December Moon at Apogee

   Our Moon reaches apogee, (greatest distance from Earth), on Wednesday December 12th. At that time the Moon will more or less be at a distance of 31.76 Earth diameters 251,765 miles (405,177 km) from the Earth.

   Does our Moon actually go around the Earth? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

   On the day of the apogee the 6-day old waxing crescent Moon, an hour after sunset local time (4:55 pm CST), will be over the southwestern horizon and joined by several planets. Over the southern horizon is the planet Mars. Neptune and Uranus are also shown however at 8th Neptune requires optical assistance or a camera to become visible, while Uranus at around 6th magnitude could be visible with binoculars or telescope.

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

December Moon at Descending Node


   Monday December 10th the 3.5-day old waxing crescent Moon will be crossing the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.
   
   
   

   On the day of the node crossing the 3.5-day old waxing crescent Moon will be over the southwest horizon about an hour after the Sun sets.

   
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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Thin Waxing Moon in Conjunction with Saturn

   Saturday evening December 8th the 1.6-day young waxing crescent Moon will be in conjunction with the outer ringed planet Saturn. The two will be within about 3o from each other. Joining the Moon and Saturn is the Dwarf Planet Pluto, and further to the east are the planets Uranus, Neptune, and Mars.

   Within the field of view of 7×50 binoculars, in addition to the Moon and Saturn, are several Messier Objects, M-22, M-25, and M-26. These may be a challenge to see given that they are low over the western horizon and by the time the sky is darker they will have set or are just about to set.

   
   
   
   
   
   
   
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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Moon Conjunction with Spica and Venus

   Monday morning December 3rd the 28-day old thin waning crescent Moon will be within 5o from the blue white star Spica in Virgo the Harvest Maiden, and about 2o from the inner planet Venus.

   
   
   

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Mars Reaches Eastern Quadrature

orbital-positions   Monday December 3rd the position of the planet Mars, with respect to the Earth and the Sun, places this planet at what is called eastern quadrature. At that orbital position Mars, and actually any outer planet, is at a 90 degree angle from the Earth as this graphic shows, and the banner graphic at the top of the page shows. Think first quarter Moon as that is a fair comparison of the relative positions of Earth, Sun, and Mars.

   At this position Mars follows the Sun across the sky from east to west as the Earth is rotating, meaning that Mars rises after the Sun and then sets after the Sun. Mars, with an apparent magnitude of 0.0, is about 2o from 8th magnitude Neptune.

   
   
   

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Sun Enters Ophiuchus

ophiuchus   Friday, November 30th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Scorpius the Scorpion and into the constellation of Ophiuchus the Healer. This is the true or actual position of the Sun as opposed to the pseudoscience of astrology which usually has the astrological Sun one constellation ahead or east from the Astronomical Sun’s position.

ophiuchus-scorpion   Ophiuchus is the 13th constellation of the zodiac (Astronomical) but does not appear in the astrological zodiac nor in the astrology column found in many newspapers. A constellation of either zodiac is defined the same way, using the ecliptic path. If the ecliptic passes through a constellation boundary then that constellation is a zodiac constellation. In the graphics I use the ecliptic path clearly crosses across the boundary for the constellation Ophiuchus the Healer.

   Ophiuchus is described in a mythology story as a healer. In one story following a mortal fight between Orion and Scorpius the Scorpion Ophiuchus kills the scorpion by stepping on it; extracts the venom from the scorpion; and then uses it to bring Orion back to life.
cadeuces   In Ophiuchus’s hands he is holding a long snake, the 2-part constellation of Serpens – Serpens Cauda (tail of the snake) and Serpens Caput (head of the snake). There are many stories about Ophiuchus and the snake including one where this is the origin of the symbol for medicine, the caduceus. However the caduceus is used primarily in the United States as the symbol for medicine, and is depicted as 2 snakes wrapped around a staff with wings. rodIf there is a connection with a medical symbol then it should be with the Rod of Asclepius, a staff with one snake.
   
   
   

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Moon in Conjunction with Regulus

   Thursday morning November 29th the 22-day old waning gibbous Moon will be 1-2o from the heart of Leo the Lion, the star Regulus. By sunrise the Moon and Regulus will be over the southern horizon. At about that time Venus, shining very brightly, is still close to Spica as the two rise a couple of hours before the Sun rises.
   This is also the time of the year when the winter circle of constellations (Taurus, Auriga, Gemini Twins, Canis Minor, Canis Major, and Orion) start showing up over the horizon during the late evening hours.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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