Bright stars, bright Mars and a vanishing Moon will highlight the winter sky over Washington. Our longest nights are replete with celestial sights to delight anyone who enjoys crisp cold evening walks under the season's colorful constellations.
The reason for the season: The solstice
The winter solstice occurs early on Dec. 21 at 4:21 a.m. Eastern time. This is when the sun reaches its most southerly point in the sky for the year, yielding the year's longest nights.
In Washington, we will have 14 hours and 33 minutes between sunset and the following sunrise for several days before and after the 21st. Washington's latest sunrise, however, won't occur until early next year, on Jan. 4 -- in part a result of Earth's elliptical orbit around the sun and our need to keep uniform time.
That same Jan. 4 date is when Earth reaches perihelion, its closest point to the sun for the year. This will occur at 8:28 a.m. Eastern time, when the distance from our daytime star will be a mere 91,406,000 miles.
The moon through the season
There will be three full moons between the winter solstice and the vernal equinox. These will occur on Jan. 13, Feb. 12 and March 14.
The latter one will be notable, as the moon will be totally eclipsed by the shadow of the Earth. The good news is that it will be visible from the entire country, including Alaska and Hawaii. The bad news is that it will be an early-morning event for those of us on the East Coast.
The moon will enter Earth's umbral shadow at 1:09 a.m. Eastern time on that date, and totality will begin at 2:25 a.m. Mid-eclipse will occur at 2:59 a.m., with totality ending at 3:32 a.m. The moon will leave the umbral shadow at 4:48 a.m.
The last total lunar eclipse visible from Washington was on May 16, 2022, and the next one won't occur until June 26, 2029. Moon watchers will get a bonus event on the evening of Jan. 9, when the moon conceals many stars in the famous Pleiades star cluster between 8 p.m. to 11 p.m. Eastern time.
Planets light up the skies
The winter sky will be graced with the five bright planets visible to the naked eye, but three of them will desert us by the equinox.
Sky watchers have probably already noticed Venus, which is visible in the southwestern sky shortly after sunset. The planet's dazzling glow is hard to miss, and it will remain a fixture in this part of the sky until March, when it begins a precipitous drop toward the horizon. During early January, Venus will move closer to the more subdued yellow glow of Saturn, and the two objects will be about two degrees apart on the evening of Jan. 18. Saturn will lag behind Venus before disappearing into evening twilight in late February.
As Saturn fades, the elusive planet Mercury will move into the evening sky for a brief appearance during early March. The best opportunity to spot Mercury will be between March 7 and 14, when the planet will be about six degrees to the left of Venus in deep twilight. Find a good viewing site with a flat western horizon and use binoculars to try to spot Mercury. Both Venus and Mercury will then drop like stones from the sky, vanishing behind the Sun by March 23.
Mighty Jupiter dominates the overnight hours throughout the winter months. Viewers will find its cheery glow among the stars of Taurus throughout this period. Jupiter is a treat for telescopic viewing. Almost any telescope will reveal its four large moons, and each increase in telescope aperture will reveal more details on the planet's striped disc.
A good five- or six-inch telescope should also reveal the planet's famous great red spot, a storm in the planet's atmosphere that's as large as Earth.
The last planet to join the parade is ruddy Mars, which reaches opposition from the Sun on Jan. 15. During the course of the winter months, it will move westward toward the stars Castor and Pollux in Gemini, then reverse course in mid-February, passing the twin stars in early April. Its red glimmer will gradually fade as it moves eastward along the zodiac, and it will linger in the sky until late summer.
The brightest stars for the longest nights
For me, the dazzling constellations that surround the well-known figure of Orion are the highlight of the winter sky.
Nine of the 25 brightest stars in the sky are in the same field of view as the Hunter, including the brightest of all, Sirius.
We can trace a large pattern made up of many of these stars by moving our gaze clockwise from Sirius's icy blue glow past the stars Procyon, Pollux, Castor, Capella, Aldebaran and back to Rigel, the bright blue star that marks one of Orion's "knees."
Scattered throughout these constellations are dozens of bright star clusters and the softly glowing light of the Great Orion Nebula, which can be seen with the naked eye as the small fuzzy patch of light in the "sword" that hangs below Orion's three "Belt Stars."
The nebula is one of the most striking objects to view in an amateur telescope, with swirling clouds of glowing gas that are actively forming new stars. It's well worth some frozen toes to take in this wonder of the deep cosmos.