August brings the third of the four star families to the eastern night sky.
Manaiakalani, the Chiefly Fishing Line, comprises the Summer Triangle in the northeast and Maui’s Fishhook, Scorpio, in the southeast. The Summer Triangle represents a coil of fishing line that leads to the southeast and is secured to the top of Maui’s Fishhook. Manaiakalani fishes for Pimoe, Sagittarius, the celestial crevalle (ulua) that swims toward the barb of Maui’s Fishhook.
The Summer Triangle consists of a trio of stars: Keoe, Vega in the constellation Lyra the Harp; Pira‘etea, Deneb in the constellation Cygnus the Swan; and Humu, Altair in the constellation Aquilae the Eagle.
Vega, which rises in the northeast, was our northern pole star in 12,000 B.C. Over time the earth’s axis of rotation gradually shifts in a process called precession of the equinoxes. A precession cycle takes 25,770 years, during which time the earth’s pole travels a circular path across the celestial sphere.
Our current pole star, commonly known as the North Star, is Hokupa‘a, Polaris. In 14,000 A.D., Keoe will once again return to its pole star position.
In the southeast, Kamakaunuiamaui, Maui’s Fishhook, is the constellation Scorpius.
It is not hard to imagine why Polynesians thought that this constellation resembled a fishhook or why Babylonians and Greeks thought that it resembled a scorpion. At the center of Kamakaunuiamaui is Lehuakona, Antares, the heart of the scorpion, a red supergiant irregular variable star. It is the 15th-brightest star in the night sky, and if placed within our solar system, its massive size would stretch between the orbits of Mars and Jupiter.
Hawaiian star lore accounts of the demigod Maui imagine that Maui’s Fishhook is fishing for a magical ulua, Sagittarius, Pimoe. Pimoe is a recognizable asterism; it takes the shape of a celestial teapot, complete with a cover, spout and handle. Within Sagittarius lies our Milky Way galaxy.
In a section of Sagittarius defined as Sagittarius A (SgrA), astronomers have evidence of a supermassive black hole. The Keck Telescope here in Hawaii and the Very Large Telescope in Chile have detected stars orbiting SgrA at velocities greater than other stars. Astronomers utilize the Keck Observatories to study this star at its closest approach to our supermassive black hole; in doing so, astronomers are able to test Einstein’s theory of general relativity.
Special events
A recently discovered comet has been visible in our sky for the past few weeks and has been capturing the attention of stargazers, photographers and astronomers.
Comet C/2020 F3 (NEOWISE), or Neowise for short, was discovered in March as it entered the inner solar system. It made its closest approach to the sun during the first week of July and passed over the earth’s orbit Thursday. It is now on its way back to the outer solar system and won’t return to the inner solar system until the year 8786.
The comet can currently be viewed in the evening sky near the shape of Nahiku, the Big Dipper. For some time it has been visible to the naked eye and can appear to be like a faint wispy cloud near the horizon; as Neowise moves farther away from the sun, however, it will get fainter and fainter.
Skilled observers with binoculars, a telescope or even a good camera zoom will be able to just catch the magnificent tail of this comet.
Every summer, our sky is decorated with the beautiful Perseids meteor shower. This shower will be active from late July through mid-August, with a peak of activity occurring Aug. 12 at about 3 a.m.
The shooting stars in this meteor shower are the remnants of material left from the comet Swift-Tuttle; when this comet last passed through the inner solar system in 1992, it left behind a cloud of dust and ice in Earth’s orbit.
Every year when the earth passes through this debris cloud, the dust and ice fall through our atmosphere and burn up, creating the shooting stars of the Perseids meteor shower.
At its peak we can expect 60-150 shooting stars per hour. The shooting stars will mostly travel across the sky from east to west, roughly originating from the constellation of Perseus, which will rise in the east.
Morning observations
Morning observers with a careful eye will be able to watch a parade of planets as they await the rising sun.
In early August starting at 4 a.m., observers will be able to see the bright planet Jupiter preparing to set in Manu Kona, closely followed by the fainter planet Saturn. These two planets have been our companions throughout the evening.
As time goes on the distinctive red planet, Mars, will be high in the center of the southern sky just before 5 a.m. As dawn starts to color our sky, between 5 and 5:30 a.m., the extremely bright planet Venus will rise out of Manu Ko‘olau, followed by the fainter planet Mercury, which will stay close to the horizon. In these early morning hours Venus will stand out; it is the third-brightest object in the sky after the sun and the full moon.
Together, the aforementioned five planets — Mercury, Venus, Mars, Jupiter and Saturn — along with the sun and the moon form what archeo-astronomers term as seven luminaries. Tracking the location of these objects was an early focus of astronomical sciences and was a key component in the lives of people who lived long ago. The seven luminaries played a part in how we organize time, the names of our seven days of the week.
August 2020 Sky Chart by Honolulu Star-Advertiser on Scribd
Chad Kalepa Baybayan (Kalepa.Baybayan@hawaii.edu) serves as navigator-in-residence and Emily Peavy (Emily.Peavy@hawaii.edu) as planetarium technician support facilitator at the ‘Imiloa Astronomy Center of Hawaii, a center for informal science education at the University of Hawaii at Hilo showcasing astronomy and Hawaiian culture as parallel journeys of human exploration.
