Mercury reached inferior conjunction on January 30th and consequently was too close to the Sun to be observable. However, since the planet moves fast it takes less than two weeks before it reappears as a morning object for observers at tropical and Southern Hemisphere latitudes. Mercury then climbs higher in the sky each subsequent morning until peaking on February 24th, when it reaches greatest elongation west (26.7 degrees from the Sun). From northern temperate latitudes, the angle of the ecliptic is not favourable and during this time the planet is unsuitably placed for observation.
As often is the case with Mercury apparitions, one hemisphere of the Earth is favoured over the other. On this occasion it's the Southern Hemisphere with the added bonus that this also happens to be the most favourable morning apparition of the year. With an extended period of visibility the opportunity to spot the illusive planet over the next few weeks is superb.
For example, from latitude 35S (approx. equal to Sydney, Cape Town and Santiago) Mercury (mag. +0.3) will appear 13 degrees above the eastern horizon 45 minutes before sunrise on February 14th. The planets altitude continues to improve slightly each subsequent morning until February 24th when it peaks at 16 degrees above the horizon. Mercury shines at mag. 0.0 on this day.
The diagram below shows the February and March apparition of Mercury from latitude 35S. The thin waning crescent Moon passes 3.5 degrees north of Mercury on February 17th.
From northern temperate latitudes, Venus is a brilliant evening object visible above the west-southwestern horizon after sunset. At the start of the month the planet sets over 2 hours after the Sun from such latitudes increasing to over 3 hours by months end. Even though it's currently languishing towards the lower end of its brightness scale (mag. -3.9) Venus is always brighter than any other planet.
During September the phase of Venus decreases from 92% to 87% with the apparent diameter increasing marginally from 11 to 12 arc seconds. From the Southern Hemisphere, Venus appears low down above the western horizon and sets just over 1 hour after the Sun.
On February 21st, Venus passes less than 0.5 degrees south of Mars. At magnitude +1.3 the "Red planet" is over one hundred times fainter than brilliant Venus! The waxing crescent Moon is nearby on the same day making a lovely grouping in the early evening sky.
Mars remains an early evening object towards the west during February. The fourth planet from the Sun continues its rapid direct eastward motion against the background stars. It starts the month in Aquarius before crossing into Pisces on February 11th where it remains for the rest of the month. At magnitude +1.2, Mars is not that bright and there are currently 17 night-time stars brighter! Mars will be very close to Venus on the evening of February 21st with the Moon also nearby.
By months end, Mars sets 2.5 hours after the Sun from northern temperate latitudes but only 1 hour for those located further south.
Jupiter reaches opposition on February 6th and therefore visible all night. On this day, the giant planet rises in the east when the Sun sets in the west and then sets in the west as the Sun rises again for the new day. At magnitude -2.6, Jupiter is far brighter than any night-time star and unmistakable due to its brilliance.
This year at opposition, Jupiter is located 4.346 AU (650.18 million kilometers or 404.01 million miles) from Earth, which gives it an apparent size of 45 arc seconds. The planet is currently moving retrograde and spends the first few days of the month in Leo before crossing the constellation boundary into Cancer on February 4th. Jupiter's current declination of +16 degrees favours Northern Hemisphere based observers with the planet appearing higher in the night sky and visible for a longer period of time.
To the naked eye Jupiter appears creamy or off-white in colour. Unlike the brightest stars it doesn't twinkle at all. Compare the planet (or any other bright planet) with Sirius (α CMa - mag. -1.45) the brightest star in the night sky. Sirius twinkles and flashes many different colours particularly when close to the horizon but Jupiter doesn't twinkle at all.
A pair of 7x50 or 10x50 binoculars will reveal the planets disk although it's small. Also visible are Io, Europa, Ganymede and Callisto, the four large Galilean moons. As they orbit Jupiter they constantly change position; sometimes all four are visible but often some or all of the satellites will be temporarily obstructed and hidden as they pass behind or in front of Jupiter's disk.
When viewed through a telescope, Jupiter is an awesome sight. A 80mm (3.1 inch) scope shows the main northern and southern equatorial cloud belts and finer details along with the Galilean moons. Larger telescopes reveal much more detail including smaller belts, ovals, festoons, darkenings and of course the famous "Red Spot".
On February 4th, the full Moon passes 5 degrees south of Jupiter.
Saturn is now a morning object moving direct in northern section of Scorpius "the Scorpion". The planet is located a few degrees northwest of Antares (α Sco mag. +1.0) the brightest star in the constellation. Saturn is currently far better seen from the southern latitudes where by months end it rises well before midnight. From northern temperate locations Saturn rises around 1:30am at the end of February.
Saturn brightens from mag. +0.6 to +0.5 as the month progresses with its apparent size increasing marginally from 16 to 17 arc seconds. On February 13th, the last quarter Moon passes 2 degrees north of the planet.
