Featured Mauna Kea discovery/observation

Have you ever noticed that the planets Uranus and Neptune are two distinct shades of blue? The two gas giants are composed of many of the same materials and are essentially twins in their composition; however, their atmospheres are different colors. Why might that be?

Earlier this year, astronomers using the Gemini North Observatory, the NASA Infrared Telescope Facility and the Hubble Space Telescope tackled this question and determined that a layer of concentrated haze of aerosols that exists on both planets is much thicker on Uranus. This observation not only helps explain the differing colors but also gives astronomers insight into the planets’ deeper atmospheres, which assists with the study of new gaseous exoplanets.

“The Gemini observatories continue to deliver new insights into the nature of our planetary neighbors,” said Martin Still, Gemini program officer at the National Science Foundation. “In this experiment, Gemini North provided a component within a suite of ground- and space-based facilities critical to the detection and characterization of atmospheric hazes.”

To learn more about this research visit the press release here: gemini.edu/pr/gemini-north-telescope-helps-explain-why-uranus-and-neptune-are-different-colors

Special events

From mid- to late October, the night skies will be decorated with the Orionid meteor shower. This meteor shower will produce about 20 shooting stars an hour when it peaks on Oct. 21. The shooting stars from the Orionid meteor shower are left from the tail of Halley’s Comet, which came through the inner solar system in 1986.

Evening observations

In the early evening, stargazers will be able to find two of the navigational star families, established by the Polynesian Voyaging Society; these “super constellations” are important tools that are utilized by voyaging canoes Hokule‘a and Hikianalia.

Setting in the west will be the “summer” star family of Manaiakalani. This starline is made up of three main pieces: the Navigator’s Triangle, Pimoe (an ulua fish) and Kamakaunuiamaui, the fishhook of Maui.

Rising in the east will be Kalupeakawelo, also known as “the Kite of Kawelo.” At the center of this starline is the famous “Great Square of Pegasus,” which represents the body of a kite as it is being flown high overhead.

North of the Great Square is the “W” shape of ‘Iwakeli‘i (the royal frigate bird) and the houselike shape of Kamo‘i. The starline also connects to some of the brightest stars in the southern fall sky.

According to legend, Kawelo was a Kauai chief and hero of the Hawaiian people, most notable for the many athletic competitions in which he excelled. In a kite-flying contest with his cousin, Kauahoa, Kawelo twisted, turned and made his kite leap, resulting in both becoming entangled; Kawelo’s kite severs the string of his cousin’s and carries it away in the wind.

Kawelo fears he will be punished by his much larger cousin, but Kauahoa blames the wind. Those watching the competition interpret the incident as a sign of Kawelo’s supernatural power.

Kalupeakawelo, the kite of Kawelo, is set up to take a sort of 3D effect in the sky. To properly picture the kite in the sky, imagine that you are lying back and holding the strings that attach to ‘Iwakeli‘i and Kamo‘i with one hand, and holding the strings that attach to Nalani and Kaikilani with the other hand. The square body of the kite, marked by Manokalanipo, Kakuhihewa, Pi‘ilani and Keawe, flies high up above your head.

Hidden within Kalupea­kawelo is the closest galaxy to the Milky Way, the Andromeda Galaxy. While the Andromeda Galaxy is visible to the naked eye, it can often be a bit difficult to observe.

In order to view it, observers should ensure that they have a clear dark night sky with little to no light pollution. In the northwestern sky, first find the notable constellation of ‘Iwakeli‘i and look about 15 degrees south of the constellation’s “elbow,” where you will find a faint fuzzy blur in the night sky — this is the Andromeda Galaxy. The Andromeda Galaxy is our closest galactic neighbor and contains approximately 1 trillion stars, much more than the estimated 250 billion stars in the Milky Way. As the largest galaxies in our local galactic cluster, the Andromeda and Milky Way galaxies are caught in each other’s gravities and are set to collide about 4.5 billion years from now.

The gas giant planets Jupiter and Saturn will stand out amid the southern kite strings of Kalupeakawelo. Saturn will be the fainter of the two but will still be visible because planets do not usually twinkle in the sky. Through a telescope, observers can see the beautiful rings of Saturn which make the planet famous. While every gas giant in our solar system (Jupiter, Saturn, Uranus and Neptune) has a system of rings, Saturn’s rings are by far the most noticeable as they are much larger and composed largely of ice which makes the rings more reflective and noticeable.

Jupiter sits to the east of Saturn; as the fourth- brightest object humans can see in the sky, Jupiter will stand out along the western horizon. By using a pair of binoculars or a telescope, observers will notice four bright dots that accompany the gas giant planet. These are Jupiter’s four largest moons; Io, Europa, Ganymede and Callisto. These four moons are often referred to as the “Galilean moons” as they were first recorded by Galileo Galilei in 1610.

Morning observations

Throughout October, sunrise takes place just before 6:30 a.m., meaning the sky will still be dark enough for stargazing until just after 5:30.

Early-morning stargazers will see a very different perspective of the sky. High in the sky around 5 a.m., observers will be able to find the famous shape of Orion, or Kaheiheionakeiki — the hei game (cat’s cradle) of the child.

Just north of Kaheiheionakeiki, the distinctive planet Mars will appear very close to the center of the sky. Mars will be sitting close to two bright red giant stars, Aldebaran and Betelgeuse, creating a triangle of three bright red astronomical objects.

Northwest of Kaheiheio­nakeiki, we will also see the famous star cluster of Makali‘i, also known as the Pleiades, or the Seven Sisters. And toward Manu Malanai, ‘A‘a, also known as Sirius, will be highly noticeable in the sky as the sun rises. ‘A‘a is the brightest star that can be seen in the twilight sky.

October 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.