Annual Astronomy Highlights
Annual Astronomy Highlights
Every year Bishop Museum’s J. Watumull Planetarium (Honolulu, Hawaiʻi) provides a calendar of astronomical events specifically for Hawaiʻi’s location and time zone.
Most sources that list the times for moon phases, meteor shower peaks, the start of the seasons, and other events provide that information in Universal Time (UT), which is ten hours ahead of Hawaiian time. We’ve adjusted all times and dates on our calendar to reflect when they occur in Hawaiʻi Standard Time (HST).
This calendar also provides the dates and times for lāhainā noon for many locations in the Islands. Lāhainā noon is the term for the two days each year when the sun is exactly overhead. This only occurs in the tropics, and the dates vary depending on latitude.
In addition to this yearly overview, Bishop Museum provides star maps for each month of the year for Hawaiʻi’s latitude. This resource is available on the Bishop Museum Planetarium website: https://www.bishopmuseum.org/skymaps/
January 2, 2021
Earth at Perihelion
This occurs at 3:50 a.m. on January 2, Hawaiʻi Standard Time. On this day, Earth is only 91.4 million miles from the Sun, compared to an average distance of 93 million miles. (At aphelion, in July, Earth will be 94.5 million miles from the Sun).
Like all planets, Earth’s orbit is not a perfect circle but is elliptical, or like an oval. Earth reaches perihelion, its closest approach to the Sun, in early January each year. Some people think that the change in the seasons is due to how close we are to the Sun. However, what really matters here is the tilt of the Earth. Each January, although we are closer to the Sun than at any other time of the year, the Northern Hemisphere is tilted away from the Sun, and so we experience winter.
January 2–3, 2021
Quadrantids Meteor Shower Peak
The Moon will rise as a bright waning gibbous at 9:45 p.m., reducing visibility to only the brightest meteors.
The Quadrantids have a sharp, short peak, lasting only a few hours. The streaks of the Quadrantids appear to come from the constellation of Boötes (Boo-oh-tees), the Herdsman, in the northeast. “Quadrant Muralis,” or “Mural Quadrant,” is an old name for part of the constellation of Boötes. This is one of the now-lost constellations that were done away with when the International Astronomical Union divided the sky into 88 officially recognized constellations in 1922.
February 12, 2021
Chinese New Year
Chinese New Year occurs two new moons before the first day of spring, which occurs on March 19 this year.
February 18, 2021
NASA’s Perseverance Rover Lands on Mars
At approximately 10:30 a.m. Hawaiʻi Time, NASA’s Perseverance rover will land on Mars after spending the previous seven months hurtling through space. Perseverance’s primary mission is to look for signs of ancient bacterial life on Mars. The landing site is in Jezero Crater, a dried up lake bed that scientists think could be among the best locations on Mars to look for signs of ancient life. Perseverance will collect and store the most compelling rock samples to be collected and returned to Earth as part of a future mission to Mars. Accompanying Perseverance is Ingenuity, a helicopter which aims to test the first powered flight on Mars. Learn more about Perseverance from NASA’s mission overview web page: https://mars.nasa.gov/mars2020/mission/overview/
March 14, 2021
Daylight Saving Time Starts for US Continent
Start of Daylight Saving Time for most of the continental US and Canada. As of this day, the East Coast is six hours ahead of the Hawaiian Islands (instead of five) and the West Coast is three hours ahead of Hawai‘i (instead of two). The Hawaiian Islands do not observe Daylight Saving Time.
March 19, 2021
March Equinox; Northern Hemisphere Spring Begins
At 11:37 p.m. HST, the Sun crosses the celestial equator (Earth’s equator projected into space) as its path across the sky (the ecliptic) appears to move farther north. On this day the Sun rises due east and sets due west and the length of day and night are approximately equal. The equal day and night is where the word equinox comes from. The Latin word aequus means equal, and nox means night.
April 21–22, 2021
Lyrid Meteor Shower Peak
A waxing gibbous Moon will brighten the skies until it sets at about 3:00 a.m., reducing visibility of meteors.
The Lyrids are named for the constellation Lyra, the Harp, where the meteor shower appears to originate from. As with all meteor showers the best viewing times for the Lyrids will be from 12:01 a.m. to dawn (5:45 a.m.), early on April 22. They should start being visible around 10 p.m. while Lyra rises in the east. The shower is active from April 16–25, so if you miss the peak the night of the 21st you may still spot a few in the days before and after. While not one of the strongest showers, the Lyrids can produce up to twenty meteors per hour. The Lyrids are generated from the debris of Comet C/1861 G Thatcher.
April 26, 2021
Supermoon and Full Moon
This supermoon is the first of two in 2021. The other occurs May 26. The Moon will be a little closer to Earth than average for a Full Moon, and thus will appear a little bigger and brighter than the norm.
A Moon is officially “full” when the Sun, Earth, and Moon are in a straight line, with the Earth in between the two other celestial bodies, allowing for observers on Earth to receive the maximum sunlight reflected off the Moon, illuminating its whole disk.
Supermoon background—The term “supermoon” is a recent invention and has received a fair amount of media attention in the last few years. It has come to refer to a full moon that occurs when the Moon is near its closest point to Earth in its slightly oval path around our planet. Since the Moon’s path is oval, or elliptical, it can be as close as 225,600 miles from us or as far from us as 252,000 miles. When the Moon is at the closest point to Earth in its monthly path around the Earth, it is said to be at perigee. A supermoon is just a full moon that occurs on the same day that the Moon is at perigee. Since it’s a little closer than usual, the Moon appears a little larger and a little brighter than a “normal” full moon.
