December 2019

 

During the first three weeks of the month, the Sun is travelling eastwards through the constellation of Ophiuchus and crosses the border into Sagittarius at around 17h on the 18^th. The earliest sunset of the year is on the 12^th, and the latest sunrise is on the 31^st. Between them lies the Winter Solstice, which this year takes place on December 22^nd at 04h21. The Earth-Sun distance at this time is 147,160,039 km. The Earth’s north pole is tilted as far away as it can be from the Sun (23.43681°) and this day is the official start of winter, a season which lasts 88.98 days in the northern hemisphere, and of course summer in the south.

 

The Moon

The Moon is at apogee, its furthest from the Earth at 04h (diameter 30minutes of arc), on the 18^th at 20h00; and at perigee, its nearest to the Earth, on the 4^th at 08h00.(diameter 32minutes of arc)

 

First Quarter Moon, on the 4^th at 06h59, is in the constellation of Aquarius.

 

Full Moon at 05h13 on the 12^th is in the constellation of Taurus, and is one of the highest full moons of the year. Unfortunately this Full Moon will interfere greatly with the most prolific meteor shower of the year, the Geminids which peak on the 13/14^th.

 

The Last Quarter Moon on the 19^th, occurs at 04h58 in the constellation of Virgo, midway between Regulus in Leo and Spica (alpha Virginis), brightest star in Virgo.

 

December’s New Moon in Sagittarius occurs at 05h14 on the 26^th , when an annular eclipse takes place. The path of annularity starts in eastern Arabia, crosses the southern tip of India, crossing the East Indies, northern Borneo and the southern Philippines, and finishes in the central Pacific Ocean. A partial eclipse is visible for eastern Africa and the Middle East, much of Asia and northern Australia. Unfortunately, Southern Australia, Western Europe and the Americas see nothing of this eclipse.

 

It may be possible to see Earthshine on the waning crescent from the 21^st to the 25^th, and on the waxing crescent Moon’s dark hemisphere on the first two, and last five days of the month.

 

The Planets

 

At the beginning of December, Mercury rises just after 06h, a couple of hours before the Sun rises, so this is the best time to see the elusive planet. Look very low down in the SE sky at around 008h in the bright morning twilight, but beware of the Sun, which rises shortly afterwards, if you are using binoculars. The planet lies only a couple of degrees above the horizon. During the rest of December, the planet is too close to the Sun to be observed.

 

 

Venus may be seen shining resplendently low in the SW as evening twilight fades. The planet is moving eastwards from Sagittarius to Capricornus. It is in conjunction with Saturn on the 11^th, and is 1° south of Pluto on the 15^th (= the brightest and the faintest of the 9 planets!, Venus shining at magnitude -4, Pluto at a faint +14). When Venus shines brightly as the ‘Evening Star’ in December, people wonder whether they are seeing the ‘Star of Bethlehem’ as of old. Use the Menu to find the page in these Sky Notes devoted to the ‘Star of Bethlehem’ for possible explanations. During the evening of the 28^th, the thin waxing crescent Moon with earthshine, may be seen approaching Venus, when at 17h, the Moon lies 5° to the lower right of the planet within 10° of the horizon in the SW. The next night the two objects are 6° apart but the Moon lies to the east (left) of Venus. This encounter takes place in the faint constellation of Capricornus and will be a pretty sight to behold if the weather behaves itself!

 

Mars is a morning object in Libra throughout the month. During December it rises some three hours before the Sun. The planet is at a great distance from the Earth, and so is not the brightest of planets at this time. Indeed, its visual magnitude is +1.6, which is the same magnitude at the star El Nath (beta Tauri), the star marking the northern horn of the Bull. At 07h on the morning of the 23^rd Mars and the waning crescent Moon with earthshine, lie 4° apart in the SE sky, at an altitude of 12°; both are parallel with the horizon. Below them the first few stars of Scorpius are making their appearance.

 

Jupiter is lost in the evening twilight throughout December and is in conjunction with the Sun on the 27^th.