Uranus, mag. +5.9, remains an early evening object during February. The distant ice giant is visible towards the west as soon as it's dark enough. The planet is easily visible with binoculars but by months end sets less than 3 hours after the Sun.
Uranus is currently located in Pisces close to the Cetus border and about 20 degrees southeast of the Great Square of Pegasus. At the end of the February, Venus (mag. - 3.9) and Mars (mag. +1.3) are less than 10 degrees southwest of the much fainter Uranus.
On February 21st, the waxing crescent Moon passes 0.3 degrees north of Uranus and an occultation is visible from southeast Canada and northeast America at 22:16 UT.
Neptune reaches solar conjunction on February 26th and therefore is not visible this month.
The brightest comet that can be seen in the night sky at the moment is comet Lovejoy (C/2014 Q2). At the end of December it was a superb binocular/telescope sight, faintly visible to naked eye as it moved through the southern constellations of Columba and Lepus. The comet then continued to brighten until peaking at magnitude +3.9 during closest approach to the Earth on January 7th. On this day it was 0.469 AU (70.2 million km or 43.6 million miles) distant from our planet and although the bright Moon somewhat interfered, the comet was easily visible with binoculars and small scopes as a large hazy circular patch of light. When imaged or photographed it displayed a long thin wispy green tail that extended over 10 degrees in length.
Now fading Lovejoy remains excellently placed for observation from the Northern Hemisphere during February. As the month progresses it's expected to fade from magnitude +4.8 to +6.3. For the first part of February the comet should still be visible to the naked eye and will remain an easy binocular and small telescope target for quite sometime to come.
From southern latitudes the comet maybe glimpsed low down above the northern horizon at the start of February. However, for these observers it isn't long before it disappears from view completely. On January 30, Lovejoy reaches perihelion (closest point to the Sun) at 1.2908 AU equivalent to 193.1 million kilometres or 120 million miles.
Location and star chart
During February, Lovejoy continues its northwesterly motion against the background stars. The comet starts the month in southeastern Andromeda close to the border with Triangulum and Perseus. On February 1st it's located 4 degrees southeast of star Almach (γ And - mag. +2.1) and is expected to shine at magnitude +4.8. Over the next few nights the comet moves closer to Almach and on February 5th the two objects are separated by only 0.5 degrees.
Although Lovejoy is now moving away from the Earth and heading into deep space it still moves reasonably quickly against the night sky backdrop. It's possible to notice its motion from one night to the next and even in a single observing session. On February 20th/21st the comet passes less than half a degree west of M76, the Little Dumbbell nebula in Perseus. At magnitude +10.1 and spanning 2.7 x 1.8 arc minutes this planetary nebula is one of the faintest, smallest and difficult objects in Messier's catalogue.
February offers an excellent opportunity for northern-based observers to follow comet Lovejoy. It based high in the sky and should be visible through binoculars or small scopes as a fading fuzzy nebulous patch of light that may even appear slightly greenish with a small tail.
The finder charts below show the positions of the comet from January 18th to March 1, 2015.
Jupiter the Solar System's largest planet has been well placed for observation for a few months now as it moves retrograde amongst the stars of Leo. Since the end of last year the planet was visible in early evening, appearing as a spectacular dazzling object. On February 6th, Jupiter is at its best for 2015 when the giant planet reaches opposition. On this day, it will rise in the east as the Sun sets and then set in west as the Sun re-rises on the opposite side of the sky. With a magnitude of -2.6, the "King of the planets" is unmistakable and far brighter than any nighttime star.
Jupiter stars the month in western Leo before crossing the constellation boundary into Cancer on February 4th where it remains for the rest of the month. Positioned 12 degrees southeast of Jupiter is Regulus (α Leo - mag. +1.4) the brightest star in Leo with the Gemini twin stars of Castor (α Gem - mag. +1.6) and Pollux (β Gem - mag. +1.2) located 25 degrees northwest of Jupiter. Although all three stars are bright, Jupiter far outshines them being about 35x brighter than Pollux and 40x brighter than Castor and Regulus.
The current northern declination of Jupiter slightly favours Northern Hemisphere observers, but even from southern latitudes where the planet appears lower down it's still unmistakable due to its brightness.
At opposition, Jupiter is located 4.346 AU (650.18 million kilometers or 404.01 million miles) from Earth. Although Jupiter is slightly further from Earth than during the last few oppositions its apparent size is still an impressive 45.4 arc seconds. Of all other planets only Venus - on rare occasions - displays a greater apparent size than Jupiter. At very favourable oppositions, when Jupiter is closest to Earth, it can reach magnitude -2.9 with an apparent size of over 50 arc seconds.
Popular 7x50 and 10x50 binoculars will reveal the disk of Jupiter. It appears off white or creamy coloured but no surface details are visible. Also visible are the four large Galilean moons (Io, Europa, Ganymede and Callisto). The moons continuously change position as they orbit Jupiter and sometimes all four are visible, but on other occasions some or all of the satellites will be temporarily obstructed and hidden as they pass behind or in front of Jupiter's disk.
