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« February 2017


The Night Sky March 2017

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

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.

March 2017: All About Refractors Part 3: A survey and their use in astrophotography.

                      Imaging the Southern Cross region.

                      A video of making a 'Star Trails' image.

All three should be of general interest and also provide additional material for 'An Amateurs Guide to Observing and Imaging the Heavens' and 'The Art of Astrophotography'.


Cambridge University Press has recently published three books by the author. 'An Amateurs Guide to Observing and Imaging the Heavens' is a handbook aimed to bridge the gap between the beginner's books on amateur astronomy and the books which cover a single topic in great detail.   Stephen James O'Meara and Damian Peach have both given it excellent reviews.

'A Journey through the Universe' based on the lectures the author gave as Gresham Professor of Astronomy covers our current understanding of the Universe.   Martin Rees has written a very nice review of it. Last month's astronomy digest updates the chapter 'Proving Einstein Right'.

On the second of February this year CUP published a third book by the author entitled 'The Art of Astrophotography' whose aim is to cover all aspects of astrophotograpy by using a series of imaging examples (starting with just a DSLR and tripod) which detail the equipment required, the best way to undertake the imaging and, most importantly, how to process the captured data to produce high quality results.

The author's digest will be providing updates for all three books and cover new equipment and additional imaging examples.


Image of the Month

Southerncross

Centaurus, Crux and Carina constellations

These constellations, which provide what is perhaps the most beautiful and interesting region of the southern skies, were imaged by the author in February 2017. At the extreme left centre is the double star system Alpha Centauri.   A red dwarf star called Proxima Centauri and believed to orbit the central pair of stars is, at 4.2 light years distance, the nearest star to our Sun.   To its right is Beta Centauri or Hadar which is a triple star system at a distance of ~390 lightyears from Earth and around 40,000 times brighter than our Sun.

Above and to the right of Hadar close to the upper edge of the frame lies Omega Centauri: once thought to be a globular cluster, it is now thought to be the central core of a small galaxy whose outer stars have been stripped off by the gravitational effects of the Milky Way.   It may even have a black hole at its heart.   Alpha and Beta Centauri are called the pointers as they lead you towards Crux, the Southern Cross.   Further to the right is a region of nebulosity called the Eta Carina Nebula - actually larger and brighter than the Orion nebula.   Lying within it is the massive star Eta Carina which may soon become a hypernova.   Below and a little to the left is an open cluster called the 'Southern Pleiades'.   Over to the lower right is a second cross, called the 'False Cross' as it is often mistaken for the smaller Southern Cross.   Below lies an open cluster which is the 96th member of the Caldwell Catalogue - derived by Patrick Caldwell Moore.

A detailed description of how this image was taken and processed may be found in the Astronomy Digest for this month.


Highlights of the Month



1st-4th March - after sunset: Three planets and (on the 1st) a very thin crescent Moon

Mars/Venus
Venus, Mars, Uranus and a crescent Moon.
Image: Stellarium/IM

If clear on the evenings of the first few days of March and looking southwest one could not fail to spot Venus.   But, on these nights Venus is ~12 degrees down to the lower right of Mars and between them lies Uranus.  On the 1st of March they will be joined by a very thin waxing crescent Moon.



March 4th, following ~10pm : The Full Moon occults Gamma Tauri in the Hyades cluster.

Lunar Occultation
A Lunar Occultation in the Hyades Cluster.
Image: Stellarium/IM

During the late evening, the first quarter Moon will occult the star Gamma Tauri which forms the peak of the triangular shaped Hyades Cluster.   Due to parallax, the timings will vary somewhat across the UK.   After the Moon has set here, but visible across much of the USA, The Moon will occult Aldebaran.   From a thin strip from Hertford in the East to Vancouver in the West, a grazing occultation would be seen with Aldebaran disappearing and reappearing many times as its light passes though the valleys lying along the Moon's limb.


10th March - all evening: The Moon, two days before full, closes on Regulus in Leo.

Moon and Regulus
The Moon closes on Regulus.
Image: Stellarium/IM

If clear on the evening of the 10th and looking first to the east, one will see the Moon, two days before full, passing just below Regulus in Leo.


