Explore Astronomy

Astronomy Picture of the Day
« May 2022
July 2022 »


Monthly Night Sky Guide June 2022


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 over 100 illustrated articles.



Image of the Month

Earendel

The Black Hole at the centre of our Galaxy
Image: NASA, Event Horizon Telescope Consortium.

At the heart of our Milky Way Galaxy is a super-massive Black Hole weighing ~4.3 million solar masses.   Its mass was determined by the motion of stars orbiting around it.   One star reaches a speed of 12,000 km/hour as it rounds the object!   The Event Horizon Telescope has now been able to image the 'shadow' of the Black hole at very short radio wavelengths.   The main image - a composite of Chandra Xray and HST images - is 7 light years across, whilst that of the radio image is just 10 light minutes across!   This radio image follows that of the super-massive black hole at the heart of M87.   Some radio astronomers are unsure of the accuracy of the M87 image due to the sparce network of telescopes that were used to image it.   Further observations will, I hope, confirm the circular arc surrouding the shadow of the black hole.

Highlights of the Month


June 1st - before dawn: Jupiter Mars and Saturn.

Jupiter
Jupiter and Mars.
Image: Stellarium/IM

If clear before dawn and given a low eastern horizon, Jupiter and Mars will be seen close by each other.   Mars lying down to the lower left of Jupiter.   On successive days they move further apart in the pre-dawn sky.   Saturn lies well away to the upper right.

June 1st - after sunset: A thin cresent Moon and Ceres.

Moon
A thin crescent Moon and Ceres,
Image: Stellarium/IM

If clear after sunset and looking northwest, the 2.2 day old thin crescent Moon will be seen to lie down to the left of Capella in Auriga.   Up to the right of the Moon, as seen in the inset, lies the asteroid Ceres at 8.8 magnitudes.   A low horizon in this direction will be required and binoculars or a small telescope will be needed to spot Ceres - but please do not use them until after the Sun has set.

June 6th, late evening: - the Moon in Leo.

Moon
The Moon in Leo.
Image: Stellarium/IM

If clear in the late evening, a 6.7 day old Moon could be seen lying in the constellation Leo.

June 24th, before dawn : Jupiter, Mars and a thin crescent Moon

Mars
Jupiter, Mars and a thin crescent Moon..
Image: Stellarium/IM
If clear before dawn on the 24th, Mars will be seen to lie midway between Jupiter and a very thin, 25 day old, waning crescent Moon.   A low eastern horizon will be needed and, perhaps, binoculars - but please do not use them after the Sun has risen.

June 26th, before dawn : Mercury, Venus and a very thin crescent Moon

Mercury
Mercury, Venus and a thin crescent Moon.
Image: Stellarium/IM
If clear before dawn on the 26th, Mercury can be spotted down to the left of Venus and below a very thin, 27.8 day old, waning crescent Moon.   A low eastern horizon will be needed and, almost certainly, binoculars - but please do not use them after the Sun has risen.

June 8th late evening: Mons Piton and Cassini

Moon
Location of Mons Piton:IM

Mons Piton and the crater Cassini
Best seen after First Quarter, Mons Piton is an isolated lunar mountain located in the eastern part of Mare Imbrium, south-east of the crater Plato and west of the crater Cassini.   It has a diameter of 25 km and a height of 2.3 km.   Its height was determined by the length of the shadow it casts.   Cassini is a 57km crater that has been flooded with lava.   The crater floor has then been impacted many times and holds within its borders two significant craters, Cassini A, the larger and Cassini B.   North of Mons Piton can be seen a rift through the Alpine Mountains (Montes Alpes).   Around 166 km long it has a thin rille along its center.   I have never seen it but have been able to image it as canm be seen in the lunar section.

Mons Piton
Mons Piton and Cassini

A Messier Object imaged with the Faulkes Telescope: M57 in Lyra

Ring Nebula, M57
The Ring Nebula, M57
Image:Danial Duggan
Faulkes Telescope North.

Planetary Nebula M82, 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.   Lying at at distance of 2.3 thousand light years in the constellation Lyra, it is the remnant of a star like our Sun.   The core of the star has contracted down to an object about the size of the Earth supported by electron degeneracy pressure and is seen in the centre of the object.   The outer parts of the star were blasted out into space forming the "ring" (or torus) that we see.   Though showing very well in images, the central "star", called a "White Dwarf" is hard to see visually.

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


















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 third quarter
June 28th June 7th June 14th June 20th

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 is now visible in the pre-dawn sky just south of East having a magnitude of -2.25 and an angular size of 37.36 arc seconds.   By the end of the month, it it will be a little easier to spot; its magnitude having increased to -2.44 and its angular size to 40.85 arc seconds.   Sadly, its low elevation will hinder our views of the giant planet.   See highlight above.



Saturn

Saturn
The planet Saturn. Cassini - Nasa

Saturn, can be seen before dawn in the southeast.   On the first, it will have a magnitude of 0.75 and an angular size of 17.37 arc seconds with its rings spanning some 40.5 arc seconds across.   Sadly, its low elevation will hinder our view of this most beautiful planet for some time to come.   Binoculars may well be needed to spot it, but please do not use them after the Sun has risen.   By month's end, its magnitude will have increased to 0.57 with an angular size of 18.2 arc seconds.   See highlight above.




Mercury

Mercury.
Messenger image of Mercury Nasa


Mercury. If clear before dawn in the last few days of the month, Mercury, lying down to the left of Venus, could be seen shining with a magnitude of -0.46 having an angular size of 6.5 arc seconds.   Binoculars will be needed to help cut through the Sun's glare, but please do not use them after the Sun has risen.   See highlight above.





Mars

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

If clear before dawn, Mars can be seen down to the left of Jupiter in the east-southeast having a magnitude of +0.67 on the first with an angular size of 6.43 arc seconds.   As the month progresses, with the Sun rising earlier, it stays at a similar elevation before dawn with its magnitude having increased by month's end to +0.46 with an angular size of 7.22 arc seconds.   The angular size is still too small to see any details on the surface.   See highlight above.




Venus

Venus
Venus showing some cloud structure

Venus can be seen at a low elevation just north of East in the pre-dawn sky this month.   On the first it has a magnitude of -3.95 and an angular size of 13.7 arc seconds.   By month's end its brightness has fallen to -3.86 but the angular size has reduced to 11.9 arc seconds.   The brightness stays roughly the same as the reduction in angular size is compensated by the increase in its phase (illuminated percentage).   See highlight above.





The Stars

The late evening June Sky

May Sky
The June Sky in the south - late evening.

This map shows the constellations seen towards the south at about 11pm BST in mid June. 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 southern 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 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