NGC 4236 is a tenth magnitude barred spiral galaxy in Draco that's visible through small telescopes, although best seen with larger instruments. The galaxy was discovered by German born British astronomer William Herschel on April 6, 1793 and is a member of the Ursa Major or M81 group of galaxies that contains at least 34 galaxies, including spectacular M81 (Bode's galaxy) and M82 (Cigar galaxy).
NGC 4236 is located in the far northern constellation of Draco about 15 degrees north of the seven stars that form the famous "Plough" or "Big Dipper" asterism of Ursa Major. The galaxy is positioned two-thirds of the way along an imaginary line connecting stars lambda Dra (λ Dra - mag. +3.8) and kappa Dra (κ Dra - mag. +3.9). Star HD 106574 (mag +5.7) is 0.75 degrees directly north of NGC 4236.
Due to its high northerly declination, NGC 4236 is a Northern Hemisphere object. The best months to look for it are March, April or May although from most northern locations it's visible all year round and never sets. It can be seen from the Southern Hemisphere but only from latitudes north of 20 degrees south and even then appears low down above the northern horizon at best.
The New Year is off to a fine start for astronomers with comet Lovejoy (C/2014 Q2) now bright enough to be seen with the naked eye. When it was discovered on August 17, 2014 the comet was predicted to reach about magnitude +8 and hence within binocular range but too faint to be seen with the naked eye. However, Lovejoy has exceeded expectations and is now bright enough to seen without optical aid from a reasonably dark site.
On January 7th, Lovejoy reached closest approach to Earth at 0.469 AU (70.2 million km or 43.6 million miles). On this day it shone at magnitude +4.5 in the constellation of Eridanus just west of magnificent Orion. Since it was two days after full Moon, spotting the comet with the naked eye was difficult but easy with binoculars, appearing as obviously non-stellar hazy patch of light. Photographically, Lovejoy appeared green in colour with a long thin tail. Prospects for the remainder of the month are even better, the Moon has now past full and although the comet is now receding from Earth, it should remain within naked eye visibility for a few weeks to come.
Location and star chart
Comet Lovejoy started January in the constellation of Lepus moving on a northwesterly trajectory. On January 2nd, it moved into the large winding constellation of Eridanus remaining there for a week before crossing into Taurus on January 9th. Continuing northwards, Lovejoy crosses into Aries on January 16th and then Triangulum on January 24th. At the very end of the month it moves into Andromeda.
From northern locations the comet is superbly placed throughout January. It's visible almost all night and at its highest appears above the southern horizon at about 11pm. Those located at southern latitudes can follow the comet for most of the month although towards the end January it will appear low down above the northern horizon. It's expected to have faded to magnitude +5.3 on January 31st.
Over the next few weeks Lovejoy should be a fantastic sight for all those who are able to see it. The finder charts below show the positions of the comet from January 6th to January 30th, 2015.
NGC 2362 is a small compact young open cluster in Canis Major that surrounds bright star Tau Canis Majoris (τ CMa - mag. +4.37). This attractive grouping of 60 stars is packed into an area spanning just 6 arc minutes of apparent sky. The apparent magnitude of the cluster is given as +4.1, however the value is misleading as its skewed significantly because of the brilliance of τ CMa. The remaining members of NGC 2362 are much fainter, the brightest being of 7th magnitude.
Finding NGC 2362 is not difficult. It's located 2.75 degrees northeast of Wezen (δ CMa - mag. +1.83) the third brightest star in Canis Major. Sirius (α CMa) the brightest star in the night sky (mag. -1.46) is positioned 11 degrees to the northwest. Tau CMa a spectroscopic multiple system that shines with a combined light of tens of thousands times that of the Sun is the stand out cluster member and bright enough to be seen with the naked eye. For comparison, the Sun at the same distance would shine at a feeble magnitude +15.
NGC 2362 was discovered by Giovanni Batista Hodierna sometime before 1654 and then re-discovered by William Herschel on March 4, 1783. It's best seen from southern latitudes during the months of December, January and February.
NGC 2261 is a curious variable reflection nebula in Monoceros that's known as Hubble's Variable Nebula. It was discovered by William Herschel in 1783 and is illuminated by variable star R Monocerotis (R Mon). The nebula is unusual in that it changes shape over just a period of days and can vary by up to 2 magnitudes in brightness. The variations are believed to be due to periodic changes in the amount of dust surrounding R Mon, thus affecting the amount of light that reaches us. With an apparent magnitude of +9.0, it can be spotted with binoculars under dark skies.
The variability of R Mon (between magnitudes +10 and +12) was discovered at the Athens Observatory in 1861 but it wasn't until 1916 that Edwin Hubble realised that the nebula also changes in brightness. The variations are such that even on images taken days apart structural changes can be observed.