March 15th - before dawn: The Moon lies close to Jupiter and Spica.

Jupiter
The Moon close to Jupiter and Spica in Virgo.
Image: Stellarium/IM

If clear before dawn on the 15th and looking southwest, one will see Jupiter lying between the Moon to its upper left and Spica, Alpha Virginis, down to its lower left.


March 20th - before dawn: Saturn near the third quarter Moon.

Saturn
Saturn near the third quarter Moon
Image: Stellarium/IM

Before dawn on the 20th and looking South, Saturn will be seen over to the right of the third quarter Moon.


March 6th and 19th: The Alpine Valley

Alpine Valley
Alpine Valley region

An interesting valley on the Moon: The Alpine Valley
These are two good nights to observe an interesting feature on the Moon if you have a small telescope.  Close to the limb is the Appenine mountain chain that marks the edge of Mare Imbrium.   Towards the upper end you should see the cleft across them called the Alpine valley.   It is about 7 miles wide and 79 miles long.   As shown in the image is a thin rill runs along its length which is quite a challenge to observe.  The dark crater Plato will also be visible nearby.   You may also see the shadow cast by the mountain Mons Piton lying not far away in Mare Imbrium.   This is a very interesting region of the Moon!

The Alpine Valley
The Alpine valley and the crater Plato



M16, the Eagle nebula, imaged with the Faulkes Telescope

M16
Messier 16 - The Eagle Nebula
Image: Daniel Duggan
Faulkes Telescope North.

The Eagle Nebula, M16, 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.   It is a region of dust and gas where stars are now forming.   The ultraviolet light from young blue stars is stripping the electrons from hydrogen atoms so this region contains ionized hydrogen and is called an HII region.   As the electrons drop back down through the hydrogen energy levels as the atoms re-form, red light at the H alpha wavelength is emitted.   This "true colour" image is composed of red, green and blue images along with a narrow band H alpha image.   A Hubble image of the central region, called the "Pillars of Creation", has become quite famous but looks green/blue in colour.   This is a false colour image where the H alpha image has been encoded as green!

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
March 28th March 5th March 12th March 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 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.

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 Planets

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

Jupiter

Jupiter
A Cassini image of Jupiter . Nasa

Jupiter, moving towards opposition on April 7th, lies in Virgo initially some 4 degrees above its brightest star, Spica.   At the start of February it rises in the east at ~22:45 but by month's end by ~20:45.   It will be due south at an elevation of 34 degrees at ~02:00 at the start and near 00:00 (UT) by the end of March.   The size of Jupiter's disk increases slightly from 42 to 44 arc seconds as February progresses with its magnitude increasing very slightly from -2.3 to -2.5.     With a small telescope one should be easily able to see the equatorial bands in the atmosphere, sometimes the Great Red Spot and up to four of the Gallilean moons as they weave their way around it.


See highlight above.


Saturn

Saturn
The planet Saturn. Cassini - Nasa

Saturn rises well after midnight and will be highest in the pre-dawn sky.   Lying in the western part of Sagittarius, its diameter increases from 16.2 to 17 arc seconds during the month as it shines at magnitude +0.5.   It will be high enough in the south-east before dawn to make out the beautiful ring system which, at over 26 degrees to the line of sight, are as open as they ever become.   If only it were higher in the ecliptic; its elevation this year never gets above ~18 degrees and so the atmosphere will hinder our view of this most beautiful planet.   [Note: I have just acquired a ZWO Atmospheric Dispersion Corrector which uses two contra-rotating prisms to combat the dispersion of the atmosphere at low elevations.]



See highlight above.


Mercury

Mercury.
Messenger image of Mercury Nasa

Mercury passes through superior conjunction on March 7th and becomes visible around the 15th in bright twilight just above the western horizon.   On the 19th, on its way up, it passes Venus, on its way down, some 9 degrees to its right.   Then at magnitude -1.4, it brightness drops to -0.4 by the end of the month.   With an angular size increasing to 7.3 arc seconds by month's end, no details would be expected to be seen on its disk.





