Galactic arms embrace August’s rare night skies
Skywatching August’s night skies is one of those rare activities that can truly pull one out of oneself by its ability to inspire enlightenment, profound realizations and the thrill that comes with the knowledge of one’s existential and eternal connection to the universe.
The easiest way for the skywatcher to start on the path to understanding the fundamentals of universal interbeing is by simply looking straight up at zenith around 9 p.m. any August night beneath clear, dark skies. Here, the Milky Way galaxy stretches from below the northeast horizon and directly overhead before plunging beneath the southern skyline. From constellations Perseus to Sagittarius, the galaxy embraces the sky with immense arms of star clouds and suns in the billions.
For the ultimate skywatching experiences, consider spending a few nights in some of Colorado’s best dark sky refuges. Visit colorado.com/ articles/15-places-stargazecolorado for ideas. Note: attempting to skywatch at a Red Rocks, Morrison concert is not recommended by this reporter.
The Milky Way is the primal source, the cradle of all that is and ever has been of the Earth and solar system. The current thinking is that the shockwave of a supernova impacted dense, filamentous clouds of molecular hydrogen, causing them to collapse to form the sun, planets, etc.
The process of star birth is still going on, and you can see it for yourself. Train a telescope due south onto teapot-shaped Constellation Sagittarius, the hippocentaur archer, which reaches its highest point in the sky for the year (culminates) at 9 p.m. Aug. 20. Located a few degrees west of the teapot’s knop — between the Lagoon Nebula (M8) and globular cluster M28 — you’ll find emission and reflective nebula NGC 6559 in the act of showering the interstellar medium with thousands of beautiful, hot new stars.
Due to its location near the intersection of three main galactic arms near the Galactic Center, Sagittarius, along with Scorpius, is one of the densest and therefore most fascinating regions of the sky. The Sagittarius Star Cloud, the barred galaxy’s brightest region, is part of its central bulge and easily recognizable by its dark Great Rift. Make time to revel here in the diverse nebulae, globular star clusters and sheer outpouring of stars. There are a few small galaxies within the bounds of the constellation, but they’re dim, distant fuzzes and perpetually below the horizon for skywatchers at 40 degrees north.
Sagittarius is extraordinarily rich in celestial marvels, but the downside is that it’s close to/ beneath the horizon and sometimes subject poor seeing due to perturbations in the atmosphere’s layers.
This is not the case with mid-latitude Constellation Aquila, the eagle, on the celestial equator bathed in the background star clouds of the Milky Way. Culminating on the north/south meridian at 9 p.m. Aug. 30, the eagle is excellently positioned for star gazing with binoculars and small telescopes. Although it is home to planetary nebula and globular clusters (both so-called because of their apparent orb-shapes in early telescopes), Aquila is impressive primarily for the beauty of the asterism’s components themselves.
A random selection of the stars of Aquila proves the point. 15 Aquilae, an optical double of an orange-hued giant with a purple-hued secondary, is easily separated in amateur scopes. R Aquilae, a red giant 400 times the diameter of the sun, varies in brightness by about magnitude 2.5 over the course of its long pulsations. Eta Aquilae and FF Aquilae are both variable yellow- white supergiants that oscillate between their minimum/maximum brightness, diameters and temperatures is less than a week.
Constellation Lyra, the kithara of Orpheus, is a small yet impressive constellation. Culminating at 9 p.m. Aug. 15, Lyra’s brilliant alpha star Vega is only a few degrees east of zenith, making it a superlative target for any and all forms of celestial adventuring including astrophotography. A moderate telescope will reveal the famed planetary Ring Nebula, a star sloughing off its outer layers of gas before slowly “dying” as a cooling, non-fusing stellar core known as a white dwarf.
Vega, which was seen as a falling eagle/vulture by ancient Arabs, Romans, Egyptians and Indians, is interesting in and of itself for several reasons. Vultur Cadens is the fifth brightest star in the night sky, and together with avian constellations Altair of Aquila and Deneb of Cygnus, the swan, forms the Summer Triangle. The vulture was the northern pole star about 12,000 BCE, and, due to precession of the Earth’s rotational axis, will be the North Star once again beginning around the year 13,727.
The Summer Triangle has been recognized only as such since 1913, and was called the Navigator’s Triangle by mid-20th century USAF navigators. The same three stars, however, have been part of a classic Chinese folk tale, “The Weaver Girl and the Cowherd,” for at least 2,600 years.
This skywatcher’s guide would be remiss in its duty if it were to neglect the most important advancement in astronomy since Galileo’s breakthroughs of modern science and observational astronomy. As the golden age of astronomy gets thrown into high gear with the deployment of the James Webb Space Telescope (JWST), astronomers and skywatchers now have the most powerful space telescope in history to study the universe, its primordial hydrogen reionization and the earliest galaxies in their infancy.
The Perseid meteor shower peaks overnight Aug. 11-12. The full moon will wash out all but the brightest meteors until the pre-dawn hours. The moon is full at 7:35 p.m. Aug. 11, and is called the Full Sturgeon Moon.