March Equinox: Welcoming Spring and Celestial Sightings in the D.C. Area
As the winter months come to an end, we eagerly anticipate the arrival of spring. March brings with it longer days and a shift in the celestial landscape, making it an exciting time for sky watchers. One of the most significant astronomical events of the month is the vernal equinox, which marks the official beginning of spring. This year, the equinox falls on March 19 at 11:06 p.m. Eastern time.
The vernal equinox occurs when the center of the sun’s disk crosses the celestial equator into the sky’s northern hemisphere. In ancient times, this event marked the beginning of a new year in many cultures and continues to hold religious significance in various traditions. The point in the sky that defines the equinox is often referred to as the “first point of Aries,” a term still used in astrology. However, due to a phenomenon called the “precession of the equinoxes,” the equinox now lies in the constellation of Pisces, rather than Aries.
The term “equinox” signifies the concept of “equal night,” when day and night are approximately 12 hours in duration. In reality, the sun rises slightly above the horizon a few days before the equinox. In Washington D.C., the date for 12 hours of daylight and darkness this year is March 16, with sunrise at 7:17 a.m. Eastern time and sunset at 7:17 p.m.
In addition to the equinox, there are other celestial events to look out for in March. Early in the month, on March 3, early risers can catch a glimpse of the last quarter moon before dawn in the southern part of the sky. Less than a degree away from the moon is Antares, a bright red-tinted star that serves as the heart of Scorpius, the Scorpion.
The new moon falls on March 10, and throughout the month, the moon will wax in the evening sky, reaching its full phase on March 25. The March full moon is traditionally known as the Worm Moon, as it signifies the time when the ground becomes soft enough for earthworms to emerge, providing a food source for birds and animals. It is also referred to as the Crow Moon and Sap Moon in different cultural traditions.
March also brings the start of daylight saving time in most parts of the United States. On March 10, clocks will be set ahead by one hour before going to bed on Saturday night. This annual time change is governed by congressional authority through the Transportation Department, and while it may cause confusion for some, it remains a part of our yearly routine.
When it comes to stargazing, March offers a transition from the winter constellations to a new set of stars. By mid-evening, the familiar winter constellations can be found in the western sky, but they will gradually set earlier as the month progresses. Orion, with its bright stellar companions, will be visible for the last time until late autumn.
One constellation that remains prominent throughout the year is the Big Dipper, which can be seen in the western sky. The seven stars that form this pattern are part of the larger constellation Ursa Major, the Great Bear. The two stars at the end of the Dipper’s “bowl” point towards Polaris, the North Star.
Following the “pointers” of the Big Dipper towards the south, stargazers can spot Leo, the Lion. Leo consists of two distinct star groups, with Regulus being its brightest star. To the east of Regulus lies a right triangle of stars that mark Leo’s hindquarters.
If you follow the arc made by the Big Dipper’s “handle,” you will come across Arcturus, the signature star of spring. As the brightest star in the northern sky and the fourth brightest overall, Arcturus stands out with its rosy tint, reminiscent of the colorful blooms that will soon adorn the landscape.
While March may not offer many bright planets for observation, Jupiter dominates the western sky during the evening hours. After sunset, Jupiter can be easily spotted until it sets around 11 p.m. or 10:30 p.m. In the early morning hours, Venus may be visible in the southeastern sky, although it will be low on the horizon.
Toward the end of the month, there is a chance to catch a glimpse of Mercury, the most elusive of the planets. Look for Mercury about 30 to 45 minutes after sunset from March 17 to March 31, when it will be approximately 10 degrees above the western horizon. Binoculars can aid in locating Mercury in the twilight glow, after which it should be visible to the naked eye.
For those in the D.C. area interested in observing celestial phenomena, there are several opportunities throughout March. The George Mason University Observatory