December 2013 Celestial Calendar c/o Dave Mitsky

[Big Dipper]

December 2013 Celestial Calendar & Observing Notes c/o Dave Mitsky
(calendar data also reproduced in our forum calendar).

*NB: Check out also the resources at the end of Dave's calendar for further reading/information*

All times unless otherwise noted are UT.

12/1 Saturn is 1.3 degrees north of the Moon, with an occultation visible from western Antarctica, at 10:00; Mercury is 0.4 degree south of the Moon at 22:00
12/3 New Moon (lunation 1125) occurs at 0:22
12/4 The Moon is at perigee, subtending 33 arc minutes from a distance of 360,067 kilometers (223,832 miles), at 10:00
12/6 Venus is 8 degrees south of the Moon at 0:00; Venus is at its greatest illuminated extent at 19:00
12/7 The earliest sunset of the year at 40 degrees north latitude occurs today
12/8 Neptune is 6 degrees south of the Moon at 17:00
12/9 First Quarter Moon occurs at 15:12
12/10 The Lunar X (the Purbach or Werner Cross), an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to occur at 1:05
12/11 Mercury is at the descending node today; Uranus is 3 degrees south of the Moon at 7:00
12/14 The peak of the Geminid meteor shower (100 to 120 per hour) occurs at 6:00
12/17 Full Moon (known as the Before Yule, Cold, Long Nights, and Oak Moon), the smallest of 2013, occurs at 9:28
12/18 Uranus is stationary at 2:00
12/19 Jupiter is 5 degrees north of the Moon at 7:00
12/20 The Moon is at apogee, subtending 29 arc minutes from a distance of 406,269 kilometers (252,444 miles), at 0:00; Venus is stationary at 20:00
12/21 Mercury is at aphelion today; Venus is at the ascending node today; the shortest day of the year at 40 degrees north latitude occurs today; winter solstice in the northern hemisphere occurs at 17:11
12/22 The peak of the Ursid meteor shower (10 per hour) occurs at 14:00
12/25 Last Quarter Moon occurs at 13:48
12/26 The Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to occur at 2:51; Mars is 5 degrees north of the Moon at 3:00
12/27 The Moon is 1.1 degrees north of the first-magnitude star Spica (Alpha Virginis), with an occultation visible from most of Antarctica and the Kerguelen Islands, at 3:00
12/29 Saturn is 0.9 degree north of the Moon, with an occultation visible from part of Antarctica and the Kerguelen Islands, at 1:00; Mercury is in superior conjunction at 7:00

Tycho Brahe, Johannes Kepler, Isaac Newton, and Arthur Eddington were born in December.

Giovanni Cassini discovered the Saturnian satellite Rhea on December 23, 1672.

December 14th’s Geminid meteor shower is compromised by a waxing gibbous Moon. The Geminids, which are associated with the Palladian asteroid, or possible cometary nucleus, 3200 Phaethon, have become the most reliable meteor shower of the year. Geminid meteors appear to originate from a radiant that’s just northwest of Castor (Alpha Geminorum). An article on the 2013 Geminids appears on page 50 and 51 of the December issue of Sky & Telescope. The Ursids, a normally minor meteor shower, peak on December 22. The radiant is located close to Kochab (Beta Ursa Minoris), some 15 degrees from the north celestial pole. A waning gibbous Moon will be present in the sky. For additional information on these two showers, see http://in-the-sky.org/news.php?id=20131214_12_100 and http://in-the-sky.org/news.php?id=20131222_12_100 respectively.

Information on Iridium flares and passes of the ISS, the Tiangong-1, the X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/

The Moon is 27.5 days old and is located in Libra on December 1 at 0:00 UT. It attains its greatest northern declination (+19.6 degrees) for the month on December 17 and its greatest southern declinations (-19.5 degrees) on December 3 and (-19.6 degrees) on December 31. Longitudinal libration is at a maximum of +7.0 degrees on December 10 and a minimum of -7.7 degrees on December 27. Latitudinal libration is at a maximum of +6.7 degrees on December 20 and a minimum of -6.7 degrees on December 6. Large tides will occur on December 3 through December 6. The smallest Full Moon of the year occurs on December 17. The Walther Sunset Ray is predicted to begin at 2:20 p.m. EST (19:20 UT) on December 24. Visit http://www.astronomyblogs.com/member/saberscorpx/?xjMsgID=50821 for tips on spotting extreme crescent Moons. Browse http://www.lunar-occultations.com/iota/ for information on upcoming lunar occultations. Times and dates for the lunar light rays predicted to occur this month are available at http://www.lunar-occultations.com/rlo/rays/rays.htm

The Sun is located in Ophiuchus on December 1. Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on December 1: Mercury (magnitude -0.6, 5.3", 89% illuminated, 1.27 a.u., Libra), Venus (magnitude -4.9, 37.3", 31% illuminated, 0.45 a.u., Libra), Mars (magnitude +1.2, 5.6", 91% illuminated, 1.66 a.u., Virgo), Jupiter (magnitude -2.6, 44.9", 100% illuminated, 4.39 a.u., Gemini), Saturn (magnitude +0.6, 15.4", 100% illuminated, 10.78 a.u., Libra), Uranus (magnitude +5.8, 3.6", 100% illuminated, 19.77 a.u. on December 16, Pisces), Neptune (magnitude +7.9, 2.3", 100% illuminated, 30.32 a.u. on December 16, Aquarius), and Pluto (magnitude +14.2, 0.1", 100% illuminated, 33.50 a.u. on December 16, Sagittarius).

