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« September 2018


The Night Sky October 2018


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.


New(ish)

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 nearly 50 illustrated articles.




Image of the Month

Cassiopeia

The Northern Milky Way with Cassiopeia and Perseus
Image: Ian Morison

The northern Milky Way is less prominent than that towards the south from as we are looking well away from the Galactic Centre.   Two intersting constellations lie along it; Cassiopeia and Perseus, with the Perseus Double Cluster lying between them.   The prominent 'V' of Cassiopeia points towards M31, the Andromeda Galaxy and, beyond, to M33 in Triangulum.   This image was taken under the pristine skies of the Kerry 'Gold Tier' dark sky reserve using a Nikon full frame camera and 24 mm prime lens on a tracking mount.   The methods by which this image was produced from the set of frames captured by the camera are detailed in an article 'Wide Field Imaging:....'that can be found on the author's Astronomy Digest whose link is above.


Three galaxies
The galaxies M31, M110 and M33

Highlights of the Month



October - still worth observing Mars.

Mars
Mars in the evening Sky

Mars came to its closest opposition to Earth since 2003 on the 27th July but, sadly its elevation has conspired to limit our views.   From the UK its maximum elevation when on the meridian is only 14 degrees when observed from a latitude of +52 degrees.   It angular size at the start of October is still 16 arc seconds so it is still worth looking for details on the surface now that the dust storm that covered much of the surface in June and July has subsided. The free program WinJUPOS will show you what should be visible on the Martian surface.

Mars
WinJUPOS Mars chart showing Syrtis Major.




October - a good month to observe Uranus with binoculars or a small telescope.

Uranus
Uranus in Aries
Image: Stellarium/IM

Uranus comes into opposition - when it is nearest the Earth - on the 23rd of October, so will be well placed both this month and next.   Its magnitude is +5.7 so Uranus, with a disk just 3.7 arc seconds across, is easily spotted in binoculars lying in the constellation Aries close to the borders of Cetus and Pisces.   It rises to an elevation of ~47 degrees when due south.   Given a small telescope it will appear as a small turquoise coloured disk.   On the night of closest approach, it will lie up to the left of a near Full Moon - whose glare might make it hard to spot!

Uranus
Uranus Finder Chart
Image: Stellarium/IM


October - still a good month to observe Neptune with a small telescope.

Neptune
Neptune in Aquarius
Image: Stellarium/IM

Neptune came into opposition - when it is nearest the Earth - on the 7th of September, so will still be well placed this month.   Its magnitude is +7.9 so Neptune, with a disk just 2.3 arc seconds across, is easily spotted in binoculars lying in the constellation Aquarius up to the left of Lambda Aquarii as shown on the charts.   It rises to an elevation of ~27 degrees when due south.   Given a telescope of 8 inches or greater aperture and a dark transparent night (around New Moon on the 9th) it should even be possible to spot its moon Triton.

Neptune
Neptune Finder Chart
Image: Stellarium/IM


October - early morning: find a Comet with binoculars.

Comet Giacobini Zinner
Comet Giacobini-Zinner
Image: Stellarium/IM

In the early hours of a clear morning one should be able to spot with binoculars the comet Giacobini-Zinner arching across the heavens as shown on the chart.   It was discovered by Michael Giacobini in December 1900, but then 're-discovered' by Ernst Zinner 6.5 years later.   Its nucleus is about 2 km across.



October - evening: find the 'Coathanger'.

The Coathanger
Brocchi's Cluster or the Coathanger
Image: Stellarium/IM

Looking upwards after dark you should spot the three stars making up the 'Summer Triangle'.   The lowest is Altair in Aquilla, up to its right is Vega in Lyra and over to its left is Deneb in Cygnus.   With binoculars sweep upwards about one third of the way from Altair towards Vega.   You should spot a nice asterism, formally 'Brocchi's Cluster' but usually called the Coathanger.   It is formed of a straight line of six stars below which is a 'hook' of four stars.   A pretty object!



