Spring provides the mariner with excellent conditions for tropical passages between the northern and southern hemispheres.

Spring sailing allows the navigator to avoid the Northern Hemisphere’s hurricane season. Tropical springtime winds, moreover, tend to blow from the east under typically deep blue skies. The wind pushes against the surface of the sea, creating a readable swell.

And finally, the night sky in spring is filled with excellent wayfinding clues, with the star family Kaiwikuamo‘o filling the eastern horizon.

Canoe voyage

This year, spring also marks a special time for Hawaii island with the iconic voyaging canoe Hokule‘a spending seven weeks on the island as part of the Polynesian Voyaging Society’s Mahalo Hawai‘i Sail. This statewide sail was launched in August to visit 40 ports around Hawaii to thank local communities for their support of the recently completed Malama Honua Worldwide Voyage (2013-2017), during which Hokule‘a sailed around the world, navigating with the aid of the stars and other natural clues.

A related goal of the Mahalo sail is to reach schoolchildren and share knowledge of traditional wayfinding and teach lessons about conservation efforts around the world.

After visits to ports on Oahu, Kauai, Maui and Molokai in the fall and winter, Hokule‘a arrived in Kona at the end of March, then spent four weeks docked in Hilo, offering canoe tours to local school groups and community members, before departing on Friday for the South Kona community of Milolii. Hokule‘a spent a quiet evening of sharing and storytelling on Saturday, reacquainting the crew and canoe with a population that shares a special bond with Hokule‘a.

In 1985, at the outset of a three-year Voyage of Rediscovery sail to Aotearoa (New Zealand), unfavorable weather forced a one-month delay, during which Hokule‘a remained docked at Milolii, waiting for favorable winds to prevail and developing a close relationship with the community.

Today, Hokule‘a was to make its final Hawaii island stop at the port of Kawaihae, where it will remain until May 10 before sailing back to Maunalua Bay on Oahu. Over 20,000 community members and students have visited Hokule‘a during its stops on Hawaii island.

Highlights of activities include free public wa‘a (canoe) tours and education expos in Kona and Hilo, and a final community day scheduled for 9 a.m. to 2 p.m. May 5 at Kawaihae Harbor.

Evening observing

May’s early evening sky will be full of bright objects. First to set in the west during the early evening will be the incredibly bright planet Venus, the third brightest object in the sky (after the sun and full moon), because of its highly reflective thick atmosphere. As it orbits closer to the sun, Venus will always be seen relatively close to the sun in our sky, rising just before the sun rises and setting just after the sun sets.

As Venus sets in the west, the sky’s fourth brightest object, Jupiter, will rise in the southeast. This planet will be at its brightest on May 8 when it is in opposition — on the opposite side of Earth from the sun.

Jupiter will rise at the same time as the sun sets and will be visible all night. When a planet is at opposition it is at its closest physical position to Earth and looks a bit brighter in the sky. NASA’s Juno Spacecraft is currently orbiting Jupiter and carefully studying the gas giant. To learn more about Juno and download beautiful images captured by the spacecraft, visit the missionjuno.swri.edu website.

The star ‘A‘a, Sirius, the fifth brightest object in the sky, will be setting in May in the southwest. This hot star takes on a bright white-blue color in the evening sky.

Near the center of the sky is the constellation Hokupa, or Leo. Its bright stars form a reverse question mark, making it easy to spot. The zodiacal constellations are the only constellations that the sun, moon and visible planets move through.

At the bottom of the Hawaiian starline Kaiwikuamo‘o is a small but significant constellation, Hanaiakamalama, or the Southern Cross. Navigators can use Hanaiakamalama to determine south.

This constellation is also important for establishing the latitude of the Hawaiian Islands. As mentioned in last month’s column, when Hanaiakamalama is in the upright position, a navigator can measure the distance between its top star and bottom star and when the same distance can be established between the bottom star and the horizon below, this confirms one’s location at the latitude of Kahoolawe. At that point, the navigator can simply turn the canoe downwind, allowing the wind to sail the canoe toward the Hawaiian Islands.

Morning observing

Throughout May, daylight will start to fill the sky around 5:30 a.m., and sunrise will occur just before 6 a.m. Early morning stargazers will be able to see Mars and Saturn in the southern sky. For stargazers with a keen eye, the faint planet Mercury will be rising around 4:45 a.m. in the east.

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 (www.imiloahawaii.org), a center for informal science education at the University of Hawaii at Hilo, showcasing astronomy and Hawaiian culture as parallel journeys of human exploration.