The night sky in January 2020

posted 31 Dec 2019, 07:45 by Pete Collins
by Anne Holt

Sunrise   1st:   08.24        31st:  07.56
Sunset    1st:  15.59         31st:  16.48

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

Earth is at perihelion on Jan 5th, when it is 147,091,144  km  (0.98 AU) from the Sun.

Full Moon:  10th at 19.21
New Moon:  24th at 21.42

Lunar apogee:   2nd at 01.31   (404,578 km)
Lunar perigee:  13th at 20.22   (365,963 km)
Lunar apogee:  29th at 21.29   (405,389 km)

The time between 2 successive Lunar perigees or apogees is known as an anomalistic month, therefore we have a complete one in January.

January's full Moon is known as the Wolf Moon, because this is the time when these animals are said to howl most.  Other names are the self explanatory Moon after Yule, the Old Moon, the Ice Moon, the Spirit Moon and the Chinese Holiday Moon.

Highlights

There still isn't much to write about, we have plenty of astronomical darkness - a few minutes over 12 hours on 1st and an hour less by 31st.  Venus is shining brightly in the early evening but the rest of the naked eye planets are very poorly placed, either low in the morning sky or not visible at all for most of the month.  The outer, fainter, ice giants are much better positioned in the evening sky, especially in early January.  There are a few circumpolar comets around but probably nothing approaching naked eye, or even binocular, brightness.
The one major meteor shower won't be affected by moonlight but it has only a very short peak, around dawn.
There is a partial Lunar eclipse on 10th, but the Moon only passes through the outer part, the penumbra, of the Earth's shadow so the darkening will be barely noticeable, especially if the sky is hazy.  From Manchester the eclipse begins at 17.07, when the Moon is only 8.6 degrees above the horizon.  Maximum cover, 86%, is at 19.10 at an altitude of 25.3 degrees and it finishes at 21.12, when the Moon has risen to 42.5 degrees.


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

Mercury:  in Sagittarius,  mag -0.9
Not visible for much of the month. On 1st it appears only 4 degrees from the Sun and moves even closer as it approaches superior solar conjunction on 10th. It then becomes an evening object, moving away from the Sun but still too close to be visible. When it moves into Capricorn on 17th the separation is still only 4 degrees.  By 23rd it is on the horizon as the sky darkens and on 25th  the thin crescent Moon is 2.5 degrees below the planet in the still bright sky. On 31st it is 5 degrees above the horizon as the sky darkens, setting at 17.57, about 70 minutes after the Sun.

Venus:  in Capricorn,  mag -4.0
Now even more prominent in the evening twilight. On 1st it should be visible in the still bright sky, 14 degrees above the horizon around 16.00.  Its position improves even more during the month as it moves away from the Sun, and also because the angle of the ecliptic to the horizon is increasing.  On 12th, when it moves into Aquarius, the planet is at 18 degrees in the SW when it becomes visible soon after sunset.  On 27th it is only 5 arcminutes south of Neptune at around 17.00.  The pair should be visible in the same field of view of a telescope.
IMPORTANT:  DO NOT ATTEMPT TO LOOK AT THEM THROUGH A SCOPE UNTIL AFTER THE SUN HAS FULLY SET AT AROUND 16.40.
A few minutes after 17.00 the pair will be 24 degrees above the SW horizon.  On 27th and 28th the thin crescent Moon is also close by.  On 31st Venus is 25 degrees above the SW horizon at 17.00, setting at 20.34.

Mars:  in Libra, mag 1.6
A morning object, still low in the sky.  On 1st it rises at 05.00 and only reaches  12 degrees above the horizon by dawn.  It moves into Scorpio on 8th, still at the same altitude, and Ophiuchus on 16th, when it is slightly lower at 11 degrees.  On 20th the crescent Moon passes close to the planet, nearest while they are still below the horizon but still separated by only 6 degrees just before dawn.  Red supergiant Antares, the rival of Mars, is also close to the pair.  On 31st Mars rises at 04.43 and is slightly brighter at mag 1.3, but even lower - only getting to 10 degrees before the sky brightens.

Jupiter:  in Sagittarius, mag -1.8
Very low in the morning sky following solar conjunction at the end of December.  On 1st it isn't visible as it appears only 3 degrees from the Sun.  On 23rd the very thin crescent Moon is just over 3 degrees SE of the planet at dawn, very low in the SE.  On 31st Jupiter rises at 06.39 and is only 4 degrees above the horizon when the sky begins to brighten.

Saturn:  in Sagittarius, mag 0.5
Not visible this month. On 1st it is on the horizon at dusk, setting at 16.53. It is at solar conjunction on 13th, then becomes a morning object.  By month end it rises at 07.17, 40 minutes before the Sun, but is still just below the horizon as dawn breaks.

Uranus:  in Aries, mag 5.8
Still the best placed of the outer planets, well placed in the early part of the night for binocular and telescopic observation and imaging. On 1st it culminates, 48 degrees above the southern horizon, at 19.28.  By midnight it has sunk to 21 degrees in the SW.  On 4th, at around 18.00, the just past 1st quarter Moon passes 5 degrees south of the planet.  On 31st it culminates at 17.30, while the sky is still fairly bright, and is at 47 degrees in the SE as astro darkness begins, setting at 00.44.

