~ St. Maarten’s Backyard Astronomy for June 22 & 23 ~
Sun rises at 5:37am
Sun sets at 6:50pm
Moon phase: third quarter, waning gibbous
Moon sets: 10:03am, Saturday
Moon rises: 11:04pm, Saturday
This weekend, we celebrate the Summer Solstice – the northern hemisphere’s longest day and shortest night. June 21 or 22, each year, is the day that brings these natural extremes of daylight and darkness. The Northern Hemisphere has its time of greatest daylight; meanwhile, the southern hemisphere has its shortest day and longest night of the year. Here in the Northern Hemisphere, noontime shadows are shortest on the summer solstice. Sometimes, we call it the first day of summer, but the June Solstice is also known as Midsömer in the Scandinavian countries. Whether you consider this weekend the start of summer or the middle of summer, it’s worth appreciating the significance of this special point in the yearly calendar.
Our planet’s tilt as it orbits around the sun is what gives us the solstice as well as our seasons. Although modern science understands the geometry of the solar system that is responsible for the solstice, ancient people have always been acutely aware of this annual pivot point. They observed the skies, the arc of the sun across the dome of heaven, its shifting cycles and they could predict those cycles with high accuracy. They built monuments to them, at Stonehenge in England and Chaco Canyon in North America and thousands of other historical sites.
Interestingly, if you live north of the Arctic Circle, this is the day in which the sun neither rises nor sets. It stays above the horizon for 24 hours around the clock. South of the Antarctic circle, the sun neither rises nor sets, but stays beneath the horizon for 24 hours.
Each solstice marks a “turning” of the year. To many cultures, the solstice can mean a limit or a culmination of something. From around the world, the sun is now setting and rising as far north as it ever does. After the June solstice, the sun begins its subtle shift southward on the sky’s dome again.
In other celestial considerations, look up in the night sky to find the Summer Triangle. This asterism is made of the brightest stars from three constellations: Cygnus the swan, Lyra the harp and Aquila the eagle. If the sky is clear and dark, you may even detect the Milky Way passing through the triangle.
Also the planet Mercury reaches a milestone in the evening sky, making it easier for star gazing fans to find. Mercury is often lost in the sun’s glare. But right now, Mercury now stays out more than an hour after the sun. To spot Mercury, find an unobstructed horizon in the direction of sunset. Then, starting an hour or so after sundown, watch for Mercury to pop out rather low in the western sky and near the sunset point on the horizon.
Thank you for keeping up with the Night Sky articles. If you are out later on in the week, each star rises about four minutes earlier each day than written here, and the moon rises 50 minutes later. Night Sky is researched and compiled by Lisa Davis-Burnett. Earthsky.org is a key resource for information and images. Questions or comments? Email firstname.lastname@example.org