July brings a transition between two celestial star families as Kaiwikuamo‘o (the Backbone) works its way toward the western horizon and Manaiakalani (the Fishhook) appears in the east.
Kaiwikuamo‘o stretches north to south from Hokupa‘a (Polaris), identifying the north celestial pole, to Hanaiakamalama or Newe, the Southern Cross, pointing toward the south celestial pole.
In the center of this north-south star family is the Spring Triangle made up of Hokule‘a (Arcturus), Hikianalia (Spica) and Hokupa (Regulus). Manaiakalani is made up of a trio of stars that form the Summer Triangle rising in the northeast: Keoe (Vega), Pira‘etea (Deneb) and Humu (Altair). The southeastern horizon of this celestial star ohana is dominated by Kamakaunuiamaui (Scorpius), Pimeo (Sagittarius) and Kai‘a, also known as the Milky Way.
On June 21 the sun hovered above its northern boundary Kealanuipolohiwaakane, the Tropic of Cancer, at 23.5 degrees north latitude, marking the first day of summer and the beginning of the annual hurricane season.
Some 500 miles west- northwest of Hawaii island and situated on the Tropic of Cancer lies the lonely island of Mokumanamana, or Necker Island. Though it is not officially confirmed, archaeological evidence suggests that this approximately 46-acre spot is the westernmost island in the Hawaiian Island chain to have been settled by oceanic explorers moving downwind from the eight major Hawaiian Islands. To date there is no other evidence of settlement for the remaining western islands of the Papahanaumokuakea Marine National Monument, ending in Kure Atoll.
Approximately 55 cultural sites have been identified on Mokumanamana, and 33 are believed to have been for religious worship.
In 1857 Kamehameha IV sent Capt. John Paty to claim the island for the Hawaiian kingdom. From 1923 to 1924 Cmdr. Samuel Wilder King led a survey of the island conducted by archaeologist Kenneth Emmory. In 2005 the sailing canoes Hokulaka‘i and Hokule‘a visited Mokumanamana. This summer the Kawaihae-based canoe Makali‘i will return to Mokumanamana to train a new generation of navigators in the tradition of oceanic exploration.
Moon landing celebrations
July 20 marks the 50th anniversary of the Apollo 11’s moon landing — the first time humans set foot on the moon.
Events occurring across the islands to commemorate the anniversary will take place July 20 at ‘Imiloa Astronomy Center, Hilo, 10 a.m.-3 p.m.; Windward Community College, Kaneohe, 10 a.m.-4 p.m.; and Bishop Museum, Honolulu, 10 a.m.-3 p.m.
Featured Mauna Kea discovery
As we celebrate the in-person exploration of our own moon, we continue to explore the other moons of the solar system using our observatories, including those here in Hawaii. Using data taken with the W.M. Keck Observatory accompanied with visible-light observations with the Hubble Space Telescope, astronomers looked at the notable surface features of Europa, Jupiter’s enigmatic icy moon, and found table salt.
Europa has intrigued astronomers for decades. Since we first closely observed the moon with the Voyager and Galileo spacecraft, we have detected strong evidence of a subsurface ocean on it. The presence of this ocean leads many astrobiologists to consider Europa to be the most likely place for us to find life elsewhere in our solar system.
According to an article last month in the journal Science Advances, astronomers have detected the presence of salt on the surface of Europa’s ocean. While we often think about table salt as an ingredient for cooking, it is also an essential component of ocean water. This discovery suggests that Europa’s ocean may be similar to Earth’s ocean; and as we know here in Hawaii, the ocean is full of all forms of life.
Evening observations
In our early evening hours we will be able to view two of our great navigational star lines. Kaiwikuamo‘o will still be stretching over our heads connecting the north star, Hokupa‘a, down to the Southern Cross. July will be our last month this year when we can see the Southern Cross in our early evening sky. At the same time, our summer star line, Manaiakalani, will be rising in the eastern sky.
Views of the Milky Way are spectacular during the summer months in Hawaii. In the early evening, when we look toward the shape of Kamakaunuiamaui, also known as Maui’s Fishhook, we see an area of the Milky Way band commonly called “the bulge,” which refers to the central regions of the Milky Way.
The entire band is illuminated by the combined light of millions of stars, most of which are too far away for us to see with our naked eye. However, a small telescope or even a pair of binoculars will allow us to see a multitude of stars in the Milky Way band, especially on clear dark, moonless nights with little light pollution.
Rising in Manu Malanai, or the southeast, will be the notable planets of Jupiter and Saturn. Jupiter, being the largest of the gas giant planets, is also one of the brightest objects in our night sky and will stand out against the backdrop of the Milky Way. Saturn will be brightest on July 9 when it’s at opposition. Opposition occurs when an outer planet (farther from the sun than Earth) is lined up with Earth and the sun. Saturn is at its closest physical position to Earth on July 9; it will rise at the same time as the sun sets and will be in the sky the entire evening.
Morning observations
In early July the sun will rise just before 6 a.m. At around 5:30 a.m. the notable star cluster Makali‘i, or Pleiades, will be visible, rising out of the east. Trailing behind this famous open cluster, we can catch the famous shape of Heihieonakeiki (Orion), rising exactly in the east just before the sun rises.
JULY SKYWATCH MAP 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.
