The night sky in January 2019

posted 31 Dec 2018, 06:06 by Pete Collins   [ updated 31 Dec 2018, 12:01 ]
by Anne Holt

Sunrise     1st:    08.24          31st:    07.56
 Sunset     1st:    16.00          31st:    16.49

Astronomical darkness
1st:   18.10  to  06.14          31st:  18.50  to  05.53

Earth is at perihelion (closest point to the Sun) on 3rd at 05.19, when it will be at a distance of 147,100 km.

New Moon:   6th at 01.28      Full Moon:  21st at 05.16

The January full Moon is known as the Wolf Moon because they were said to be particularly vocal at this time.  Other names are the Moon after Yule, the Old Moon, the Ice Moon and the Snow Moon.

On the morning of 21st we have a total lunar eclipse, visible from all the UK - at least from all the parts where the weather co-operates and keeps the sky cloud free.  The Moon will appear relatively large as it is only 14 hours and 43 minutes before perigee.

Highlights

We still have long periods of astronomical darkness in which to observe the beautiful winter skies, or, more likely, the horrible winter clouds. Venus and, to a lesser degree, Jupiter are bright in the pre-dawn sky and comet 46P Wirtanen is still around, higher but fainter, and we have a promising meteor shower not affected by moonlight.   The main events this month are the total lunar eclipse on 21st (early morning so set your alarm) and New Horizons' long awaited close encounter with a Kuiper Belt object on New Year's Day.

Constellations

There isn't much change in the prominent constellations since December, just that everything rises, or sets, a couple of hours earlier. Orion is now well above the horizon by 8pm at the start of the month, with Sirius rising at this time.  By month end, Sirius will rise at about 6pm.  Auriga, Gemini and Cassiopeia are all high in the sky. The Summer Triangle is now setting earlier as the Winter Hexagon rises. Taurus and the Pleiades are still very prominent and the spring constellation of Leo is above the south eastern horizon by 9pm.

Planets

The best time for seeing naked eye planets this month is in the early morning, especially near the beginning and end of the month, when they are joined by the crescent Moon.

Mercury:  in Ophiuchus, mag -0.4.  Very low in the morning sky, so not easily seen in January.  On 1st it rises at 07.14 and is only 2 degrees above the horizon at dawn. Its position deteriorates further as the month progresses. It moves into Sagittarius on 3rd and on 13th is separated from Saturn by only 1.8 degrees, about 20 minutes before Sunrise, but both are barely above the horizon and extremely difficult to see.  As always DON'T try looking for them through a scope or binoculars - it really will be unlucky 13th for you if you mistime it and catch the first rays of the rising Sun.   The planet reaches superior conjunction on 30th and can't be seen at all in the later part of the month.

Venus:  in Libra, mag -4.5.  Still shining brilliantly in the pre-dawn sky.  On 1st it rises at 04.15 and should be unmissable from around 5.30.  It reaches 19 degrees above the horizon by sunrise.  On the mornings of 1st and 2nd it is close to the waning crescent Moon.  It reaches greatest Western elongation on 6th, when it is 47 degrees from the Sun and 20 degrees above the horizon as the sky brightens. It moves into Ophiuchus on 15th, when it will be slightly lower, 16 degrees in the SE at dawn.   On the morning of 22nd it will be only 2.5 degrees from the 10 times fainter (but still very bright) Jupiter just before Sunrise. On 31st  it rises at 05.06, reaching only 12 degrees as the sky brightens.  

Mars:  in Pisces, mag 0.5.  An evening object, culminating in astronomical twilight and setting around 23.30 throughout January. On 1st it reaches its highest point, 35 degrees, at 17.24.  It continues to climb higher in the sky, crossing the celestial equator in early January.  On 12th the 35% Moon passes just over 6 degrees south of the planet at 18.00.  By 31st it is at 43 degrees in the south at 17.30, but fainter at mag 0.9.

