Embracing the Longest Night: Constellations, Star Clusters, Planets, and Celebrations of the Season

25/12/2024

As winter blankets the Northern Hemisphere, the night sky unveils a tapestry of celestial wonders that invite us to explore the astronomical phenomena defining this season. From the Winter Solstice to prominent constellations and planets, let's embark on a journey through the cosmos.

The Winter Solstice: An Astronomical Perspective

The Winter Solstice occurs around December 21st in the Northern Hemisphere and marks the point when the Sun reaches its southernmost position in the sky. This results in the shortest day and the longest night of the year. This event is a consequence of Earth's axial tilt of approximately 23.5 degrees relative to its orbital plane. As Earth orbits the Sun, this tilt causes varying angles of sunlight, leading to the changing seasons. In 2024 in Winnipeg, Manitoba, Canada the Winter Solstice will occur on Saturday, December 21, 2024 at 3:20 am CST.

Image from the article 'The December solstice is here. Here's how it works and why it starts winter and summer at the same time.' on Business Insider.

Interestingly, during the Northern Hemisphere's winter, Earth is near perihelion—the closest point to the Sun in its elliptical orbit. Despite this proximity, we mostly experience colder temperatures due to the oblique angle of sunlight, which spreads solar energy over a larger surface area. That being said, Earth's orbital speed increases near perihelion, causing us to move faster in our orbit during the winter months and giving those in the Northern Hemisphere a slightly shorter Winter and slightly longer Summer than those who live in the Southern Hemisphere. This increase in orbital speed near perihelion follows Kepler's Second Law of planetary motion, which states that a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. This means that a planet travels faster in its orbit when it is closer to the Sun (at perihelion) and slower when it is farther from the Sun (at aphelion).

Image from the article 'The December solstice is here. Here's how it works and why it starts winter and summer at the same time.' on Business Insider.

Winter Constellations and Asterisms

Winter nights unveil some of the most recognizable constellations and asterisms:

Orion: Dominating the winter sky, Orion is identifiable by the three stars forming his "belt"--Alnitak, Alnilam, and Mintaka. The four main stars outlining Orion's body are Betelgeuse (a red supergiant marking his right shoulder), Bellatrix (his left shoulder and a prominent antagonist in the Harry Potter series), Rigel (his left foot), and Saiph (his right knee). Below the belt lies the Orion Nebula (M42), a stellar nursery visible to the naked eye under dark skies.

Image from the article 'Orion the Hunter, the most recognizable constellation' on EarthSky.

Taurus: Home to Aldebaran, the bright red eye of the bull, Taurus is a prominent winter constellation that sits along the ecliptic, the apparent path the Sun takes through the sky.
Auriga: This pentagon-shaped constellation houses Capella, the sixth-brightest star in the night sky. Auriga is situated near the Milky Way, offering rich star fields for observation.
Winter Hexagon: Also known as the Winter Circle, this asterism connects six bright stars--Sirius in Canis Major, Procyon in Canis Minor, Pollux in Gemini, Capella in Auriga, Aldebaran in Taurus, and Rigel in Orion. It serves as a guide to locating several prominent constellations.

Image 1 from the article 'March: The Winter Hexagon' on Sky & Telescope.
Image 2 from the article 'Explore The Winter Hexagon' on Sky & Telescope.

Winter Triangle: The Winter Triangle is a smaller asterism within the Winter Hexagon. It is formed by connecting three prominent stars: Sirius, Procyon, and Betelgeuse (the bright red star marking Orion's shoulder). This striking triangular pattern lies near the centre of the larger hexagon and is easily recognizable in the winter sky.

Image from the article 'The Winter Triangle' on AstroBackyard.

Winter Star Clusters

Complementing these constellations and asterisms are several notable star clusters that shine brightly during winter nights:

Pleiades Star Cluster (Messier 45): Also known as the Seven Sisters, the Pleiades is a group of young, hot blue stars located near Taurus. Best viewed with binoculars, this open star cluster has been observed since ancient times and holds significance in various cultures.

Image from Davide De Martin & the ESA/ESO/NASA Photoshop FITS Liberator.