Mars

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

Mars is easy to find as March begins lying in Pisces up and to the left of Venus some 13 degrees down to its lower right.   As the month progresses, Mars continues to move eastwards ( moving into Aries on the 8th) whilst Venus falls back towards the western horizon.   Its brightness falls slightly during the month from magnitude +1.3 to +1.5 whilst its angular diameter falls from 4.6 to 4.1 arc seconds.   No details would be expected to be seen on its salmon-pink surface.



See highlight above.







Venus

Venus
Venus showing some cloud structure

Venus starts the month dominating the western sky shining virtually at its brightest with a magnitude -4.8.   It lies due south in mid-afternoon and can even by seen with the unaided eye.   After dark in a very dark location it can even form shadows!   On the 1st of February it has its highest elevation at sunset during the month at ~30 degrees.   But then, as the month progresses, it falls back towards the Sun as it passes in front of it (inferior conjunction) on the 25th.   Its angular size increases from 48 to 59 arc seconds during this time, but at the same time the phase reduces from 16% to 1% illuminated.   These two effects compensate each other which is why the brightness only falls to ~-4.1.   Very unusually, Venus is far enough north of the Sun that it will start rising before dawn on March 15th some 10 days before inferior conjunction.   Thus it could be seen both at nightfall and at dawn for a few days!   In visible light no details are seen on its brilliant white surface but cloud details can be seen or imaged in the ultra-violet.   In daytime when still high in the sky it can be imaged in the infrared as the blue light from the sky is filtered out.   February's astronomy digest article on imaging the Moon and planets in the infrared shows how Venus looked on the 5th of January 2017.



See highlight above.



Radar Image of Venus
Radar image showing surface features



Find more planetary images and details about the Solar System: The Solar System



The Stars

The Early Evening March Sky

March-early evening
The March Sky in the south - early evening.

This map shows the constellations seen in the south during the early evening. The brilliant constellation of Orion is seen in the south. Moving up and to the right - following the line of the three stars of Orion's belt - brings one to Taurus; the head of the bull being outlined by the V-shaped cluster called the Hyades with its eye delineated by the orange red star Aldebaran. Further up to the right lies the Pleaides Cluster. Towards the zenith from Taurus lies the constellation Auriga, whose brightest star Capella will be nearly overhead. To the upper left of Orion lie the heavenly twins, or Gemini, their heads indicated by the two bright stars Castor and Pollux. Down to the lower left of Orion lies the brightest star in the northern sky, Sirius, in the consteallation Canis Major. Up and to the left of Sirius is Procyon in Canis Minor. Rising in the East is the constellation of Leo, the Lion, with the planet Saturn up and to the right of Regulus its brightest star. Continuing in this direction towards Gemini is the faint constellation of Cancer with its open cluster Praesepe (also called the Beehive Cluster),the 44th object in Messier's catalogue. On a dark night it is a nice object to observe with binoculars. There is also information about the constellation Ursa Major,seen in the north, in the constellation details below.

The Late Evening March Sky

FebruarySky
The March Sky in the south - late evening.

This map shows the constellations seen in the south around midnight.

The constellation Gemini is now setting towards the south-west and Leo holds pride (sic) of place in the south with its bright star Regulus. Between Gemini and Leo lies Cancer. It is well worth observing with binoculars to see the Beehive Cluster at its heart. Below Gemini is the tiny constellation Canis Minor whose only bright star is Procyon. Rising in the south-east is the constellation Virgo whose brightest star is Spica. Though Virgo has few bright stars it is in the direction of of a great cluster of galaxies - the Virgo Cluster - which lies at the centre of the supercluster of which our local group of galaxies is an outlying member.