During the evening, Venus can be found in the southwest, Uranus in the southeast, and Neptune in the south. Jupiter is the southeast and Uranus is in the west at midnight. In the morning, Mercury is located in the southeast, Mars in the south, Jupiter in the west, and Saturn in the southeast.

At mid-month, Venus sets at 7:00 p.m. local time, Mars rises at 1:00 a.m. local time, Jupiter rises at 6:00 p.m. and transits at 2:00 a.m. local time, and Saturn rises at 4:00 a.m. local time, for observers at latitude 40 degrees north.

For the first ten days of December, Mercury is visible during morning twilight. The speediest planet is 0.4 degree south of the Moon on December 1. Mercury is in superior conjunction on December 29.

During the course of the month, Venus decreases in illuminated extent from 31 to 5%, while its apparent size increases from 37.3 to 58.9 arc seconds. Venus shines at a maximum magnitude of -4.9 on December 6. At that time, it is 26% illuminated, subtends 41 arc seconds, and is 3.4 light-minutes distant.

Mars grows in apparent size to 6.8 arc seconds and brightens to magnitude 0.9 this month. The Red Planet passes less than one degree north of the fourth-magnitude star Eta Virginis on the mornings of December 17 and December 18. On December 26, Mars is six degrees south of the Moon. It’s situated about one degree south of the third-magnitude binary star Porrima (Gamma Virginis) on the mornings of December 27 through December 30.

Jupiter is just 15 arc minutes south of the fourth-magnitude star Wasat (Delta Geminorum) on the evenings of December 9 and December 10. The King of the Planets lies five degrees north of the waning gibbous Moon on December 19. Shadow transits by Callisto and Io occur on the night of December 17 and the morning of December 18 at 10:04 p.m. and 5:27 a.m. EST respectively. Browse http://skyandtelescope.com/observing/objects/planets/article_107_1.asp in order to determine transit times of Jupiter’s central meridian by the Great Red Spot. Data on the Galilean satellites is available at http://skytonight.com/observing/objects/javascript/3307071.html#

Saturn rises at approximately 3:30 a.m. local time by the end of the month. The Ringed Planet is occulted by the Moon from Antarctica on December 1 and December 29. Saturn’s rings are inclined by 21 degrees this month. For information on the five brightest satellites of Saturn, browse http://skytonight.com/observing/objects/javascript/3308506.html

Uranus is located about six degrees southwest of the fourth-magnitude star Delta Piscium this month. Uranus resumes direct or prograde (eastern) motion on December 18.

During December, Neptune can be found two degrees northeast of the fifth-magnitude star 38 Aquarii. The eighth planet sets in mid-evening this month.

Finder charts for Uranus and Neptune can be found at http://media.skyandtelescope.com/documents/Uranus-Neptune-2013.pdf and on page 81 of the August issue of Astronomy and page 50 of the October issue of Sky & Telescope. See http://www.curtrenz.com/uranep.html for additional information on the two outer planets.

The dwarf planet Pluto is not visible again until next year.

For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/

At this time, it seems likely that the nucleus of the so-called Comet of the Century, C/2012 (ISON), was disrupted during its passage around the Sun at the end of November and that little of it remains. Browse http://www.skyandtelescope.com/community/skyblog/observingblog/Comet-ISON-Upd... and http://www.isoncampaign.org/ for updates on the status of the comet. On the other hand, Comet C/2013 R1 (Lovejoy) has been putting on a fine display in the morning sky. It is easily visible through binoculars. The fourth-magnitude comet travels from Bootes to Hercules this month. Click on http://www.flickr.com/photos/47833278@N02/11120307954/ and http://freestarcharts.com/index.php/19-news-and-current-events/223-lovejoy-c-... for finder charts. Another morning comet, the recently discovered C/2013 V3 (Nevski), passes through Leo and Leo Minor during December. See http://in-the-sky.org/cometephem.php?obj=ck13v030 for more on this newly discovered object. Visit http://cometchasing.skyhound.com/ and http://www.aerith.net/comet/future-n.html for additional information on comets that are visible this month.

Asteroid 511 Davida shines at tenth magnitude, as it glides northwestward through southern Taurus this month. This large member of the main asteroid belt passes less than a degree southwest of the fourth-magnitude star Mu Tauri on December 31. For information on this year’s bright asteroids and upcoming asteroid occultation events respectively, consult http://www.curtrenz.com/asteroids and http://asteroidoccultation.com/

A wealth of current information on solar system celestial bodies is posted at http://www.curtrenz.com/astronomical

Browse http://astrocast.tv/ for an informative video on astronomical events taking place this month.