NGC 2261 was chosen as the "first light" photograph on January 26, 1949 for the 200-inch (5.1 m) Hale reflecting telescope under the direction of American astronomer Edwin Powell Hubble. At the time, the newly constructed Hale telescope was the largest telescope in the World and remained so until 1976.
Mercury reaches greatest elongation east on January 14th (19 degrees @ mag. -0.7). From northern temperate and equatorial locations the closest planet to the Sun can be glimpsed low down above the southwestern horizon for about the first 3 weeks of the month, with the visibility period about a week less for those located further south.
This is not a particular good elongation of Mercury; even on the day of greatest elongation it appears only 5 degrees above the horizon 45 minutes after sunset. From about January 9th to 12th, much more brilliant Venus is close by and aids in finding its more illusive neighbour.
Mercury's magnitude fades from -0.8 to 0.0 between January 1st and 20th. The planet reaches perihelion on January 21st when it's located 0.308 AU (approx. 46.1 million kilometres or 28.6 million miles) from the Sun. On January 30th, Mercury passes inferior conjunction.
During January, Venus becomes a brilliant evening object for observers located at northern latitudes. At the beginning of the month the planet is visible for about 45 minutes above the southwestern horizon but by months end the visibility increases noticeably with the planet setting over 2 hours after the Sun. At magnitude -3.9, Venus is unmistakable, a dazzling beacon of light that's so bright it's often reported as a hovering UFO! Venus is also visible from southern temperate latitudes this month but always appears low down above the western horizon. It sets just over 1 hour after the Sun.
The phase of the planet decreases slightly from 96% to 92% as the month progresses with its apparent size increasing marginally from 10 to 11 arc seconds. On January 22nd, the thin waxing crescent Moon passes 6 degrees north of Venus.
Earth reaches perihelion on January 4th at a distance of 0.98333 AU (approx. 147.096 million kilometres or 91.402 million miles) from the Sun (6:36 UT).
Mars remains an early evening object located towards the western / southwestern horizon. At the beginning of January, the planet sets about 3.5 hours after the Sun from northern locations and about an hour or so less for those located further south. The "Red planet" is moving direct and continues its rapid motion against the fixed background stars, spending the first part of the month in Capricornus before crossing the border into Aquarius on January 9th. It then remains here for the rest of the month.
Mars is continuing to distance itself from the Earth and it exceeds 2 A.U. (299.2 million kilometers or 185.9 million miles) on January 7th. As a result, the planet shines at only magnitude +1.1 and has an apparent diameter of less than 5 arc seconds - too small for any detailed telescopic observations.
On January 23rd, the waxing crescent Moon passes 6 degrees north of Mars.
Jupiter is now a spectacular object moving retrograde amongst the stars of Leo and closer to the Cancer border. The planet rises a couple of hours after sunset on January 1st and by months end is practically visible all night as it closes in on a February 6th opposition date. The current northern declination of Jupiter slightly favours Northern Hemisphere observers, but even from southern latitudes where the planet appears lower down it's still unmistakable due to its brightness.
During January, the apparent diameter of Jupiter increases from 43 to 45 arc seconds with the planet marginally brightening from mag -2.5 to -2.6. A pair of binoculars is all that's needed to reveal the planets disk although it's small. Also visible are Io, Europa, Ganymede and Callisto, the four large Galilean moons. As they orbit Jupiter they are constantly changing position. Sometimes all four are visible but on other occasions some or all of the satellites will be temporarily obstructed and hidden as they pass behind or in front of Jupiter's disk.
When viewed through a telescope, Jupiter is a stunning sight. Even a small 80mm (3.1 inch) scope will shows the main northern and southern equatorial cloud belts and other finer details on the planets disk. Larger telescopes reveal much more including smaller belts, ovals, festoons and of course the famous "Red Spot".
On January 8th the waning gibbous Moon passes 5 degrees south of Jupiter.
Saturn (mag. +0.7) is now an early morning object. It begins January moving direct amongst the stars of Libra rising more than 3 hours from the Sun from northern temperate latitudes and only slightly less for those located further south. The visibility period of "Ringed planet" increases as the month progresses with the planet rising a few minutes earlier each subsequent morning.
When viewed through a telescope Saturn is one of the outstanding objects in the night sky. Even a small refractor will show the planets rings with larger scopes displaying them in supreme glory along with subtle details on the planet's surface and many of its brighter moons also visible.
On January 16th, the waning crescent Moon passes 2 degrees north of Saturn.
Uranus is an evening object moving direct amongst the stars of Pisces. During January the planet is visible as soon as it's dark enough but now sets before midnight by months end.
Uranus is currently positioned about 15 degrees south and 20 degrees east of the centre of the "Great Square of Pegasus". It's bright enough to be easily spotted with binoculars or a small telescope and is also just about visible to the naked eye but this is a challenging task, requiring dark skies.