Jupiter:  in Ophiuchus, mag -1.8.  A morning object whose position improves during the month.  On 1st it rises at 06.11 but only reaches 9 degrees in the south east before the sky brightens. On this day it forms a line with Venus, Mercury and the crescent Moon - though only Jupiter, Venus and the Moon are likely to be easily visible.  On 3rd the 6% Moon passes 2.3 degrees north of the planet. On 31st, when it is marginally brighter at mag -1.9, it rises at 04.42 and is at an altitude of 12 degrees as dawn breaks.  On this day the crescent Moon is midway between Venus and Jupiter.

Saturn:  in Sagittarius, mag 0.5. At Solar conjunction on 3rd so not visible as it is only 1 degree from the Sun.  The apparent separation does increase during the month but it is below the horizon at dawn until 19th.  On 31st it is still only at an altitude of 2 degrees as the sky begins to brighten.

Uranus:  in Pisces, mag 5.8.  An evening object, well placed for binocular observation before midnight in the first part of January.  On 1st it culminates at 19.10,  in astronomical darkness, 46 degrees above the southern horizon.  At the start of the month it appears to be moving westwards against the background stars (retrograde) but on 7th it resumes prograde motion.  By mid month it is culminating during astronomical twilight but is still high in the sky for about 4 hours. On 31st it reaches 45 degrees in the south at 18.00, as the sky darkens, setting soon after midnight.  It should be easily visible in binoculars, especially from a dark sky site, but a scope is needed to show the small blue/green disc.

Neptune:  in Aquarius, mag 7.9.  Visible through a scope, in the SE, as darkness falls in early January.  On 1st it is at 27 degrees in the south at 17.30, setting at 21.50.  On 18th it is 21 degrees above the horizon at dusk and by month end isn't easy to see, as it is at only 14 degrees as the sky darkens.  A decent amateur scope should show the planet as a small blue disc.

Dwarf Planets

Ceres:  in Libra, mag 8.9.  Should be a good photographic target, or maybe visible in large binoculars or a small scope, in the morning sky.  On 1st it rises at 03.48 and reaches 19 degrees by dawn. It moves into Scorpio on 31st, when it rises at 02.47 and gets to an altitude of 20 degrees before the sky brightens.  Because it is so small it will only appear as a point of light, even in a large scope.

The others are out of reach of even the largest amateur scopes but could be targets for experienced astrophotographers using good equipment and the 'spot the difference' technique used to discover Pluto.

Pluto:  in Sagittarius, mag 14.7.  Not visible this month as it is very close to the Sun.

Eris:  in Cetus, mag 18.8.  Much fainter but better placed for imaging. especially in the early part of January.  On 1st it reaches 34 degrees in the south at 19.06, an hour before the start of astro darkness, and sets at 01.01. On 31st it is at 32 degrees in the south as the sky darkens soon after 18.00, setting around 23.00.

Haumea: in Bootes, mag 17.4. On 1st it rises at 00.10 and reaches 50 degrees in the SE before the sky brightens.  From mid January it culminates in astro darkness - 52 degrees at 05.47 on 31st.

Makemake: in Coma Berenices, mag 17.1.  Rises at 22.00 on 1st, and culminates, at 60 degrees, a few minutes after astro darkness ends. On 31st it reaches this altitude at 04.36 while the sky is still fully dark.

Recommended websites for more info and full details of planetary positions:

Meteor Showers

One major shower in January.
Quadrantids, active Dec 28th to Jan 12th, peak on the night of 3rd/4th, ZHr 25 to 40, more according to some sources.  They all agree that this shower has a very short peak, about 6 hours, centred this year on 02.20, and is best seen between midnight and 4am, when the radiant is high in the sky.  They are medium paced, not especialy bright meteors not usually leaving trails, but sometimes including fireballs. They occur when the Earth passes through debris in the orbit of asteroid 2003EH1, thought to be a remnant of defunct comet C1490X1. The name is derived from the former constellation Quadrans Muralis, the mural (or wall mounted) quadrant, which disappeared when it was omitted from the IAU's list of officially recognised constellations in 1922. The location of the shower radiant is now part of Bootes. 