October 11th - after sunset: Jupiter below a thin crescent Moon.

Jupiter
Jupiter below a very thin crescent Moon
Image: Stellarium/IM

If clear after sunset and given a very low western horizon one should be able to see Jupiter setting in the West down to the left of a very thin crescent Moon.   Binoculars might well be needed to cut through the twilight, but please do not use them until after the Sun has set.



October 14th - after sunset: Saturn to the left of a waxing crescent Moon.

Jupiter
Jupiter below a very thin crescent Moon
Image: Stellarium/IM

If clear after sunset and looking southwest, one should be able to see Saturn over to the left of a waxing crescent Moon.



October 18 - evening : Mars close to the first quarter Moon.

Mars
Mars close to the first quarter Moon.
Image: Stellarium/IM

During the evening of the 18th, Mars, in the south, will be seen close to the third quarter Moon.   A nice photo opportunity perhaps?



Learn the Mare on the Moon.

Mare on the Moon
Mare on the Moon
Image:Ian Morison

Why not use the annotated image of the full Moon to learn the locations of the Moon's Mare.  You can see some of them with your unaided eye and binoculars will enable you to spot them all.


NGC 891 imaged with the Faulkes Telescope

NGC 891
Edge-on galaxy NGC 891
Image: Danial Duggan
Faulkes Telescope North.

Galaxy NGC 891, imaged by Daniel Duggan.
This image was taken using the Faulkes Telescope North by Daniel Duggan - for some time a member of the Faulkes telescope team.   NGC 891 is an edge-on spiral lying in the constellation Andromeda at a distance of 27 million light years.   We think that this is very much as our own galaxy might look when seen edge-on.

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
October 9th October 16th October 24th October 2nd/31st

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 low in the west soon after sunset at the start of the month.   It shines at magnitude -1.8 (falling to -1.7 during the month) and has a disk some 32.6 (falling to 31.4) arc seconds across.   Jupiter's equatorial bands, sometimes the Great Red Spot and up to four of its Gallilean moons could be visible in a small telescope but its low elevation will greatly hinder our view.


See highlight above.



Saturn

Saturn
The planet Saturn. Cassini - Nasa

Saturn will be visible in the south-west at an elevation of ~14 degrees after sunset at the beginning of October.   Its disk has an angular size of 16.5 arc seconds falling to 15.7 during the month.   Its brightness reduces from +0.5 to +0.6 magnitudes as the month progresses.   The rings were at their widest last year but are still well open and spanning ~2.5 times the size of Saturn's globe.   Saturn is moving slowly eastwards in Sagittarius.   Sadly, atmospheric dispersion will greatly hinder our view and 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 magnitude -0.2 and with an angular diameter of ~6 arc seconds) might just be spotted very low in the west at the very end of the month and binoculars could well be needed - but please do not use them until after the Sun has set.   Look up and to the left of where the Sun has set as its angular separation from the Sun is not great.






Mars

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

Mars, which is now racing eastwards in Capricornus, made its closest approach to Earth since 2003 on the night of July 30th/31st.   It can be seen due south shining at a magnitude of -1.3 around 9 pm at the start of October but this falls to -0.6 by month's end when it is due south at ~8 pm.   Its angular size is 16 arc seconds at the start of October but this falls to 12 arc seconds by month's end.   With a small telescope it should 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?   A superb program WinJUPOS can be used to find what should be visible on any night.



See highlight above.




See highlight above.

Venus

Venus
Venus showing some cloud structure

Venus is not visible from the UK this month but will be seen low in the east just before sunrise by the middle of next month.

Radar Image of Venus
Radar image showing surface features











The Stars

The Evening October Sky

October Sky
The October Sky in the south - mid evening

This map shows the constellations seen towards the south in mid 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 with Perseus below.

The constellations Lyra and Cygnus

Cygnus and Lyra
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!

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.

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

The constellations Pegasus and Andromeda

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.

M 31 - The Andromeda Nebula
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
M33 in triangulum - David Malin