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« January 2017


The Night Sky February 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.

February 2017: All About Refractors Part 2: Their superb image quality.

                          Imaging the Moon and planets in the Infrared
which provides additional material for both 'An Amateurs Guide...' and 'The Art of Astrophotography'.


Cambridge University Press has recently published two 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 are publishing 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 on the available equipment and additional imaging examples as in this months digest.


Image of the Month

Jupiter

Juno image of Jupiter

This image of southern Jupiter was taken by the Juno Spacecraft from a distance of 37,000 km.   The south polar region lies to the left whilst to the right is a large whitish oval which is a massive, counter clockwise, rotating storm system.   It is about half about half the diameter of Planet Earth.


Highlights of the Month



31st January to 5th February - after sunset: Venus approaches within 6 degrees of Mars

Mars
Venus comes within 6 degrees of Mars.
Image: Stellarium/IM

If clear on the evenings of the 31st of January to the 5th of February and looking southwest one could not fail to spot Venus.   But, on these nights Venus comes to within 5 degrees 23 arc minutes of Mars lying up to its left.   On the 31st of January and the 1st of February, they will be joined by a thin waxing crescent Moon.



5th February - all evening: The first quarter Moon occults stars within the Hyades Cluster.

Moon
The Moon passes through the Hyades Cluster.
Image: Stellarium/IM

If clear on the evening of the 5th and looking first to the south-southeast, one will see the first quarter Moon passing in front of the Hyades cluster in Taurus.   At around 18:42 its dark limb will occult the pair of stars Theta 1 and Theta 2 Tauri and at ~20:32, the magnitude 2.73 star 85 Tauri.   Then at 23:27 it will lie very close to magnitude -0.7 star Aldebaran - a red giant star that lies between us and the cluster.


February 11th - just before dawn: The Full Moon below Regulus in Leo

Moon/Regulus
The Full Moon below Regulus in Leo
Image: Stellarium/IM

Just before dawn and, given clear skies and a very low horizon towards the west, you should easily see the Full Moon lying below the magnitude +1.35 star, Regulus, Alpha Leonis.


February 15th - before dawn: The Moon lies close to Jupiter

Jupiter
The Moon close to Jupiter
Image: Stellarium/IM

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


February 21st: Saturn near a waning crescent Moon

Saturn
Saturn near a waning crescent Moon
Image: Stellarium/IM

Before dawn on the 21st and looking south-southeast Saturn will be seen down to the lower right of a thin waning crescent Moon.


February 26th - after sunset: Uranus close to Mars with both up to the left of Venus

Uranus, Mar and Venus
Uranus very close to Mars
Image: Stellarium/IM

This is an excellent chance to find Uranus - perhaps for the first time - shining at magnitude 5.9 just to the lower left of Mars at magnitude 1.3.   They will be just 35 arc minutes apart so Uranus will be easily spotted with Binoculars.   The turquoise disk with an angular size of just over 3 arc seconds may just be seen as such using a small telescope.


February 3rd and 17th evening: The Hyginus Rille

20thJuly
Hyginus Rille location: IM.

For some time a debate raged as to whether the craters on the Moon were caused by impacts or volcanic activity.   We now know that virtually all were caused by impact, but it is thought that the Hyginus crater that lies at the centre of the Hyginus Rille may well be volcanic in origin.   It is an 11 km wide rimless pit - in contast to impact craters which have raised rims - and its close association with the rille of the same name associates it with internal lunar events.   It can quite easily be seen to be surrounded by dark material.   It is thought that an explosive release of dust and gas created a vacant space below so that the overlying surface collapsed into it so forming the crater.

Hyginus Rille
Hyginus Crater and Rille

M109 imaged with the Faulkes Telescope

M109
Messier 109
Image: Daniel Duggan
Faulkes Telescope North.

The Galaxy M109, 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 shows the barred spiral galaxy M109 that lies at a distance of 83 million light years in the constellation of Ursa Major.   It is the brightest galaxy in the Ursa Major group of some 50 galaxies.   Our own Milky Way galaxy is now thought to be a barred spiral like M109.

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
February 26th February 4th February 11th February 18th

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 lies in Virgo some 3 and a half degrees above its brightest star, Spica.   At the start of February it rises in the east at ~00:30 but by month's end by ~22:45.   It will be due south at an elevation of 34 degrees at ~06:00 at the start and at ~04:00 by the end of February.   The size of Jupiter's disk increases slightly from 39 to 42 arc seconds as February progresses with its magnitude increasing very slightly from -2.1 to -2.3.   On February 6th, Jupiter halts its eastwards movement across the heavens and begins to move westwards in retrograde motion for several months.   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 is now a morning object, rising in the south-east at ~08:00 UT as the month begin but by about 06:30 UT at its end.     Lying in the southern part of Ophiuchus, its diameter increases from 15.6 to 16.1 arc seconds during the month as it shines at magnitude +0.5.   Towards the end of the month 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 will never gets above ~18 degrees in elevation 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, lies low in the southeast just before dawn down to the lower left of Saturn.   It brightens from -0.2 to -1.2 during the month.   It will be best seen around mid-month but no details would be expected to be seen on its disk which spans around 5 arc seconds across.





