January Skies

by Dick Cookman

December 30, 2024

Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, January Moon

Focus Constellations: Ursa Major, Draco, Ursa Minor, Cepheus, Cassiopeia, Camelopardalis, Lynx, Cancer, Gemini, Orion, Taurus, Auriga, Perseus, Andromeda, Pegasus, Pisces, Triangulum, Aries

Comet Journals

Comet C/2023 A3 (Tsuchinshan-ATLAS) has dimmed to 10-11th magnitude in Aquila and is retreating to the Oort Belt as it leaves the inner solar system. It is best observed with a 8’ or larger telescope low in the eastern predawn sky. No other visible comets exceed 12th magnitude, and no currently discovered candidates are expected to rise above that brightness until autumn.

Mars Landers

Mars rover evidence gathered in recent years supports a warm and wet ancient planetary climate.

Where did the water come from and where did it go?

Alexandra Becker reports on marsdaily.com that a research team with Rice University professors Rajdeep Dasgupta and Kirsten Siebach, postdoctoral research associate Duncan Keller, graduate students Jackson Borchardt and Julin Zhang and Patrick McGovern of the Lunar and Planetary Institute employed advanced thermal modeling to reconstruct the thermal state of Mars’ crust during the Noachian and early Hesperian periods. “…variations in Mars’ crustal thickness during its ancient history may have influenced the planet’s magmatic evolution and hydrological systems.” “The research, published in Earth and Planetary Science Letters, suggests that the thick crust of Mars’ southern highlands formed billions of years ago generated granitic magmas and sustained vast underground aquifers, challenging long-held assumptions about the red planet’s geological and hydrological past. The study, led by Rice University’s Cin-Ty Lee, demonstrates that the southern highlands’ thick crust – up to 80 kilometers in some areas – was hot enough during the Noachian and early Hesperian periods (3-4 billion years ago) to undergo partial melting in the lower crust. This process, driven by radioactive heating, could have produced significant amounts of silicic magmas such as granites and supported subsurface aquifers beneath a frozen surface layer.”

Meteor Showers

The major January northern hemisphere meteor shower is the Quadrantid Shower, named after an obsolete constellation. The radiant is in northern Bootes which rises in the north-northeast after 9:00PM EST. The Quadrantids are best seen well before sunrise. Lunar glare will be absent as the waxing crescent Moon sets well before midnight.

• January 4: Quadrantids, Active Dec. 28-Jan. 12, Radiant 15h20m +49°, ZHR 120, 41 km/sec., Waxing Crescent Moon, Progenitor: Asteroid 2003 EH.

Planet Plottings

Mercury (0.3 to -0.9) in Ophiuchus and Capricornus is the only planet restricted to predawn skies in January. It is best observed in southeastern skies in early January, then descends deeper in the glow of sunrise, disappearing in late January as it approaches superior conjunction with the Sun on Feb. 9. Hesperus and Phosphorus were the ancient Greek names for the evening and morning stars. This winter, Venus (-4.3 to -4.5) in Aquarius and Pisces is Hesperus and, come summer, it will be Phosphorus. It reaches greatest eastern elongation at midnight, Jan. 9, when it is 47° from the Sun, the largest separation of the year. Saturn (+1.1) in Aquarius and Venus will be 3.0° apart on the 22nd. The waxing crescent Moon passes Mercury on the 1st, Venus on the 3rd, and Saturn on the 4th. Saturn, best viewed in early January when it sets at 10:00PM EST, is farther above the horizon than at its 8:00PM setting on the 31st. The waxing crescent Moon passes Neptune (+7.9) in Aquarius on the 5th and the waxing gibbous Moon passes Uranus (+5.7) in Aries and Jupiter (-2.2 to -2.0) in Taurus on the 9th and 10th respectively. Mars (-1.2 to -1.4 to -1.1) in Cancer and Gemini is closest to Earth on the 12th. It is 0.2° N from a waning gibbous Moon at 11:00PM EST on the 13th. The waning crescent Moon passes Mercury on the 28th and Saturn on the 31st. Mars opposition is on the 15th. Its brightness (magnitude -1.4) exceeds any since Dec. 2022, and equals Sirius, the brightest star in the nighttime sky. Numerous surface details are evident in telescopes with diameters of 8”+. Observers will have to wait until the opposition of 2027 for comparable telescopic views.

January Moon

The New Moon of January is in Scorpius on the 1st at 1:21AM EDT. This New Moon marks the start of Lunation 1262 which ends 29.59 days later with the New Moon on January 29. The Full Moon on the 13th occurs at 5:27PM EST in Libra. It is the Moon after Yule or Old Moon. Colonial Americans called it the “Winter Moon”. To the Celts it was the “Quiet Moon”, and it is the “Holiday Moon” for the Chinese. Medieval English thought of it as the “Wolf Moon”, and the Anishinaabe (Odawa and Ojibwe) people of northern Michigan recognize it as “Gichimanidoo-giizis” (Great Spirit Moon). Ontario’s Earth Haven Farm presents cultural teachings of the Mississauga branch of the Anishinabek Nation. They explain the cycle of life and nature of the 13 Grandmother Moons. “The first moon of Creation is Spirit Moon, and is manifested through the Northern Lights. It is a time to honour the silence and realize our place within all of Great Mystery’s creatures.”

• Lunar perigee – Jan. 7, 7:01PM EST. The Moon is at 230,213 mi. (57.28 Earth radii).
• Lunar Apogee (maximum lunar distance) – Jan. 20 at 11:54PM EST. The Moon’s distance is 251,219mi. (63.39 Earth radii).

At 8:00AM EST on Jan. 4, the Earth is at perihelion, its closest annual approach to the Sun. It may seem counterintuitive that this occurs in northern hemisphere winters until we remember that “THE REASON FOR THE SEASONS IS THE TILT”. On the northern hemisphere winter solstice ( Dec. 21, 2024), Earth’s axis was tilted away from the Sun, providing the least direct sunlight of the year to the northern hemisphere. Regions located at 23.5°S latitude basked under the direct rays of the Sun, the southern hemisphere summer solstice!