From the completion of the epic voyage of the Hokule‘a to the naming of an asteroid detected from Hawaii, and the latest findings of gravitational waves in space, 2017 has been an exciting year for astronomical explorations on Earth and in space.

In June the Malama Honua voyage of the Hokule‘a ended with the canoe’s return to Hawaiian waters, bringing to a close the closely monitored three-year international trip. On its voyage, with the crew navigating by the stars and taking other clues from nature, Hokule‘a sailed 44,000 nautical miles, stopped at over 150 ports, visited 19 countries and enlisted about 250 crew members.

‘Oumuamua, meaning scout or leader, is the first observed asteroid to visit Earth from interstellar space. Its brief visit to our solar system was discovered only 10 weeks ago by University of Hawaii researcher Rob Weryk, using the university’s Pan-STARRS telescope on the summit of Haleakala. This asteroid, the length of about seven football fields, is now on a path that is taking it rapidly away from Earth and the sun to continue its journey into deep space. According to researchers, the asteroid could be rocky with a surface that possesses a high metal content.

Gravitational waves, ripples in space predicted by Einstein in his theory of relativity, were first observed by astronomers and physicists in 2015. Researchers have since detected other gravitational waves and have assumed that the collision of black holes produces the strongest waves. However, on Aug. 17, a historic discovery was made of gravitational waves emitted from a kilonova, a neutron star merger, an event that had been theorized but never observed. Astronomers can now use this gravitational wave detection to locate light emitted from the collision. This discovery marks a whole new way for astronomers to observe the universe.

Navigating the night sky

The circle of the horizon gives physical shape to the Hawaiian Star Compass. To make the compass functional, the navigator memorizes the rising and setting points of key stars. To organize the night sky, the celestial sphere is divided into four sections, identified with specific “starlines.” A recent creation of the voyaging community, the four starlines follow traditional Hawaiian themes and are used as a heuristic, or hands-on, technique to learn and acquire navigational skills.

Starlines are a collection of bright stars and constellations that line up north to south.

The four starlines are Kekaomakali‘i (the Bailer of Makali‘i), Kaiwikuamo‘o (the Backbone), Manaiakalani (the Heavenly Fishing Line) and Kalupeakawelo (the Kite of Kawelo). Because each is most prominent in the night sky at a particular time of year, they also serve as seasonal starlines for winter, spring, summer and fall.

The winter starline, Kekaomakali‘i, is in the shape of a canoe bailer, scooping up the stars on the eastern horizon and emptying them out in the west during its nightly transit across the sky. The scoop part of the bailer is made up of the northernmost bright star Hokulei, or Capella, in the constellation Auriga. Hokulei rises in the star house Manu Ko‘olau. The bailer arcs toward the eastern horizon and the constellation Namahoe (the Twins), or Gemini, and the two bright stars Nanamua (Looking Forward), or Castor; and Nanahope (Looking Back), or Pollux.

The starline turns south toward the constellation Puana (Little Dog), or Procyon, and continues southward to the brightest star in the night sky, ‘A‘a (Burning Brightly), or Sirius. The handle of the bailer is made up of ‘A‘a and the second brightest star in the night sky, Keali‘ikonaikalewa or Canopus.

The scoop of the bailer is filled with constellations. Closest to ‘A‘a is Kaheiheionakeiki (Cat’s Cradle), or Orion’s Belt, a string game played on the fingers of children. The northernmost star of the three that forms the belt, Mintaka, marks the eastern star house, Hikina. Moving northwest and through Orion’s Belt will lead you to Kapuahi (Sacred Fire), or Aldebaran, the eye of Taurus the Bull. Continuing along the northwest is the fuzzy constellation Makali‘i, or Pleiades, in the eastern evening sky, which also marks the beginning of the Makahiki season, when the Hawaiian chiefly class collected tribute and the commoner class celebrated with athletic competitions.

Thus, the four starlines are used as contemporary tools for learning and organizing the night sky in the context of Hawaiian culture.

January’s night sky

The night sky of 2018 starts off with a supermoon Monday. As mentioned in last month’s column, the moon orbits the Earth in an oval path, which means its distance from Earth changes. When the moon is closest to Earth, that special location on the moon’s orbit is known as perigee. A supermoon occurs when the moon is full and lines up with the perigee.

As the starline of Kekaomakali‘i rises in the east, the starline of Kalupeakawelo will be setting in the west. Just to the east of Kalupea­kawelo, beneath ‘Iwakeli‘i, will be the faint but beautiful Andromeda galaxy.

There will be two full moons in January, one on the first day of the month and one on the last. When this happens, the second full moon is often referred to as a blue moon, even though the moon’s color remains the same. On Jan. 31, the blue moon also will coincide with the moon’s perigee, giving January its second supermoon. To top it off, between 3 and 5 a.m. in Hawaii, the moon will pass through the Earth’s shadow in a lunar eclipse, often referred to as a “blood moon.” On Jan. 31, look forward to viewing a “super blue blood moon.”

In January, sunrise occurs near 7 a.m., giving early risers a beautiful view of the sky with the Nahiku (Big Dipper) in the northeast. On Saturday, Mars and Jupiter will come together and the planets will appear to be almost on top of each other. The best viewing time is 5 a.m.

Chad Kalepa Baybayan (Kalepa.Baybayan@hawaii.edu) is navigator-in-residence and Emily Peavy (Emily.Peavy@hawaii.edu) is planetarium technician support facilitator at the ‘Imiloa Astronomy Center of Hawai‘i (imiloahawaii.org), a center for informal science education on the UH-Hilo campus, showcasing astronomy and Hawaiian culture as parallel journeys of human exploration.