Neptune:  in Aquarius, mag 7.9
Reasonably high in the early evening sky at the beginning of January.  On 1st it is at 29 degrees in the south at 17.32 and should be high enough for telescopic viewing or imaging until around 19.00.  By 21st it is only 21 degrees above the horizon as the sky darkens, setting at 20.49 and on 31st it is only 15 degrees in the SW at dusk, and sets at 20.12.

Dwarf Planets

Ceres:  in Sagittarius, mag 9.0
Not visible this month as it is at solar conjunction on the night of 13th/14th.  It moves into Capricorn on 29th and on 31st is still only 11 degrees from the Sun.

Pluto:  in Sagittarius, mag 15.1
Another one which appears very close to the Sun this month, at solar conjunction on 13th.

Haumea: in Bootes, mag 17.4
Quite well placed for astrophotography in the early hours. On 1st it rises at 00.19 and will be high enough from around 3am,  reaching 49 degrees in the SE by dawn.  By 31st it rises at 22.17 and culminates at the end of astro darkness, 52 degrees above the southern horizon.

Makemake:  in Coma Berenices, mag 17.3
Reasonably high around midnight this month.  On 1st it rises at 22.11 and gets to 21 degrees in the east by 01.00, reaching its highest point, 59 degrees, at 06.40.  On 31st it rises at 20.11, is at 21 degrees by 23.00 and culminates at 04.42.

Eris:  in Cetus, mag 18.8
The faintest and most distant of the currently recognised dwarf planets moves very slowly against the background stars.  It takes 558 years to make one orbit of the Sun so since the announcement of its discovery, 15 years ago, has only completed approximately 2.6% of one orbit.  It hasn't even moved to another constellation and won't do so for another 15 years.  It was at aphelion in 1977 and is now getting closer to the Sun, however it won't reach perihelion for another 236 years.  On Jan 1st it reaches its highest point, 34 degrees, in the south at 19.09.  By 31st it culminates before the sky is fully dark and is at 33 degrees as the sky darkens around 18.15.

A couple of asteroids reach opposition in January.  These are a much better target for imaging, not only are they much brighter than the distant Kuiper Belt objects, they also seem to move much more quickly around the sky, so appear to have moved more in pics taken a few days apart.

511 Davida,  starts the month in Cancer, at mag 10.00.  On 1st it culminates, 58 degrees in the south, at 01.30.  It moves into Gemini on 3rd and is at opposition on 13th when it is at mag 9.6 and at 60 degrees by 00.23.  By 31st it will  have faded to mag 10.1 and culminate at 23.03, slightly higher at 62  degrees.

5 Astraea;  in Cancer, mag 9.6.  The fifth asteroid to be discovered, 38 years after 4 Vesta, is slightly lower - maximum altitude 51 degrees on 1st.  It is at opposition on 21st, when it culminates, 52 degrees in the south, at 00.20, slightly brighter at mag 9.0.  On 31st it will have faded to mag 9.2 and culminate at 23.28, a couple of degrees higher in the south.

Comets

Still a few around, circumpolar so above the horizon all night, but faint - only suitable for imaging.

C/2017 T2 (PANSTARRS)  in Perseus,  could possibly be as bright as mag 8.3 but more likely around mag 10 - as always, various sources fail to agree.
On 1st it is at 61 degrees in the NE as the sky gets dark, reaching its highest point, 88 degrees in the north, at 20.52. It strays into Camelopardalis on 2nd and 3rd, then back into Perseus on 4th.  It continues its eastward motion and during the last few days of the month passes north of the double cluster.  By this time it should have brightened slightly (but may have faded), will be at 84 degrees in the NE at dusk and down to 21 degrees in the north as the sky brightens around 06.30.

Also circumpolar, but much fainter.

C/2018 N2 (ASSASSIN)  in Andromeda, mag around 12. Again quite high, 75 degrees in the SW at dusk on 1st and 57 degrees in the west as the sky darkens on 31st.

260P/McNaught: in Perseus, mag around 14.  On 1st it reaches 80 degrees in the south at 20.13.  On 31st, probably fainter at around mag 15.5,  is 76 degrees in the south at 19.00.

Recommended websites for more information and exact positions of all solar
system objects


and for news about comets

Meteor Showers

One promising shower and a couple of very minor ones.

Quadrantids:  active December 28th to Jan 12th, peak in the early hours of 4th, ZHR estimates vary, could be as low as 25 or as high as 200.  This shower has a very short peak of 4 to 6 hours, centred on 8am, so is best seen just before dawn. They are medium paced, medium bright meteors often leaving trails, the shower often includes some fireballs. The parent body is asteroid 2003 EH1, thought to be a former comet.
The name Quadrantids comes from the former constellation Quadrans Muralis, the wall mounted quadrant, which was not included when the IAU published its official list of constellations in 1922.  The location of the shower radiant now lies in Bootes.
On the morning of 4th the Moon sets around 1am, so will not interfere with pre dawn observing.

Minor showers:

Gamma Ursa Minorids, active 10th to 22nd, peak 19th/20th ZHR 3.  Slow moving meteors, again best seen just before dawn when the radiant is high.

Kappa Cancrids:  peak 10th.  Some activity reported in 2015 and 2016 but nothing since.  It might be worth looking this year.  The radiant is very close to that of the Antihelion Source but the Cancrids are much faster moving.

The ANT is active in January, the radiant moves through SE Gemini and then across Cancer.  ZHR 2-3.
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