Mars

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

Mars is easy to find this month lying in Pisces up and to the left of Venus.   They are closest on February 1st with a separation of 5.4 degrees.   By month's end, as Mars continues to move eastwards and Venus begins to fall back towards the western horizon, their separation increases to just over 12 degrees.   Its brightness falls slightly from magnitude +1.1 to +1.3 whilst its angular diameter falls from 5.1 to 4.6 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 is dominating the western sky this month shining virtually at its brightest with a magnitude -4.8.   Its close proximity to a crescent Moon last month was given a lot of attention!   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 4th of February it reaches its highest elevation of 33 degrees at sunset.   Its angular size increases from 31 to 46 arc seconds during the month but at the same time the phase reduces from 40% to 18% illuminated.  These two effects compensate each other which is why the brightness stays so constant.   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. This month'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 Mid Evening February Sky

FebruarySky
The February Sky in the south-east - mid evening.

This map shows the constellations seen in the south during the 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 constellation Taurus

Taurus
Taurus

Taurus is one of the most beautiful constellations and you can almost imagine the Bull charging down to the left towards Orion. His face is delineated by the "V" shaped cluster of stars called the Hyades, his eye is the red giant star Aldebaran and the tips of his horns are shown by the stars beta and zeta Tauri. Although alpha Tauri, Aldebaran, appears to lie amongst the stars of the Hyades cluster it is, in fact, less than half their distance lying 68 light years away from us. It is around 40 times the diameter of our Sun and 100 times as bright.

The Pleiades
AAO Image of the Pleiades, M45, by David Malin

To the upper right of Taurus lies the open cluster, M45, the Pleiades. Often called the Seven Sisters, it is one of the brightest and closest open clusters. The Pleiades cluster lies at a distance of 400 light years and contains over 3000 stars. The cluster, which is about 13 light years across, is moving towards the star Betelgeuse in Orion. Surrounding the brightest stars are seen blue reflection nebulae caused by reflected light from many small carbon grains. These relfection nebulae look blue as the dust grains scatter blue light more efficiently than red. The grains form part of a molecular cloud through which the cluster is currently passing. (Or, to be more precise, did 400 years ago!)

The Crab Nebula
VLT image of the Crab Nebula

Close to the tip of the left hand horn lies the Crab Nebula, also called M1 as it is the first entry of Charles Messier's catalogue of nebulous objects. Lying 6500 light years from the Sun, it is the remains of a giant star that was seen to explode as a supernova in the year 1056. It may just be glimpsed with binoculars on a very clear dark night and a telescope will show it as a misty blur of light.

The Crab Nebula
Lord Rosse's drawing of M1

Its name "The Crab Nebula" was given to it by the Third Earl of Rosse who observed it with the 72 inch reflector at Birr Castle in County Offaly in central Ireland. As shown in the drawing above, it appeared to him rather lile a spider crab. The 72 inch was the world's largest telelescope for many years. At the heart of the Crab Nebula is a neutron star, the result of the collapse of the original star's core. Although only around 20 km in diameter it weighs more than our Sun and is spinning 30 times a second. Its rotating magnetic field generate beams of light and radio waves which sweep across the sky. As a result, a radio telescope will pick up very regular pulses of radiation and the object is thus also known a Pulsar. Its pulses are monitored each day at Jodrell Bank with a 13m radio telescope.

The constellation Orion

Orion
Orion

Orion, perhaps the most beautiful of constellations, will be seen in the south at around 11 - 12 pm during January. Orion is the hunter holding up a club and shield against the charge of Taurus, the Bull up and to his right. Alpha Orionis, or Betelgeuse, is a read supergiant star varying in size between three and four hundred times that of our Sun. The result is that its brightness varies somewhat. Beta Orionis, or Rigel, is a blue supergiant which, at around 1000 light years distance is about twice as far away as Betelgeuse. It has a 7th magnitude companion. The three stars of Orion's belt lie at a distance of around 1500 light years. Just below the lower left hand star lies a strip of nebulosity against which can be seen a pillar of dust in the shape of the chess-board knight. It is thus called the Horsehead Nebula. It shows up very well photographically but is exceedingly difficult to see visually - even with relativly large telescope.

The Orion Nebula
The Horsehead Nebula: Anglo Australian Observatory

Beneath the central star of the belt lies Orion's sword containing one of the most beautiful sights in the heavens - The Orion Nebula. It is a region of star formation and the reddish colour seen in photographs comes from Hydrogen excited by ultraviolet emitted from the very hot young stars that make up the Trapesium which is at its heart. The nebula, cradling the trapesium stars, is a beautiful sight in binoculars or, better still, a telescope. To the eye it appears greenish, not red, as the eye is much more sensitive to the green light emitted by ionized oxygen than the reddish glow from the hydrogen atoms.

The Orion Nebula
The Orion Nebula: David Malin

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