This week finds a relative paucity of bright planets in our evening sky. Only one, Mercury, is available by month's end, but even then, this rocky little world can only be glimpsed for about 30 to 45 minutes after sundown very low to the west-northwest horizon. After that, you'll have to wait until after the witching hour of midnight to sight another celestial wanderer, Saturn.
That having been said, let's turn our attention to two celestial objects that can readily be seen during evening hours this week from even from bright cities. One is our nearest neighbor in space, while the other is a familiar pattern of stars.
The first is of course, the moon, which will turn full on the first full day of summer, June 21. The moment when the moon "officially" turns full will come that evening at 9:08 p.m. Eastern Time; the moon will be above the horizon for most eastern states, though for much of the central and western U.S. it will have yet to have risen. No problem, however, since for a day or two on either side of June 21, the moon will appear practically full for most casual observers.
Native American tribes of a few hundred years ago kept track of the seasons by giving distinctive names to each recurring full moon. Their names were applied to the entire month in which each occurred. According to our Space.com listing of full moon names, the full moon of June was traditionally known to every Algonquin tribe as the "Strawberry Moon," likely because strawberry picking season peaks during this month. Europeans called it the Rose Moon.
Want to capture photos of tonight's full moon? Make sure to see our guide on how to photograph the moon. If you need imaging gear, consider our best cameras for astrophotography and best lenses for astrophotography to make sure you're ready for the next eclipse.
And if you're looking for some new binoculars or a telescope to observe the moon, check out our guides for the best binoculars and best telescopes.
Related: June full moon 2024: The Strawberry Moon follows the solstice
Another June lunar moniker
Looking for a telescope to see the full moon up close? We recommend the Celestron Astro Fi 102 as the top pick in our best beginner's telescope guide.
Based solely on astronomical geometry, British astronomy popularist Guy Ottewell in his annual Astronomical Calendar, sometimes has referred to the June full moon as the "Honey Moon." The sun in June is at its greatest distance to the north of the celestial equator and the full moon (which is nearly opposite to the sun in the sky) is therefore at its greatest distance to the south of the celestial equator. The full moon of June is therefore seen especially low in the southern sky. Objects seen low in the sky are affected by the reddening properties of the atmosphere.
Consequently, the full moon in June usually has a beautiful golden appearance, just like good honey.
There are many other effects of atmospheric reddening. The most obvious is the rising or setting sun. When the sunlight passes through a great thickness of the atmosphere, most of the blue light is absorbed and scattered away; the red light comes through preferentially. The reddening of stars when they are seen close to the horizon is less obvious to the casual observer. Finally, the red color of the moon during a total lunar eclipse is due to sunlight being reddened as it passes through the Earth's atmosphere and then bent by refraction into the Earth's shadow.
Big Bear or Dipper?
During this week, as the sky darkens sufficiently to allow us to see stars, we can look well up into the northwest sky and catch sight of the seven stars that form the Big Dipper. At this time of the year, the Dipper is oriented sideways, with the bowl pointed downward and the handle straight up.
Interestingly, scholars are fairly sure that the oldest of our star groups trace back to the Mesopotamian peoples of five or more millennia ago. In fact, the creatures that were made into the ancient Western constellations are similar to those in the Bible. And there are hints that some are far older. The fact that the seven stars of the Big Dipper formed a bear to Native Americans and to the cultures of the Old World and Siberia suggests that our Ursa Major is a piece of Stone Age culture at least 8,000 to 12,000 years old. That is the estimated era of the last migration from Siberia to North America across the Bering Strait.
And yet strangely enough, the Big Dipper itself has been a source of frustration to some constellation historians: Just who originated this name?
In Great Britain, it is better known as the Plough. But as a Dipper it is strictly an American phenomenon; this celestial "drinking gourd" was often mentioned in mid-19th-century books, but not before then. It's unfortunate that the Little Dipper is so much fainter and more difficult to see compared to the Big Dipper, since — at least to my eyes — it resembles more closely a real dipper, such as might be used to ladle soup. The Big Dipper looks more like a saucepan.
Wagon in the sky
For much of the world this pattern has been, if not a bear, then some sort of a wagon, chariot or other wheeled vehicle. In Shakespeare's King Henry IV, there is a reference to the Big Dipper as Charles' Wain (a wain being defined as a large open farm wagon). Here is how it is translated from an astronomical passage in Homer's Iliad:
Therein he wrought the Earth and the
heavens, and the Sea.
The unwearied Sun and the full Moon,
And all of the constellations with which the
Heavens are crowned.
The Pleiades, the Hyades, the strength
of Orion
And the Bear, which they also call the Wain.
Which there revolves and watches Orion,
But is alone unwashed by Ocean's briny bath.
These words date back to around 700 B.C., so we can see just how ancient this seven-star asterism is as a wagon.
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications.