The almost first quarter Moon passes 0.6 degrees north of Uranus on January 25th and an occultation is visible from Southern Europe, North Africa and Russia (11:52 UT).
Neptune, mag. +8.0, located in Aquarius is visible for a short time after sunset during January. The planet appears low down above the western horizon. January represents the last chance to catch a glimpse of the most distant planet before it reaches solar conjunction in February. It's not visible with the naked-eye but can be seen with binoculars when the sky is dark enough.
On January 19th, an interesting conjunction occurs when Mars passes just 0.2 degrees south of Neptune (mag. +8.0). The pair should be visible in the same field of view through a small telescope of the order of 100mm (4-inches) low down above the western horizon as soon as it's dark enough.
The waxing crescent Moon passes 4 degrees north of Neptune on January 23rd.
The Quadrantids meteor shower peaks on night of January 3/4, 2015. At maximum around 120 meteors per hour can be seen, which is comparable to the other great annual meteor showers the Perseids and the Geminids. However, the Quadrantids has a narrow peak activity window lasting only a few hours and consequently is not as well observed. Prospects for this year's event are not so good as the almost full Moon in northern Orion will significantly interfere. Therefore, if you can glimpse even just a few of these illusive meteors it will be a fine start to the new astronomical year!
Meteor showers are named after the constellation (or nearby star) where the radiant is located, but you may have difficulty figuring out the associated region for the Quadrantids; the reason is that the constellation no longer exists.
Today, the Quadrantids radiant is located in the northern constellation of Boötes, not far from the tail of Ursa Major. When the shower was discovered by Adolphe Quetelet of the Brussels Observatory in the 1830s, the radiant was located in the now obsolete constellation of Quadrans Muralis, hence the name "The Quadrantids".
Quadrans Muralis was originally created by Joseph Jerome de Lalande in 1795. This constellation, located in what is now the northern part of Boötes, represents the mural quadrant, a wall mounted astronomical instrument he used for measuring star positions. Although no longer recognized by the International Astronomical Union (IAU), Quadrans Muralis is one of the more widely known obsolete constellations due to its association with the meteor shower.
Since the peak of the Quadrantids is exceedingly sharp compared to other major showers, then the stream of particles that produces the shower must be relatively narrow. The recently discovered asteroid 2003 EH1 was proposed by Dutch astronomer and NASA senior research scientist Peter Jenniskens as the parent body of the Quadrantids. The asteroid is likely to be an extinct comet and may even be related to the comet C/1490 Y1, which was observed by Chinese, Japanese and Korean astronomers some 500 years ago.
Along with the Geminids, the Quadrantids are the only major meteor showers not originating from a comet.
As we head into the New Year, comet Lovejoy (C/2014 Q2) remains superbly placed for observation as it continues to brighten into January. The comet that was discovered by Australian amateur astronomer Terry Lovejoy has so far exceeded expectations and has been well seen from southern and tropical latitudes. For most of December, although Lovejoy was just beyond naked eye visibility it was an easy binocular and small telescope target, moving northwesterly through the southern constellations of Puppis, Columba and Lepus. By Christmas Day, Lovejoy had brightened to magnitude +5.4 and therefore within naked eye visibility. It's expected to peak at about magnitude +4.5 during the middle of January.
Northern Hemisphere based observers haven't had much of a look at Lovejoy but that's going to change. During the last days of December it can be spotted low down above the southern horizon with visibility continually improving as it climbs higher each subsequent evening. From southern latitudes, Lovejoy remains observable in excellent condition until late January.
Location and star chart
Comet Lovejoy started December in Puppis moving on a northwesterly trajectory. It then passed into Columba on December 17th where it remains until December 27th before crossing the border into Lepus. It passes close by globular cluster M79 on December 29th. On January 2nd, the comet moves into the large constellation of Eridanus remaining there for a week before crossing into Taurus on January 9th. It's expected to be close to peak brightness at this time and hopefully a nice naked eye sight with a long tail. As it continues to head north, Lovejoy moves into Aries on January 16th, Triangulum on January 24th and the into Andromeda on the last day of the month. Although still bright enough to be seen with the naked eye, Lovejoy is predicted to have faded to magnitude +5.3 by the beginning of February.
Many comets are often seen at their best either above the western horizon just after sunset or above the eastern horizon just before sunrise. Lovejoy is different in that it's positioned almost on the opposite side of sky to the Sun and therefore visible for much of the night. Adding to the splendour; from about January 5th to 13th the comet passes about 15 degrees west of probably the most famous constellation of the sky, Orion "the Hunter".
Over the next few weeks it will be very interesting to follow Lovejoy. It's already brighter than originally predicted and could brighten even further still. As with all comets, they are extremely unpredictable objects where anything can happen - and often does - so keep watching!!