The antihelion source (ANT) is active in January.  These are meteors, not belonging to any specific shower, which have a radiant on the ecliptic, opposite the position of the Sun.  ZHR is given as around 3.

There are also 2 very minor showers for which not much information is available.

Kappa Cancrids peak on the night of 9th/10th. The radiant is very close to that of the ANT but meteors from the shower should be easily distinguishable as they are much faster moving.

Gamma Ursa Minorids, active 10th to 22nd, peak 18th, ZHR 3.  Slow moving meteors.


Comets

46P Wirtanen is past its best, recently discovered C2018V2 (Machholz- Fujikawa- Iwamoto) has disappeared behind the Sun and there are 2 much fainter ones which may be good photographic targets.

46P Wirtanen starts the month in Lynx at around mag 5.3.  It is circumpolar but best seen soon after midnight, when it reaches an altitude of 84 degrees in the north. On 2nd it moves into Camelopardalis and on 9th into Ursa Major.  Not easily seen in the latter part of the month, despite being almost overhead at 01.00 on 31st - it is expected to have faded to mag 8.3 by this time.

C2018L2(Atlas)  Starts the month in Hercules at mag 9.4 and may be visible in a small scope 22 degrees above the western horizon at around 17.30.  It moves into Sagitta on 2nd and Vulpecula on 9th.  Between 12th and 18th it should be above the horizon at both dawn and dusk, then it ends the month as a morning object slightly fainter at mag 9.8. On 31st it will be 26 degrees above the eastern horizon at dawn.

38P Stephan-Oterma. In Lynx, mag 9.9.  Circumpolar and visible (through a scope) for most of the night throughout January.   Starts the month a little to the west of Wirtanen, 77 degrees above the southern horizon at 2am, but the faster moving Wirtanen soon leaves it behind.  On 31st it is at 37 degrees in the NE at dusk and 33 degrees in the NW at dawn.

Comet co-ordinates and position charts can be found in the websites mentioned earlier, and also in www.cometwatch.co.uk

Special Events

We have a Total Lunar Eclipse on the morning of 21st. The partial phase begin at 03.33 with totality starting at 04.41 when the Moon will be 29.9 degrees above the horizon.  Totality ends an hour later at 05.43, still in astro darkness, when the Moon is about 9 degrees lower in the sky.  The last of the shadow leaves the Moon at 06.50.  The face of the Moon can be seen during totality, usually having a reddish or brown hue, even though it is completely in shadow.  This is because some of the Sun's light is refracted by the Earth's atmosphere, the blue end of the spectrum is more widely scattered leaving the red light to illuminate the Moon.  The actual colour depends on atmospheric conditions at the time of the eclipse.

And finally .....

Only a few hours into the New Year, at 05.33 on January 1st, after a journey of almost 13 years New Horizons will pass a Kuiper Belt Object at a distance of only 3,500 km - almost 4 times closer than it was to Pluto.  The KBO's designation is (486958) 2014MU69, but it has been given the unofficial (ie not recognised by the all powerful IAU) name of Ultima Thule - a name meaning beyond the borders of the known world, or a distant unknown region at the limit of travel and discovery.  It is about 6 billion miles from Earth and so small that it can't be seen as anything but a speck until New Horizons is almost at its closest.  The probe cannot receive and transmit data at the same time, so it will not begin sending any information back to Earth until about 4 hours after its closest encounter.  It will then take another 6 hours to reach us so, if all goes well, we might begin to learn about this tiny, distant icy world in the late afternoon of New Year's Day.   It will take about 2 years for all the data collected during the flyby to be sent back to Earth.
And New Horizons still has some fuel left, so that might not be the end of its story.
Comments