This Week’s Sky at a Glance, 2024 Dec 7 – Dec 14
This Week’s Sky at a Glance, 2024 Dec 7 – Dec 14
The most inconspicuous of the zodiac constellations is faint Cancer the Crab, which is nestled between Gemini and Leo. In mythology, the crab was sent by the goddess queen Hera to distract Hercules while he was battling the Hydra. The crab was no match for the strongman’s stomp. Ancient Egyptians saw it as their sacred dung beetle, the scarab. In the first millennium BCE the Sun was in Cancer at the summer solstice, the time when it halts its northward motion and slowly starts heading south. This back and forth motion of the rising and setting Sun on the horizon was perhaps reminiscent of a crab sidling on a beach.
The constellation is recognized by a trapezoid of dim but naked eye stars as the crab’s body, with other stars representing the claws and legs. The trapezoid was also seen as a manger flanked by a pair of donkeys, Asellus Borealis and Asellus Australus. On a clear dark night we can see a hazy patch of hay within the manger, and binoculars reveal it as a beautiful star cluster called the Beehive, Praesepe (manger) or M44. Being near the ecliptic, the Moon and planets often pass through or near this cluster, and Mars will spend most of this month nearby. The Beehive was once used to forecast storms, for if it could not be seen it was hidden by light clouds at the front of a weather system. Binoculars reveal another star cluster, M67, less than a fist-width south of M44.
This Week in the Solar System
Saturday’s sunrise is at 7:50 and sunset will occur at 4:41, giving 8 hours, 51 minutes of daylight. Next Saturday the Sun will rise at 7:56 and set at 4:42, giving 8 hours, 46 minutes of daylight. We are into an approximate two-week period of the earliest sunsets for the year.
The Moon is at first quarter below Saturn on Sunday and it is just east of the Pleiades next Friday. Brilliant Venus can be seen in the southwest soon after sunset, slowly gaining altitude nightly and setting around 8 pm. Saturn is at its highest and best for observing by 6 pm, showing its rings nearly edge on. Jupiter is at opposition on Saturday, lording over the sky all night and attracting attention in the west-northwest an hour or two before sunrise. On Tuesday evening between 6:30 and 8:30 telescope users might see Jupiter’s Red Spot, its moon Io and Io’s shadow transiting the planet. Mars begins its retrograde motion this week and remains within a binocular view of the Beehive star cluster. I have been starting my day with views of this and Jupiter’s moons every clear morning. The Geminid meteor shower is at its peak over December 13/14, a worthy view despite the bright moonlight.
Tune in to the Sunday Night Astronomy Show at 8 pm on the YouTube channel and Facebook page of Astronomy by the Bay. The Fredericton Astronomy Club meets in the UNB Forestry-Earth Sciences building on Tuesday at 7 pm.