The finder charts below show the positions of comet Lovejoy from December 3, 2014 to January 11, 2015.
Lynx is home to the fascinating globular cluster NGC 2419. Although visually faint and small what makes NGC 2419 special is its distance; at 275,000 light-years it's one of the furthest known Milky Way globulars. In fact, twentieth century American astronomer Harlow Shapley nicknamed it "The Intergalactic Tramp" believing it to have possibly broken away from the Milky Way and headed off into deep inter galactic space. However, recent observations indicate Shapley hypothesis was incorrect and NGC 2419 is still gravitationally bound to the Milky Way just moving in a highly eccentric orbit.
NGC 2419 or Caldwell 25 was discovered by William Herschel on December 31, 1788. It's located 275,000 light-years from the Solar System and about 300,000 light-years from the galactic centre, almost twice as far away as the Large Magellanic Cloud. At such a distance it's estimated it will take about 3 billion years to complete a single orbit around the centre of the galaxy.
NGC 2419 is positioned 7 degrees north and slightly east of Castor (α Gem - mag. +1.58) the second brightest star in Gemini. About 4 arc minutes west of NGC 2419 is a mag. +7.2 star with a double star of mag. +7.9 a few more arc minutes further west. Even Herschel with his super telescopes of the time couldn't resolve NGC 2419 into stars. William Parsons, the 3rd Earl of Rosse, using his 72-inch (1.83 m) reflecting telescope at Birr Castle in Ireland - the largest optical telescope in the world at the time - was first the first to do so in 1850.
The major meteor event in December is the Geminids but there's another shower later in the month that's doesn't make quite as many headlines but on occasions can be quite good - the Ursids.
With the radiant located close to the North Pole Star, the Ursids are a Northern Hemisphere shower. They are much less dramatic than the Geminids with only about 10 meteors per hour visible but on several previous occasions they have shown significant bursts of activity and a re-occurrence may happen anytime.
This year's Ursid peak occurs on the night of December 22nd/23rd and the good news the Moon is new and therefore won't interfere.
The comet that sources and therefore responsible for the Ursid meteor shower is 8P/Tuttle (also known as Tuttle's Comet or Comet Tuttle). It has a period of 13.6 years and during the last perihelion on January 27, 2008 it was visible telescopically. The comet passed Earth at a distance of 0.25282 AU (37,821,000 km or 23,501,000 miles) on January 1, 2008 and anticipation was high that the 2007 and 2008 showers may produce much increased activity, but this was not to be. In the end only a small increase was noted.
The radiant for the Ursids meteors is located in the far northern constellation of Ursa Minor, "The Little Dipper". With a declination of +76 degrees, the Ursid radiant is circumpolar from most northern sites and conversely fails to rise from most southern sites. It is positioned just a few degrees northwest of Kochab (β UMi).
NGC 752 is a large spawling open cluster in the constellation of Andromeda. With an apparent magnitude of +5.7, it's visible to the naked eye from a dark site appearing as a large unresolved fuzzy patch of light. The cluster is one of the finest large open clusters in the sky and contains over 70 stars spread across a huge 1.25 degrees of apparent sky. Due to its size, NGC 752 is best observed with binoculars or through wide field telescopes at low powers.
NGC 752 is located 5 degrees south and slightly west of outstanding double star Almach (γ And - mag. +2.1), the third brightest star in the constellation. It was discovered by Caroline Herschel on September 29, 1783 although it was probably observed sometime before 1654 by Italian astronomer Giovanni Battista Hodierna. Caroline's brother William Herschel subsequently added it to his catalogue a couple of years later. It's best seen from northern latitudes during the months of October, November and December.
NGC 2360 is an open cluster visible with binoculars in the constellation of Canis Major. It was the first deep sky discovery made by Caroline Herschel - the younger sister of William Herschel - on February 26, 1783. She described it as "a beautiful cluster of pretty compressed stars near 1/2 degree in diameter." It's also known as Caroline's Cluster, Caldwell 58 and Melotte 64.
William included the cluster in his 1786 catalogue of 1000 clusters, crediting his sister as the discoverer. At magnitude +7.2, NGC 2360 is not visible to the naked eye but it's an easy binocular object and a fine sight through small telescopes. The cluster is positioned 8 degrees east-northeast of the brightest star in the night sky, Sirius (α CMa - mag. -1.47) and lies 3.5 degrees directly east of gamma CMa (γ CMa - mag. +4.1). At the western edge of NGC 2360 is an unrelated star, HD 56405 (mag. +5.5).
NGC 457 is the brightest open cluster in Cassiopeia and one of the finest objects of its type in the northern sky. At magnitude +6.4, it's just beyond naked-eye visibility but easily seen with binoculars and a beautiful sight through telescopes. The brightest cluster stars are arranged in prominent lines and curves lines appearing to resemble an Owl shape, hence the popular name "the Owl Cluster". It's located 7,900 light-years distant.