A free star map for December can be downloaded at http://www.skymaps.com/downloads.html

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on December 2, 5, 8, 11, 14, 16, 19, 22, 25, 28, and 31. Consult http://www.skyandtelescope.com/observing/objects/variablestars/Minima_of_Algo... for the times of the eclipses. For more on Algol, see http://stars.astro.illinois.edu/sow/Algol.html and http://www.solstation.com/stars2/algol3.htm

One hundred and five binary and multiple stars for December: Gamma Andromedae, 59 Andromedae, Struve 245 (Andromeda); Struve 362, Struve 374, Struve 384, Struve 390, Struve 396, Struve 400, Struve 419, Otto Struve 67 (Camelopardalis); Struve 191, Struve Iota Cassiopeiae, Struve 263, Otto Struve 50, Struve 283, Struve 284 (Cassiopeia); 61 Ceti, Struve 218, Omicron Ceti, Struve 274, Nu Ceti, h3511, 84 Ceti, h3524, Lambda Ceti, Struve 330 (Cetus); h3527, h3533, Theta Eridani, Rho Eridani, Struve 341, h3548, h3565, Tau-4 Eridani, Struve 408, Struve 411, h3589, h3601, 30 Eridani, 32 Eridani (Eridanus); h3478, h3504, Omega Fornacis, Eta-2 Fornacis, Alpha Fornacis, See 25, Xi-3 Fornacis, h3596 (Fornax); Struve 268, Struve 270, h1123, Otto Struve 44, h2155, Nu Persei, Struve 297, Struve 301, Struve 304, Eta Persei, Struve 314, Otto Struve 48, Tau Persei, Struve 331, Struve 336, Es588, Struve 352, Struve 360, Struve 369, Struve 382, Struve 388, Struve 392, Struve 410, Struve 413, Struve 425, Otto Struve 59, Struve 426, 40 Persei, Struve 434, Struve 448, Es277, Zeta Persei, Struve 469, Epsilon Persei, Es878 (Perseus); Struve 399, Struve 406, Struve 401, Struve 422, Struve 430, Struve 427, Struve 435, 30 Tauri (Taurus); Epsilon Trianguli, Struve 219, Iota Trianguli, Struve 232, Struve 239, Struve 246, 10 Trianguli, Struve 269, h653, 15 Trianguli, Struve 285, Struve 286, Struve 310 (Triangulum)

Notable carbon star for December: U Camelopardalis

One hundred deep-sky objects for December: NGC 891 (Andromeda); IC 342, K6, St23, Tom 5 (Camelopardalis); Be65, IC 1848, K4, Mel15, NGC 896, NGC 1027, St2, Tr3 (Cassiopeia); M77, NGC 788, NGC 835, NGC 864, NGC 908, NGC 936, NGC 955, NGC 958, NGC 1015, NGC 1016, NGC 1022, NGC 1042, NGC 1052, NGC 1055, NGC 1087, NGC 1094 (Cetus); IC 2006, NGC 1084, NGC 1140, NGC 1187, NGC 1199, NGC 1209, NGC 1232, NGC 1291, NGC 1300, NGC 1309, NGC 1332, NGC 1337, NGC 1353, NGC 1357, NGC 1395, NGC 1400, NGC 1407, NGC 1421, NGC 1426, NGC 1440, NGC 1452, NGC 1453, NGC 1461 (Eridanus); NGC 1079, NGC 1097, NGC 1201, NGC 1292, NGC 1316 (Fornax I Galaxy Cluster), NGC 1317, NGC 1326, NGC 1344, NGC 1350, NGC 1360, NGC 1365, NGC 1371, NGC 1374, NGC 1379, NGC 1380, NGC 1381, NGC 1387, NGC 1398, NGC 1404, NGC 1406, NGC 1425 (Fornax); Bas10, Cz8, IC 351, IC 2003, K5, Mel 20, M34, NGC 869, NGC 884, NGC 957, NGC 1023, NGC 1058, NGC 1161, NGC 1245, NGC 1275 (Perseus I Galaxy Cluster), NGC 1333, NGC 1342, NGC 1444, Tr2 (Perseus); M45 (Taurus); NGC 777, NGC 784, NGC 890, NGC 925, NGC 949, NGC 959, NGC 978A/B (Triangulum)

Top ten binocular deep-sky objects for December: M34, M45, Mel15, Mel20, NGC 869, NGC 884, NGC 1027, NGC 1232, St2, St23

Top ten deep-sky objects for December: M34, M45, M77, NGC 869, NGC 884, NGC 891, NGC 1023, NGC 1232, NGC 1332, NGC 1360

Challenge deep-sky object for December: vdB14 (Camelopardalis)

The objects listed above are located between 2:00 and 4:00 hours of right ascension.

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*Suggestions for further reading/information:*
Check out the following two sites (both are primarily UK-based) - each of which contain excellent celestial guides for the month ahead:

Astronomical Calendar
Astronomy.co.uk (site includes a short video highlighting some of the main celestial events for the month ahead).