The constellation Gemini

Gemini
Gemini

Gemini - The Twins - lies up and to the left of Orion and is in the south-west during early evenings this month. It contains two bright stars Castor and Pollux of 1.9 and 1.1 magnitudes respectivly. Castor is a close double having a separation of ~ 3.6 arc seconds making it a fine test of the quality of a small telescope - providing the atmospheric seeing is good! In fact the Castor system has 6 stars - each of the two seen in the telescope is a double star, and there is a third, 9th magnitude, companion star 73 arcseconds away which is alos a double star! Pollux is a red giant star of spectral class K0. The planet Pluto was discovered close to delta Geminorum by Clyde Tombaugh in 1930. The variable star shown to the lower right of delta Geminorum is a Cepheid variable, changing its brightness from 3.6 to 4.2 magnitudes with a period of 10.15 days

Gemini
M35 and NGC 2158
This wonderful image was taken by Fritz Benedict and David Chappell using a 30" telescope at McDonal Observatory. Randy Whited combined the three colour CCD images to make the picture

M35 is an open star cluster comprising several hundred stars around a hundred of which are brighter than magnitude 13 and so will be seen under dark skies with a relativly small telescope. It is easily spotted with binoculars close to the "foot" of the upper right twin. A small telescope at low power using a wide field eyepiece will show it at its best. Those using larger telescopes - say 8 to 10 inches - will spot a smaller compact cluster NGC 2158 close by. NGC 2158 is four times more distant that M35 and ten times older, so the hotter blue stars will have reached the end of their lives leaving only the longer-lived yellow stars like our Sun to dominate its light.

Gemini
The Eskimo Nebula, NGC2392, Hubble Space Telescope

To the lower right of the constellation lies the Planetary Nebula NGC2392. As the Hubble Space Telescope image shows, it resembles a head surrounded by the fur collar of a parka hood - hence its other name The Eskimo Nebula. The white dwarf remnant is seen at the centre of the "head". The Nebula was discovered by William Herschel in 1787. It lies about 5000 light years away from us.

The constellation Leo

Leo
Leo

The constellation Leo is now in the south-eastern sky in the evening. One of the few constellations that genuinely resembles its name, it looks likes one of the Lions in Trafalger Square, with its main and head forming an arc (called the Sickle) to the upper right, with Regulus in the position of its right knee. Regulus is a blue-white star, five times bigger than the sun at a distance of 90 light years. It shines at magnitude 1.4. Algieba, which forms the base of the neck, is the second brightest star in Leo at magnitude 1.9. With a telescope it resolves into one of the most magnificent double stars in the sky - a pair of golden yellow stars! They orbit their common centre of gravity every 600 years. This lovely pair of orange giants are 170 light years away.

Leo also hosts two pairs of Messier galaxies which lie beneath its belly. The first pair lie about 9 degrees to the west of Regulus and comprise M95 (to the east) and M96. They are almost exactly at the same declination as Regulus so, using an equatorial mount, centre on Regulus, lock the declination axis and sweep towards the west 9 degrees. They are both close to 9th magnitude and may bee seen together with a telescope at low power or individually at higher powers. M65 is a type Sa spiral lying at a distance of 35 millin klight years and M66, considerably bigger than M65, is of type Sb. Type Sa spirals have large nuclei and very tightly wound spiral arms whilst as one moves through type Sb to Sc, the nucleus becomes smaller and the arms more open.

M65 and M66
The galaxies M65 and M66
M65 M66
M65 - Type Sa spiral, 9.3 magnitude M66 - Type Sb spiral, 8.9 magnitude

The second pair of galaxies, M95 and M96, lie a further 7 degrees to the west between the stars Upsilon and Iota Leonis. M95 is a barred spiral of type SBb. It lies at a distance of 38 million light years and is magnitude 9.7. M96, a type Sa galaxy, is slightly further away at 41 million light years, but a little brighter with a magnitude of 9.2. Both are members of the Leo I group of galaxies and are visible together with a telescope at low power.

M95 and M96
The galaxies M95 and M96
M95 M96
M95 - Type SBb spiral, 9.7 magnitude M96 - Type Sa spiral, 9.2 magnitude

There is a further ~9th magnitude galaxy in Leo which, surprisingly, is in neither the Messier or Caldwell catalogues. It lies a little below lambda Leonis and was discovered by William Herschel. No 2903 in the New General Catalogue, it is a beautiful type Sb galaxy which is seen at somewhat of an oblique angle. It lies at a distance of 20.5 million light years.

NGC2903
The 8.9th magnitude, type Sb, Galaxy NGC2903

The constellation Virgo

Virgo
Virgo

Virgo, rising in the east in late evening 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 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