‘Imiloa Astronomy Center
Astronomers using the Canada-France-Hawaii Telescope on Mauna Kea discovered 128 new moons of Saturn. Astronomers from Taiwan, Canada, the U.S. and France used CFHT to monitor Saturn and its surroundings in minute-by-minute detail to discover these moons. These new moons are now recognized by the International Astronomical Union.
All 128 of these newly discovered moons are classified as “irregular moons,” objects that were captured by the host planet early on in the history of the solar system. These new moons are only a few kilometers in size and are likely fragments of larger moons that were violently broken apart by collisions with other Saturn moons or passing comets.
The large number of these small moons relative to Saturn’s large moons also suggests that they formed from collisions within the Saturn system in the past 100 million years, which is recent in astronomical terms. Otherwise, these smaller fragments would have continued to collide with each other and blow themselves to smithereens. Most of these discovered moons are in the Mundilfari subgroup of Saturn’s moons, suggesting this could be the site of this relatively recent collision event.
Saturn now has 274 moons, almost twice as many moons as the other solar system planets combined. This recent discovery has almost certainly cemented Saturn’s status as the solar system’s planet with the most moons. Jupiter has the second-most moons with 95.
More information can be found at phas.ubc.ca/2025-discovery-more- Opens in a new tabsaturnian-moons Opens in a new tab.
Special events
The Lyrids meteor shower will peak in Hawaii on April 21-22, with up to 18 meteors visible per hour. The Lyrids shower is named after the constellation Lyra. This constellation contains Vega, one of the brightest stars in the night sky and a helpful guide to locating the constellation. The shooting stars are created from the debris of the comet Thatcher. The Lyrids meteor shower is the oldest known shower ever recorded, as chronicled in the Zuo Zhuan in 687 B.C.
Evening observing
During the early evening hours of April, stargazers will be able to observe two of the four navigational starlines at the same time: Kekaomakali‘i and Kaiwikuamo‘o.
Kekaomakali‘i, the bailer of Makali‘i, stretches overhead in the western sky. The great celestial bailer starts in the north with the hexagonal shape of Hokulei, a lei of stars, passes in a gentle arc through the stars Nanamua and Nanahope, then to Puana and the brightest star in the evening sky, ‘A‘a, before dropping down to Keali‘iokonaikalewa to form the handle of the bailer.
A bailer is used to scoop out water that might be flooding a canoe; however, Kekaomakali‘i is not a bailer for water, but a bailer for the stars. Over the course of the night, the celestial bailer will scoop up the stars from the horizon in the east and scatter them overhead and carry them to the west. The bailer will scatter the shape of Kaheiheionakeiki, which is also known as Orion the hunter, and the famous star cluster of Makali‘i into the Komohana (west) horizon in the early evening.
The next navigational star family — Kaiwikuamo‘o, the backbone — will be seen toward the Hikina (east). Kaiwikuamo‘o is significant as it stretches all the way from north to south. Starting at Hokupa‘a, the North Star, through Nahiku, the Big Dipper, Kaiwikuamo‘o then follows the arc of Nahiku to Hokule‘a and to Hikianalia, then passes through Me‘e, where it will then drop straight down to Hanaiakamalama, the Southern Cross.
April will be the last month when we will still be able to view the star cluster of Makali‘i in the early evening sky until November when the season of makahiki will begin. The notable cluster will be close to the northwestern horizon in the early evening.
The star cluster of Makali‘i, also known as the Pleiades, is an open cluster that contains thousands of stars. This open cluster was born from a star-forming nebula approximately 100 million years ago. As all of the stars are about the same age, astronomers will use open clusters like Makali‘i to study how different types of stars live out their lifetimes. This cluster is known as Subaru in Japanese, and is the name of the telescope on Mauna Kea run by the National Astronomical Observatory of Japan.
The planets Mars and Jupiter will also be visible in the early evening sky during April.
Morning observing
Throughout April, sunrise will occur between 6 and 6:30 a.m. During these early morning hours, the planets Saturn and Venus will rise from the Hikina (east) horizon. Through a very good pair of binoculars or a telescope, early morning observers can spot the famous rings of Saturn.
Mercury will also rise in the east during the second half of the month. The best day to view Mercury will be April 21, just before sunrise. This is when Mercury will be at its highest point above the horizon in the morning sky. Look for the planet low in the eastern sky just before sunrise. Mercury will be near Venus and Saturn.
In the Hema (south) part of the sky, observers will also find the celestial shape of Kamakaunuiamaui, Maui’s Fishhook. When we look at the bulge of the Milky Way, sitting behind Kamakaunuiamaui, we are looking toward the central regions of our home galaxy. This area is home to our galaxy’s central supermassive black hole, known as Sagittarius A*.
The constellations of Cygnus and Lyra will be high in the sky in the morning hours before sunrise. It was the region of these two constellations where the Kepler space telescope discovered thousands of planets orbiting stars beyond our solar system and fundamentally changed our understanding of exoplanets.
20250219_Skywatch_April_JM[44] by Honolulu Star-Advertiser on Scribd
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.
