Explore Astronomy

Astronomy Picture of the Day
« December 2017


The Night Sky January 2018


Compiled by Ian Morison



See highlight above.

This page, updated monthly, will let you know some of the things that you can look out for in the night sky.  It lists the phases of the Moon, where you will see the naked-eye planets and describes some of the prominent constellations in the night sky during the month.


New

The author's: Astronomy Digest

which, over time, will provide useful and, I hope, interesting articles for all amateur astronomers.   A further aim is to update and add new material to link with the books recently published by Cambridge University Press and which are described on the home page of the digest.  It now includes well over 30 illustrated articles.




Image of the Month

HH666

HH666 - Carina Dust Pillar with Jet
Image HST, NASA/ESA, Domingo Pestana

This is a Hubble Telescope image of a pillar of dust, two light years in length inside of which is a young star, Herbig-Haro 666,which is emitting powerful jets.   It lies within the Carina Nebula, one of the galaxy's largets star forming regions some 7,500 light years distant in the southern skies.


Highlights of the Month


Around the 17th of January (with no Moon in the sky): find M31 - The Andromeda Galaxy - and perhaps M33 in Triangulum

M31
How to find M31
Image: Stellarium/IM

In the evening, the galaxy M31 in Andromeda is visible in the south The chart provides two ways of finding it:

1) Find the square of Pegasus.  Start at the top left star of the square - Alpha Andromedae - and move two stars to the left and up a bit.  Then turn 90 degrees to the right, move up to one reasonably bright star and continue a similar distance in the same direction.  You should easily spot M31 with binoculars and, if there is a dark sky, you can even see it with your unaided eye.   The photons that are falling on your retina left Andromeda well over two million years ago!

2) You can also find M31 by following the "arrow" made by the three rightmost bright stars of Cassiopeia down to the lower right as shown on the chart.

Around new Moon (17th Jan) - and away from towns and cities - you may also be able to spot M33, the third largest galaxy after M31 and our own galaxy in our Local Group of galaxies.   It is a face on spiral and its surface brightness is pretty low so a dark, transparent sky will be needed to spot it using binoculars (8x40 or, preferably, 10x50).   Follow the two stars back from M31 and continue in the same direction sweeping slowly as you go.   It looks like a piece of tissue paper stuck on the sky just a bit brighter than the sky background.   Good Hunting!


January 5th before dawn: A waning Moon closes on Regulus in Leo

Moon
The Moon and Regulus in the pre-dawn sky.
If clear before dawn on the 5th, a waning moon between Full Moon and Last Quarter lies just a few degrees from Regulus in Leo.


January 6th before dawn: Mars and Jupiter up close.

Jupiter
Jupiter in conjunction with Mars
If clear before dawn on the 6th and looking to the South-southeast, Mars, at magnitude 1.4, will be seen just to the right of Jupiter shining at magnitude -1.8.   At their closest they will be just 23 arc seconds apart.


January 13th before dawn: Saturn and Mercury

Saturn
Saturn, Mercury and a thin crescent Moon.
Image:Stellarium/IM

Looking Southeast before dawn on the 13th and given a very low eastern horizon, one might be able to spot Saturn at the start of its new apparition lying just above Mercury.   A very thin crescent Moon will be seen up to their right.   Binoculars may well be needed, but please do not use them after the Sun has risen.



December 26th late evening: The Moon close to the Hyades and Pleiades

Moon

In the evening if the 26th, the Moon between First Quarter and Full will lie close to the Hyades and Pleiades clusters in Taurus.








January 26th: Two Great Lunar Craters

20thJuly
Tycho and Copernicus: Ian Morison

Two great Lunar Craters: Tycho and Copernicus
This is a great night to observe two of the greatest craters on the Moon, Tycho and Copernicus, as the terminator is nearby.   Tycho is towards the bottom of Moon in a densely cratered area called the Southern Lunar Highlands.   It is a relatively young crater which is about 108 million years old.  It is interesting in that it is thought to have been formed by the impact of one of the remnents of an asteroid that gave rise to the asteroid Baptistina.   Another asteroid originating from the same breakup may well have caused the Chicxulub crater 65 million years ago.   It has a diameter of 85 km and is nearly 5 km deep.   At full Moon - seen in the image below - the rays of material that were ejected when it was formed can be see arcing across the surface.   Copernicus is about 800 million years old and lies in the eastern Oceanus Procellarum beyond the end of the Apennine Mountains.   It is 93 km wide and nearly 4 km deep and is a clasic "terraced" crater.   Both can be seen with binoculars.

