The four stars that form the corners of Ka Lupe a Kawelo, the Great Square of Pegasus, are excellent pointer stars that show the direction of both the north and south celestial poles, and serve as an indicator of the path they take across the night sky as they move from the eastern to the western horizon.
The first two stars that appear in the east are Kakuhihewa (Scheat), rising on the boundary of the compass house Noio-‘Aina Ko‘olau, and Keawe (Markab), rising on the boundary of ‘Aina-La Ko‘olau. Because they rise at about the same time, they will cross the celestial meridian together, making them a meridian pointer.
Meridian pointers are any two stars that cross the celestial meridian together, and in the tropics they help indicate the celestial north and south poles.
The second pair of stars in Ka Lupe a Kawelo to arrive in the east are Manokalanipo (Alpheratz) and Pi‘ilani (Algenib); they rise and set along the same boundaries of Noio-‘Aina Ko‘olau and ‘Aina-La Ko‘olau.
These two sets of pointer stars point toward the north celestial pole.
To find the south celestial pole, draw a line through Kakuhihewa (Scheat) and Keawe (Markab); continue the line southward and through Kukaniloko (Fomalhaut) for one set of southern meridian pointers. For the second set of pointers, draw a line through Manokalanipo (Alpheratz) and Pi‘ilani (Algenib), then through Kaikilani (Ankaa).
Because Kakuhihewa, Manokalanipo, Keawe and Pi‘ilani rise and set in the same compass house, they will always point out the direction to those compass houses on the horizon. Within the tropics you can draw a line between these stars and calculate the angular path these stars take on their nightly east-to-west trek.
Featured Mauna Kea discovery/observation
Just north of the bright red giant star Kapuahi and to the east of the Makali‘i star cluster, astronomers are studying the faint stellar nursery of the Taurus molecular cloud.
In this endeavor, astronomers worked with the Subaru Telescope and the W.M. Keck Observatory to discover the youngest planet ever found orbiting a distant infant star. While thousands of planets have been discovered orbiting distant stars, this small planet is unique as it has only recently formed around its star and innovative researchers have been able to directly observe it.
The continued research on the planet will help humanity unlock secrets of our own origins as we better understand the process in which planets form around young stars.
Special events
The Geminid meteor shower, considered by many to be the best meteor shower of the year, runs through the first couple of weeks of December, peaking at 8:25 a.m. Dec. 13. While this is the best time to view the shower, there will be a multitude of shooting stars in the surrounding days.
At its height, this shower will typically produce up to 120 shooting stars an hour.
The Geminid meteor shower is somewhat peculiar because the meteors do not originate from a comet, but from the asteroid 3200 Phaethon, whose orbit passes close to Earth’s orbit every 1.433 years. In 2017 this asteroid had a relatively near-Earth approach (about 6.2 million miles, or 27 lunar distances from Earth), which allowed astronomers to study the asteroid in great detail.
The winter solstice for the Northern Hemisphere takes place Dec. 21; the sun will rise and set at its southernmost position in the sky. The sun will travel at its lowest arc across the sky, marking the shortest day and longest night of the year.
In Honolulu the sun will rise at 7:04 a.m. and set at 5:54 p.m., yielding just 10 hours and 50 minutes of daylight. The days will get shorter and the nights longer until Dec. 21; then the days will gradually get longer again.
Evening observations
As we are in the winter season, the sun sets fairly early in the evening. Throughout most of December the sun will set between 5:48 and 6 p.m., with dusk fading from the evening sky as early as 7:05 to 7:19 p.m.
In these early evening hours, from the southwestern horizon we will see three planets in alignment.
As dusk fades from the sky, the first planet to stand out will be the incredibly bright planet Venus, which will set just around 8 p.m.
Above Venus will be a pair of giant gas planets, Saturn and Jupiter. Saturn will appear quite faint in the sky but will still stand out against the background of stars, especially as it will likely not be twinkling.
Planets typically do not twinkle because they are so much closer to Earth than the distant stars. This closeness means that more direct light from the planet will reach us and the atmosphere will not disturb the light in the same way that it disrupts the light of the stars.
Through a pair of binoculars or a good telescope, we will be able to see Jupiter’s four largest moons, and the rings of Saturn will just barely come into focus. We can also observe the different bands of gas in Jupiter’s atmosphere, clearly see the rings of Saturn and begin to see Saturn’s largest moons.
The fall starline of Kalupeakawelo, the Kite of Kawelo, will stretch high over our heads during the early evening hours. In the northern sections of the kite, we can find the “W” shape of ‘Iwakeli‘i, the royal frigate bird.
After finding ‘Iwakeli‘i, we can follow a line from the western “elbow” of the iwa bird down 15 degrees to the south.
Beneath ‘Iwakeli‘i lies a small fuzzy smudge from the light of the Andromeda galaxy, the closest large galaxy to the Milky Way. Andromeda is approximately 2.5 million light-years away, meaning that light from that galaxy has traveled 2.5 million light-years before finally reaching Earth.
As we fully transition into our winter months, a notable arrangement of stars will begin to rise in our early evening sky.
Heiheionakeiki, known as the string game of the child or Orion the Hunter, is a famous formation of stars known around the world. This group of seven stars sits exactly on top of the celestial equator, which divides the sky into the Northern and Southern hemispheres, and it can be seen no matter where you are on the planet.
Moving south of the famous Orion’s Belt, through a good telescope you can see the details of a fuzzy region known as the Orion Nebula, one of the most famous stellar nurseries in the sky. Amongst these giant clouds of gas and dust, material is condensing to create new stars.
Morning observations
Throughout December the sun will rise between 6:52 and 7:08 a.m. The early morning sky will look very different from the evening sky. The rusty red planet Mars will stand out in the eastern sky during these early morning hours with a distinctive reddish color.
In the early morning hours, Hanaiakamalama, the Southern Cross, will return to our island skies. This notable shape of stars will begin to rise in the south east about an hour before the sun rises.
December 2021 Sky Chart by Honolulu Star-Advertiser
The ‘Imiloa Astronomy Center of Hawaii is a center for informal science education at the University of Hawaii at Hilo showcasing astronomy and Hawaiian culture as parallel journeys of human exploration.