 

Saturn sets two hours after the Sun on the 1^st, and only one hour after it on New Year’s Eve. The planet is low in the constellation of Sagittarius, and you must scan low in the SW at around 17h to spot it. Saturn is not excessively bright; its magnitude this month is around +0.6, which is a little fainter than the star Procyon in the constellation of Canis Minor (the Little Dog). Use binoculars to scan for Saturn. On the evening of the 27^th the hairline waxing crescent Moon and Saturn lie 3° apart, low in the SW, 5° above the horizon at 16h in the twilight, and should look good in the same binocular field.

 

Uranus culminates (crosses the S horizon). The planet lies in Aries, near to this constellation’s border with Cetus and Pisces. It culminates at around 20h during this month. It lies some 8° below Sheratan (beta Arietis)

A star chart showing the position of Uranus is to be found on the ‘REMOTE PLANETS’ page. Uranus is on the threshold of naked eye visibility at visual magnitude +5.72.

 

Neptune culminates (crosses the S meridian) at around 17h mid-month. It lies in the constellation of Aquarius and has a current magnitude of +7.9. The planet lies 1° to the west (right) of the 4^th magnitude star phi Aquarii. Use the star chart on the REMOTE PLANETS page to identify this remote world.

 

 

The maximum of the Geminid meteors takes place on the 14^th at 14h00. Geminids may be seen from the 4^th to the 17^th, and this year, the time of Maximum is  unfavourable because of the proximity of the Full Moon. This ‘Shooting Star Shower’ is the richest of the annual showers. (Weather permitting of course!)  The bright shooting stars are associated with asteroid (dwarf planet) 3200, Phaethon, the remains of a spent comet. Geminids tend to be most numerous around 02h00 when Gemini, their point of origin, is almost overhead. On good nights it is possible to see up to 100 meteors an hour. This shower produces a good proportion of bright events.

 

Peaking overnight on the 22^nd/23^rd and23^rd/24^th is the Ursid meteor shower (fragments of comet Tuttle), which produces about 10 meteors an hour, with occasional outbursts resulting in a greater number. Conditions this year are very favourable as the Moon is a waning crescent giving little light. The radiant (point of origin) of the meteors is in Ursa Minor, The Little Bear, some 12° from the celestial North pole.

 

Constellations visible in the south around midnight, mid-month, are as follows: Lepus the Hare, Orion, Taurus and Auriga the Charioteer.

All times are GMT     1° is one finger width at arm’s length.

 SUMMARY

The phenomena of the month : DECEMBER 2019
Times are given in UT for SCARBOROUGH (0° 25' 0" W, 54° 16' 3" N, zone 0 - UNIVERSAL TIME).

 

Date Hour Description of the phenomenon
yyyy mm dd hh:mm

2019 12 01  14:38   Opposition of the asteroid 97 Klotho with the Sun (dist. to the Sun = 1.985 AU; magn. = 9.9)

2019 12 02  04:42   Minimum of the variable star Algol (beta Persei)

2019 12 02  18:02   Maximum of the variable star eta Aquilae

2019 12 02  22:23   Close encounter between Venus and M 22 (topocentric dist. centre to centre = 0.8°)

2019 12 04  06:58   FIRST QUARTER OF THE MOON

2019 12 05  01:31   Minimum of the variable star Algol (beta Persei)

2019 12 05  04:09   Moon at apogee (geocentric dist. = 404446 km)

2019 12 05  12:31   Maximum of the variable star delta Cephei

2019 12 05  18:10   Beginning of occultation of 33 Psc (magn. = 4.61)

2019 12 05  19:15   End of occultation of 33 Psc (magn. = 4.61)

2019 12 07  17:45   Minimum of the variable star beta Lyrae

2019 12 07  22:20   Minimum of the variable star Algol (beta Persei)

2019 12 08  03:29   Close encounter between Jupiter and M 8 (topocentric dist. centre to centre = 1.0°)

2019 12 09  11:20   Meteor shower : Monocerotids (2 meteors/hour at zenith; duration = 20.0 days)

2019 12 09  22:16   Maximum of the variable star eta Aquilae

2019 12 10  03:08   Maximum of the variable star zeta Gemini

2019 12 10  19:09   Minimum of the variable star Algol (beta Persei)