Tycho's Rays
Full Moon showing Tycho's rays: Ian Morison

















A Messier Object imaged with the Faulkes Telescope: Messier 1 - The Crab Nebula

Messier 1
The Crab Nebula, M1
Image:Nik Szymanik
Faulkes Telescope North.

The Crab Nebula, M16, imaged by Nik Szymanek.
This image was taken using the Faulkes Telescope North by Nik Szymanek - one of the UK's leading astro-photograpers.   The Crab nebula - the first entry in Charles Messier's catalogue - is the remnant of a supernovae that was seen to explode in the year 1054.   It is visible as the lower right of the pair of stars at the centre of the nebula and is a "neutron star" just 30km across but weighing more than our Sun!   Under the intense pressure of gravity, the protons and electrons fused to form neutrons and the compact object became stable as gravity was opposed by "neutron degeneracy pressure" - a quantum mechanical force.   It is now spinning just under 30 times a second and emitting two opposed beams of light and radio waves which pass across our location in space.   We thus detect very regular pulses and so objects like this are called pulsars.   At 8.4 magnitudes it is easily seen in a small telescopes under dark transparent skies appearing as a smudge of light which is a little underwhelming to see!

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
January 17th January 24th January 2nd January 8th

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 is now a pre-dawn object rising some three and a half hours before the Sun at the beginning of the month with its 33 arc second disk, shining at a magnitude of -1.8, to be seen under clear skies.   As the month progresses, its apparent diameter increases to 35.8 arc seconds and it brightens to magnitude -2.   The elevation before dawn will then be sufficiently high to enable crisp views of the giant planet to be seen with the equatorial bands, sometimes the Great (but reducing in size) Red Spot and up to four of its Gallilean moons visible in a small telescope.



See highlight above.


Saturn

Saturn
The planet Saturn. Cassini - Nasa

Saturn passed behind the Sun on December 21st (superior conjunction) and reappears in the pre dawn sky this month at the start of its new apparition.   It is unlikely to be seen in the first week of January, but climbs higher and so becomes easier to spot as the month progresses and its brightness increases up to +0.6 magnitudes.   The rings were at their widest a few months ago and are still well open.



See highlight above.



Mercury

Mercury.
Messenger image of Mercury Nasa

Mercury reaches greatest elongation west on New Year's Day shining at magnitude -0.3.   It will be seen low in the Southeast before dawn and will be visible for a couple of weeks before sinking back towards the Sun.   Its angular diameter reduces from 6.7 to 4.9 arc seconds but, as the percentage illuminated surface area increases from 62% to 95%, its brightness remains constant throughout the month.




See highlight above.



Mars

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

Mars.   At the start of the month Mars lies in Libra but moves down into Scorpius at the end of the Month.   Now a morning object at the start of its new apparition, it rises four hours or so earlier than the Sun.   During the month, Mars has a magnitude increasing from 1.5 to 1.2 and an angular size of just 4.8, increasing to 5.6, arc seconds so no details will be seen on its salmon-pink surface.   Moving eastwards, Mars has a very close conjunction with Jupiter on the 7th of January.




See highlight above.




Venus

Venus
Venus showing some cloud structure

Venus, passes through superior conjunction (on the far side of the Sun) on January 9th and so cannot be observed this month.



Radar Image of Venus
Radar image showing surface features











The Stars

The Mid to Late Evening January Sky

JanuarySky
The January Sky in the south - mid to late evening.

This map shows the constellations seen in the south around midnight.   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.   Finally, up and to the left of Sirius is Procyon in Canis Minor.   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