seen towards the south at about 10pm BST in mid July.  The most prominent star, just a little west of South, is Arcturus in Bootes.   It is the second (after Sirius) brightest star in the northern sky.  High overhead towards the north (not shown on the chart) and up to the right of Arcturus lies Ursa Major with its prominent grouping of the Plough.  As one moves southwards to the left of Bootes 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 southern horizon lie Sagittarius and Scorpius.   Those in the south of the UK - and even better in Southern Europe - will spot the bright red star Antares.   Rising in the east 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".

The constellation Ursa Major

Ursa Major
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.

M81 and M82
M81 and M82

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).

M101
M101 - The Ursa Major Pinwheel Galaxy

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.

M51
M51 - The Whirlpool Galaxy

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.

Owl Nebula Owl Nebula
M97 - The Owl Planetary Nebula Lord Rosse's 1848 drawing of the Owl Nebula

The constellation Hercules

Hercules
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.

Globular Cluster M13
The Globular Cluster M13 in Hercules. Image by Yuugi Kitahara

The constellation Virgo

Virgo
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.

M87 MERLIN images
The Giant Elliptical Galaxy M87 HST image showing the jet

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 Sombrero Galaxy
M104 - The Sombrero Galaxy

The constellations Lyra and Cygnus

Cygnus and Lyra
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!

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
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
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
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.

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.

The North American Nebula
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.

The Coathanger
Brocchi's Cluster - The Coathanger