NGC 457 was discovered by William Herschel in 1787. Finding the Owl Cluster is easy; it's positioned two degrees south-southeast of eclipsing binary star system Ruchbah (δ Cas - mag. +2.7). This star is one component of the characteristic "W" asterism of Cassiopeia. The brightest star inside NGC 457 is Phi Cas (φ Cas - mag. +5.0). Despite not being a member of the cluster, this foreground star is visible to the naked eye. Together with another non-cluster star - seventh magnitude HD 7902 (HIP 6229) - they form the bright eyes of the Owl, greatly adding to the splendour of the view through backyard scopes.
NGC 457 is best seen from Northern Hemisphere latitudes during August, September and October. It appears high in the sky and even overhead from many locations. From latitudes greater than 32N, the Owl is circumpolar and never sets.
The Geminids or "Winter Fireworks" is widely regarded as the richest and most active of the annual meteor showers with this year spectacle peaking on night of December 13th/14th. During peak activity up to 120 meteors per hour - many of them bright - can be seen under perfect conditions. Of the other annual showers only the August Perseids come close to attaining such highs.
In 2013, the glare from a waxing gibbous Moon significantly interfered with the Geminids around peak time, but this year's prospects are more favourable; the last quarter Moon doesn't rise until after midnight on peak day. By keeping the Moon out of view the most intense period of the shower can be observed with little interference.
The Geminids are unusual in that the source object is an asteroid, 3200 Phaethon. Together with the Quadrantids, they are the only major meteor showers not originating from a comet. Phaethon has an unusual orbit that brings it closer to the Sun than any other named asteroid, although there are several unnamed asteroids that do approach closer. At perihelion - the point of closest approach to the Sun - Phaethon is only 0.14 AU distant and much closer to the Sun than innermost planet Mercury.
On the other side, at aphelion (the point of furthest distance from the Sun) Phaethon moves out to 2.4 AU and therefore beyond the orbit of Mars. It's perhaps a little strange that no cometary activity has ever been associated with Phaethon, but nevertheless the Earth passes through the dust field, resulting in the Geminids meteor shower.
Phaethon was the first asteroid to be discovered using images from a spacecraft. While investigating data from the Infrared Astronomical Satellite (IRAS), Simon Green and John Davies discovered Phaethon on October 11, 1983. Its diameter is only 5.1 kilometres (3.2 miles).
The Geminids radiant or the point in the sky where the meteors appear to emerge is very easy to find. At the time of peak activity it's located very close to Castor (α Gem), a multiple star system that has a combined apparent magnitude of +1.6 and one of the brightest stars in the sky. Even brighter at magnitude +1.1 and located only a few degrees southeast of Castor is Pollux (β Gem), the brightest star in Gemini.
Comet Lovejoy (C2014/Q2), the fifth comet to be discovered by Australian amateur astronomer Terry Lovejoy on August 17, 2014, has now brightened sufficiently to move with binocular range. As it continues to increase in brightness, it should soon be visible to the naked eye and is expected to peak at about magnitude +4.5 during the middle of January.
Since the comet is located quite far south of the celestial equator it's well placed for observation from southern and tropical latitudes during December. For those located at northern temperate latitudes it's not visible until the second half of the month but after that it's observable in excellent condition.
Location and star chart
Comet Lovejoy starts December in the constellation of Puppis moving in a northwesterly direction. It then passes into Columba on December 17th where it remains until December 27th before crossing the border into Lepus. The comet is expected during this time to increase from magnitude +7.6 to +5.2 and therefore move from binocular to naked eye range.
Over the next few months it will be very interesting to follow Lovejoy as it's already a couple of magnitudes brighter than originally predicted and could brighten even further still. As with all comets, they are extremely unpredictable objects where anything can happen - and often does - so keep watching!!
The finder chart below shows the positions of comet Lovejoy from December 3rd to December 29, 2014.
The Hyades is a very large loose naked eye open cluster located in Taurus that spans 5.5 degrees of sky, equivalent to 11 times the diameter of the full Moon. At a distance of 153 light-years it's the nearest open cluster to us - the Ursa Major Moving Group is closer but it's extremely scattered and more of a cluster like object than an open cluster. Consequently, the Hyades is one of the most studied open clusters of all.
The Hyades are easily found since they circle around first magnitude orange giant star Aldebaran (α Tau - mag. +0.87), the brightest star in Taurus. It's not unreasonable to assume that Aldebaran is a member of the Hyades, but it's not. The star is purely a foreground star; an interloper located only 65 light-years distant that happens to be in the same line of sight. As a naked-eye object, the Hyades have been known since prehistoric times.
The cluster is best seen from northern latitudes during the months of November, December and January.
Mercury remains unsuitably placed for observation for most of December. The planet is currently on the far side of the Sun, passing through superior conjunction on December 8th and staying out of view until the very end of the month. It then re-appears as a difficult early evening object low down above the west-southwest horizon from tropical and southern latitude locations.