2019 12 10  20:22   Opposition of the asteroid 28 Bellona with the Sun (dist. to the Sun = 2.472 AU; magn. = 10.4)

2019 12 10  21:18   Maximum of the variable star delta Cephei

2019 12 11  09:25   Close encounter between Venus and Saturn (topocentric dist. centre to centre = 1.8°)

2019 12 12  02:11   Beginning of occultation of 106 Tau (magn. = 5.28)

2019 12 12  03:12   End of occultation of 106 Tau (magn. = 5.28)

2019 12 12  05:12   FULL MOON

2019 12 12  10:16   Meteor shower : Sigma Hydrids (3 meteors/hour at zenith; duration = 12.0 days)

2019 12 13  04:16   Close encounter between the Moon and M 35 (topocentric dist. centre to centre = 2.0°)

2019 12 13  06:44   Beginning of occultation of 7-eta Gem, Propus, (magn. = 3.35)

2019 12 13  07:09   End of occultation of 7-eta Gem, Propus, (magn. = 3.35)

2019 12 13  15:00   Close encounter between Venus and Pluto (topocentric dist. centre to centre = 1.1°)

2019 12 13  15:58   Minimum of the variable star Algol (beta Persei)

2019 12 14  14:20   Meteor shower : Geminids (120 meteors/hour at zenith; duration = 12.0 days)

2019 12 15  02:57   Beginning of occultation of 10-mu2 Cnc (magn. = 5.30)

2019 12 15  04:09   End of occultation of 10-mu2 Cnc (magn. = 5.30)

2019 12 16  05:59   Close encounter between Mercury and Antares (topocentric dist. centre to centre = 5.0°)

2019 12 16  06:06   Maximum of the variable star delta Cephei

2019 12 16  08:38   Meteor shower : Coma Berenicids (3 meteors/hour at zenith; duration = 11.0 days)

2019 12 16  12:48   Minimum of the variable star Algol (beta Persei)

2019 12 17  02:31   Maximum of the variable star eta Aquilae

2019 12 17  08:01   Close encounter between the Moon and Regulus (topocentric dist. centre to centre = 2.9°)

2019 12 18  20:30   Moon at perigee (geocentric dist. = 370265 km)

2019 12 18  23:41   End of occultation of 3-nu Vir (magn. = 4.04)

2019 12 19  04:57   LAST QUARTER OF THE MOON

2019 12 19  09:37   Minimum of the variable star Algol (beta Persei)

2019 12 20  06:43   Maximum of the variable star zeta Gemini

2019 12 20  06:58   Meteor shower : Dec. Leo Minorids (5 meteors/hour at zenith; duration = 61.0 days)

2019 12 20  16:20   Minimum of the variable star beta Lyrae

2019 12 21  08:11   Comet 289P Blanpain at its perihelion (dist. to the Sun = 0.961 AU; magn. = 6.0)

2019 12 21  14:54   Maximum of the variable star delta Cephei

2019 12 22  04:19   WINTER SOLSTICE

2019 12 22  06:26   Minimum of the variable star Algol (beta Persei)

2019 12 22  22:37   Meteor shower : Ursids (10 meteors/hour at zenith; duration = 9.0 days)

2019 12 24  06:46   Maximum of the variable star eta Aquilae

2019 12 25  03:15   Minimum of the variable star Algol (beta Persei)

2019 12 26  05:13   NEW MOON (annular eclipse of the Sun not visible in SCARBOROUGH)

2019 12 26  23:42   Maximum of the variable star delta Cephei

2019 12 27  18:27   CONJUNCTION between Jupiter and the Sun (geoc. dist. centre to centre = 0.1°)

2019 12 28  00:04   Minimum of the variable star Algol (beta Persei)

2019 12 30  03:52   Opposition of the asteroid 69 Hesperia with the Sun (dist. to the Sun = 2.483 AU; magn. = 10.4)

2019 12 30  05:00   Mercury at its aphelion (distance to the Sun = 0.46671 AU)

2019 12 30  10:18   Maximum of the variable star zeta Gemini

2019 12 30  20:53   Minimum of the variable star Algol (beta Persei)

2019 12 31  11:01   Maximum of the variable star eta Aquilae 

 

(Using Coelix Software)