Hyades: Found in Taurus and approximately 153 light-years (47 parsecs) from our Sun, the Hyades cluster is the closest open star cluster to Earth. Its distinctive V-shaped formation is anchored by Aldebaran, though the red giant is not actually part of the cluster but lies along the same line of sight.
Beehive Cluster (Messier 44): Situated in Cancer, the Beehive Cluster (also known as Praesepe (Latin for "manger", "cot" or "crib"), M44, or NGC 2632) is easily visible to the naked eye under dark skies. It reveals a rich field of stars when viewed through binoculars or a small telescope.
Double Cluster (NGC 869 and NGC 884): Located between Perseus and Cassiopeia, the Double Cluster consists of two open clusters that appear as a hazy patch to the naked eye and resolve into a stunning array of stars that is one of my favourite sights through a telescope.
Orion Nebula (Messier 42): Found in the constellation Orion, the Orion Nebula is one of the most famous and brightest emission nebulae visible from Earth. A stellar nursery, it offers a breathtaking view of star formation regions, especially when observed with binoculars or a telescope under dark skies.

Image from NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team.

Planetary Highlights

This winter offers a spectacular lineup of planets gracing the night sky, providing excellent viewing opportunities from southern Manitoba in December 2024:

Jupiter: Reaching opposition on December 7, 2024, Jupiter dominates the night sky, shining brighter than all the stars at a magnitude of -2.8. Visible all night and high above the horizon, it can be found near the bright stars Capella, Betelgeuse, and Aldebaran, as well as the Pleiades and Hyades open star clusters. With binoculars or a small telescope, you can observe its four largest moons--Io, Europa, Ganymede, and Callisto—orbiting the giant planet.

Image from the article 'Earth-observing satellite captures rare photos of Jupiter and its moons' on Space.com.

Venus: Often referred to as the "Evening Star," Venus shines brilliantly in the evening sky after sunset, reaching a dazzling magnitude of -4.4 by the end of the month. In December, Venus will be visible low on the western horizon and ascend higher each evening as it moves through the constellations of Sagittarius, Capricornus, and Aquarius. It will remain a brilliant evening star through March 2025 and will reach its greatest elongation from the Sun in January 2025.
Mars: As it approaches opposition in early 2025, Mars becomes increasingly prominent. In December 2024, Mars rises earlier each night, glowing with its characteristic reddish hue in the evening sky. This provides an excellent opportunity to observe its surface features—such as polar ice caps and dark volcanic plains—through a telescope with a sufficiently large aperture.
Saturn: Gracing the evening sky, Saturn will be well above the eastern horizon after sunset and set several hours later. Its golden glow is a treat for observers. With a small telescope, you can admire its magnificent ring system and perhaps even glimpse some of its largest moons, like Titan. Saturn will remain visible in the evening sky for the rest of 2024 before disappearing into the sunset glare in February 2025.

Image from NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley).

Mercury: The closest planet to the Sun, Mercury reaches its greatest western elongation of 22 degrees from the Sun at 9 p.m. CST on December 24, 2024. This is an ideal time to spot Mercury in the morning sky before sunrise in the east. Like Venus, Mercury exhibits phases and appears as a crescent when viewed through a telescope, offering a unique sight for early risers. However, when observing Mercury, be cautious of the Sun's proximity. Even brief exposure to direct sunlight through binoculars or a telescope can cause serious eye damage.

Information in this section from: https://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/

Cultural Celebrations Around the Winter Solstice

The Winter Solstice has been a time of celebration across various cultures:

Hanukkah: Also known as the Festival of Lights, Hanukkah is an eight-day Jewish celebration that usually occurs in December. It commemorates the rededication of the Second Temple in Jerusalem and is marked by lighting candles on a menorah each night.

Generated with DALL·E.

Dongzhi Festival: Celebrated in East Asian cultures, particularly in China, the Dongzhi Festival takes place on the Winter Solstice, marking the arrival of winter and the longest night of the year. Families gather to enjoy hearty meals like dumplings and tangyuan (glutinous rice balls) to promote unity and harmony.

Generated with DALL·E.

Yalda Night: Celebrated on the Winter Solstice, Yalda Night marks the victory of light over darkness in Iranian culture. Families gather to read poetry and enjoy fruits like pomegranates and watermelons, symbolizing the red hues of dawn and the glow of life.

Generated with DALL·E.

Krampusnacht: Observed on December 5th in Austria and parts of Central Europe, Krampusnacht or "Krampus Night" features the figure of Krampus—a mythical creature who punishes misbehaving children. The festivities include parades and events where participants dress up as Krampus, adding a blend of folklore and excitement to the winter season.

Generated with DALL·E.

Christmas: Celebrated on December 25th, Christmas commemorates the birth of Jesus Christ and incorporates various traditions, including feasting, gift-giving, and the decoration of evergreen trees.

Generated with DALL·E.

These festivities, rooted in the astronomical significance of the Winter Solstice, highlight humanity's enduring connection to the cosmos.

As we embrace the winter season, let the night sky inspire wonder and curiosity, reminding us of our place in the vast universe.

1 Comment