This is your monthly guide to observing the planets, celestial events, moon phases, this day in space history, NASA launches, and other astronomy resources.
Observing The Planets:
- Mercury (evening planet) will be lost in the glow of the sunset for most the month and return in the western sky about half an hour after sunset on December 29.
- Venus (morning planet, magnitude -4.2) is visible high in the east in the predawn sky.
- Mars (morning planet, magnitude +1.5, in Virgo) is visible in the east just before sunrise.
- Jupiter (morning planet, magnitude -2, in Leo) is visible in the eastern predawn sky.
- Saturn (not visible) is lost in the glow of the sunrise.
- Uranus (evening planet, magnitude +5.8, in Pisces) is visible high in the southeast. Visible most of the night.
- Neptune (evening planet, magnitude +7.9, in Aquarius) is visible high in the southeast in early evening.
Understanding Visual Magnitude: Magnitude is a scale for measuring the brightness of objects in the sky. The dimmer the object the greater the number. The brightest objects generally receive negative numbers. Venus can be as bright as magnitude -4.9, the full moon is generally -12.7 and the sun is -26.8.
Moon Phases & Celestial Events:
- December 3: Last Quarter Moon at 2:40 am CST.
- December 4: Jupiter is 1.8° north of the Moon.
- December 5: Moon is at apogee (farthest from Earth) at 9 am CST at a distance of 404,800 km with an angular size of 29.5′.
- December 5: Mars is 0.1° north of the Moon, occultation.
- December 7: Venus is 0.7° south of the Moon, occultation.
- December 7: Comet Catalina (C/2013 US10), the crescent Moon, and Venus will fit into a circle 5° in diameter.
- December 11: New Moon at 4:29 am CST.
- December 13-15: Geminid meteor showers. Peaks on the 14th. The greatest number should occur between midnight and dawn. Under dark conditions it could reach 120 meteors per hour. It will appear to radiate in the constellation Gemini.
- December 17: Neptune is 3° south of the Moon.
- December 18: First Quarter Moon at 9:14 am CST.
- December 19: Uranus is 1.2° north of the Moon, occultation.
- December 21: Winter Solstice at 10:48 pm CST. Winter begins in the Northern Hemisphere and summer begins in the Southern Hemisphere. This is the shortest day of the year in the North and the longest day in the South.
- December 21: Moon at perigee (closest to Earth) at 3 am CST at a distance of 368,417 km with an angular size of 32.4′.
- December 21: Mars is 4° north of Spica.
- December 22: Moon will be near the Pleiades at 8 pm CST.
- December 23: Aldebaran is 0.7° south of Moon, occultation.
- December 25: CHRISTMAS DAY!
- December 25: Full Moon at 5:11 am CST.
- December 31: Jupiter is 1.5° north of Moon.
The following missions are scheduled for December:
Date: December 11, 2015 – 7:12 am CST.
Mission: Landing of ISS Expedition 45/Soyuz TMA-17M
Description: ISS Expedition 45/Soyuz TMA-17M Deorbit Burn and Landing Coverage (Deorbit Burn Scheduled at 7:17 a.m. ET; Landing Near Dzhezkazgan, Kazakhstan Scheduled at 8:10 a.m. ET)
Date: December 15, 2015 – 5:03 am. CST.
Mission: Expedition 46 Launch to the International Space Station.
Description: NASA astronaut Tim Kopra, ESA astronaut Tim Peake, and Yuri Malenchenko of Roscosmos will launch to the International Space Station.
Launch Vehicle: Soyuz spacecraft.
Launch Site: Baikonur Cosmodrome, Kazakhstan.
Date: December 21, 2015.
Mission: Progress 62P Cargo Craft.
Description: The Progress resupply will bring supplies and fuel to the International Space Station.
Launch Vehicle: Automatic, unpiloted version of the Soyuz spacecraft.
Launch Site: Baikonur Cosmodrome, Kazakhstan.
Want to learn more about what goes on each week on the International Space Station? Watch NASA’s weekly Space to Ground video log.
This Day In Space History:
- December 2, 1971: Mars 3 was the first spacecraft to soft-land on Mars.
- December 2, 1974: Pioneer 11 flies past Jupiter.
- December 3, 1973: Pioneer 10 first Jupiter flyby.
- December 7, 1995: Galileo spacecraft arrives at Jupiter.
- December 14, 1962: Mariner 2 was first successful flyby of Venus.
- December 15, 1970: Venera 7 was the first spacecraft to soft-land on Venus.
- December 21, 1968: Apollo 8 launched the first manned craft to leave Earth’s gravity.
- December 23, 1672: Giovanni Cassini discovers Saturn’s moon Rhea.
- December 25, 1642: Isaac Newton was born.
- December 27, 1571: Johannes Kepler was born.
- December 30, 2000: Cassini flies past Jupiter.
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