For example, on December 31st from latitude 35S (approx. equal to Sydney, Cape Town and Santiago), Mercury shines at mag. -0.8 appearing only 4 degrees above the west-southwest horizon 30 minutes after sunset. Positioned a couple of degrees above Mercury is much more brilliant Venus. From Northern Hemisphere latitudes, the planet is too low down to be seen this month.
Mercury reaches aphelion on December 8th when it's located 0.467 AU (approx. 69.9 million kilometres or 43.4 million miles) from the Sun.
Venus is also an early evening object for observers in the tropics and Southern Hemisphere. It's visibility improves as the month progresses although the planet remains low down above the west-southwestern horizon. However, at magnitude -3.9 it's unmistakable due to its brilliance.
Venus starts the month amongst the stars of Ophiuchus before moving into Sagittarius on December 7th where it remains for the rest of the month. Since the planet is positioned in the southern section of the sky, it's currently not as well placed for observation from northern temperate locations. However, observers at these locations will be able to glimpse it at the very end of the month.
On December 27th, Venus reaches aphelion and is located 0.728 AU (approx. 109 million kilometres or 67.7 million miles) from the Sun.
Mars remains an early evening object during December although it's faded to magnitude +1.1. The planet is moving direct, spending the first few days of the month in Sagittarius before traversing the constellation boundary into Capricornus. From northern locations it sets about 3.5 hours after the Sun, slightly less for those located further south. To the naked eye, Mars appears somewhat like an unremarkable reddish star above the western horizon. Telescopically it appears small; spanning only 5 arc seconds in diameter and even large amateur scopes at high magnifications won't show much detail.
On December 12th, Mars reaches perihelion at a distance of 1.38 AU (approx. 206.6 million km or 128.4 million miles) from the Sun. When opposition occurs around perihelion time - the last occasion in 2003, the next 2018 - Mars appears brilliant. Its magnitude can reach -2.9 with an apparent size of around 25 arc seconds.
Later in the month (Dec. 25th) the waxing crescent Moon passes 6 degrees north of Mars.
Jupiter is located in Leo and continues to increase in brightness and apparent size as it heads towards opposition in February next year. The largest planet in the Solar System rises before midnight at the start of the month, improving by a couple of hours by months end.
During December, Jupiter brightens from magnitude -2.2 to -2.4 and it's apparent size increases from 40 to 43 arc seconds. The planet reaches its first stationary point on December 9th, which signals the start of the 2014-2015 opposition period. Afterwards it begins retrograde motion.
On December 12th, the waning gibbous Moon passes 5 degrees south of Jupiter.
Saturn is currently located amongst the dim stars of Libra. It passed through solar conjunction last month and subsequently re-appears towards the southeast before sunrise during December. The beautiful ringed planet currently shines at magnitude +0.7.
By months end Saturn rises more than 3 hours from the Sun from northern temperate latitudes and only slightly less for those located further south. On December 19th, the waning crescent Moon passes 1.5 degrees north of Saturn.
Uranus, mag +5.8, is now two months past opposition but still remains well placed for observation. During December, the seventh most distant planet from the Sun is visible as soon as it's dark enough until after midnight.
Uranus starts December moving retrograde in Pisces. It then reaches its second stationary point on the 22nd - signaling the end of this year's opposition period - after which direct motion is once more resumed. The planet is faintly visible to the naked eye under dark skies but if you can't spot it, it's easy with binoculars.
This month there are two Uranus-Lunar occultations. The first occurs on December 2nd at 00:01 UT and is visible from visible from the Arctic, eastern Alaska and western Canada. The second occurs on December 29th at 04:59 UT, visible from Alaska, northern Canada, Arctic Ocean and northeastern Russia.
Neptune, mag. +7.9, visible with binoculars and small telescopes is moving direct in Aquarius. The most distant planet in the Solar System is positioned a couple of degrees west of Sigma (σ) Aqr (mag. +4.8) and can be seen during the first half of the night.
On December 26th, the almost first quarter Moon passes 4 degrees north of Neptune.
The first item in the Caldwell catalogue is NGC 188 an open cluster located in the far northern constellation of Cepheus. It was discovered by John Herschel - the son of William Hershel - on November 3, 1831. He originally recorded it as h 34 in his 1833 catalogue and then included it as GC 92 in his subsequent General Catalogue of 1864. The cluster finally became NGC 188 in John L.E. Dreyer's New General Catalogue of 1888.
NGC 188 is the northernmost open cluster in the sky; it's positioned only 4.75 degrees from the North Celestial Pole. Located at such a northerly declination means the cluster is circumpolar from almost the entire northern hemisphere. It can be seen from the Southern Hemisphere but only from latitudes north of 5 degrees south. Even then it never climbs more than a few degrees above the northern horizon.