The astronomer who coined the term supermoon uses the term in reference to both new moons and full moons that occur near perigee. That said, there has been very little interest in “super new moons,” since you cannot see a new moon. Incidentally, there are two super new moons in 2021: on November 4 and December 3.
May 5–6, 2021
Eta Aquarid Meteor Shower Peak
The Moon doesn’t rise until 3:13 a.m. and is a waning crescent so it should not impact visibility much if at all.
Though this meteor shower’s peak is from May 5–6, it is active from April 19 to May 20 each year. The portion of Aquarius from which the meteors radiate rises above the horizon around 3:00 a.m., but meteors will be visible before that. This is a light shower of about 20 to 40 meteors per hour. One of its claims to fame: this shower is one of two showers caused by debris from Halley’s Comet, along with the Orionids in October.
May 14–30, 2021
First Lāhainā Noon Season of the Year
May 14 is the first occurrence of lāhainā noon in Hawaiʻi for 2021. During lāhainā noon upright objects such as a flag pole will cast no shadow becuase the Sun is exactly 90o overhead. South Point on Hawaiʻi Island experiences it first on May 14 and over the next two weeks locations farther north through the islands will experience it too. As we move through May, getting closer to the June Solstice when Earth’s northern half is tilted toward the Sun, the location where the lāhainā noon phenomena occurs moves north as well. After the Solstice in June, Earth’s northern half begins to tilt away from the Sun and the location where lāhainā noon occurs moves south, passing through the Hawaiian Islands again in July. Honolulu’s will be on May 26 at 12:29 p.m. For more information on lāhainā noon and when it occurs for other parts of Hawaiʻi, click here.
May 25–26, 2021
Total Lunar Eclipse
From the night of May 25 into 26, Hawaiʻi will be treated to a total lunar eclipse! A lunar eclipse occurs when the Moon passes through the Earth’s shadow cast into space by light from the Sun. For this eclipse, the Moon begins to move into Earth’s shadow at 11:45 p.m. At 1:18 a.m. the Moon will begin to turn red as it enters the center of Earth’s shadow. The red color comes from sunlight passing through Earth’s atmosphere, the same reason sunsets produce a red color. At 1:25 a.m. the red color will fade as the Moon begins to move out from Earth’s shadow. At 2:52 a.m. the eclipse ends. Lunar eclipses only occur during the full moon phase because that is when the Sun, Earth, and Moon are in a line. This does not happen every full moon because the Moon’s orbit is tilted by about 5o in relation to Earth’s orbit around the Sun, so it is usually above or below the shadow cast by Earth. Occasionally things line up just right, so that the Moon passes through the Earth’s shadow, or umbra. This causes a total lunar eclipse. The edge of the umbra is called the penumbra; sometimes during a lunar eclipse the Moon just passes through the penumbra and it looks very much like a normal full moon because it’s not the darkest part of the shadow. This is called a penumbral lunar eclipse.
June 20, 2021
Summer begins on June 20 at 5:32 p.m. HST for the Northern Hemisphere. This day has the most hours of sunlight of the year for the Northern Hemisphere and the fewest for the Southern Hemisphere. The solstice officially occurs at 5:32 a.m. HST, because that is when the Sun is directly overhead at the Tropic of Cancer (23° 30ʹ N Latitude). The Sun will rise at its point farthest north of east and will set at its farthest north of west. After this day the Sun will rise and set closer and closer to due east and west heading toward the equinox in late September.
June 10, 2021
Annular Solar Eclipse (not visible in Hawaiʻi)
This eclipse will not be visible in Hawaiʻi, unfortunately. A solar eclipse occurs when the Moon passes between Earth and the Sun, and thus can only occur during the new moon phase. The Moon casts its shadow on Earth and if you are standing on Earth in the Moon’s shadow, the Sun is at least partially blocked by the Moon. The distance from the Moon to the Earth changes during the Moon’s monthly orbit around the Earth. If the Moon is near its closest to the Earth (perigee), the whole disk of the Sun is blocked, and a total solar eclipse occurs. This is because near perigee, the Moon and Sun appear about the same size from Earth’s perspective. Really, the Sun is MUCH larger, about 400 times the Moon’s diameter, but also about 400 times farther away, causing the illusion of being about the same size in the sky when viewed from Earth. Quite an amazing cosmic coincidence! If the Moon is at a farther distance, the apparent size of the Moon is not large enough to cover the whole Sun, so a ring of the Sun is visible around the edge of the Moon. This ring is where the word annular, or ring shaped, comes from. Annulus is Latin for ring.
July 5, 2021
Earth at Aphelion
At 12:27 p.m. HST the Earth will be 94.5 million miles from the Sun, the farthest point in its orbit.
Like all planets, Earth’s orbit is not a perfect circle, but rather an oval. Earth reaches aphelion, its farthest point from the Sun, in early July each year. Some people think that the change in the seasons is due to how close we are to the Sun. However, what really matters is the tilt of the Earth. Each July, although we are farther from the Sun than at any other time of the year, the Northern Hemisphere is tilted toward the Sun, receiving more direct sunlight, and so we experience summer.
July 11–27, 2021
Lāhainā Noon Season
July 11 marks the beginning of the second occurrence of lāhainā noon in Hawaiʻi for 2021. During lāhainā noon, upright objects such as a flag pole will cast no shadow becuase the Sun is exactly 90o overhead. Kauaʻi experiences it first on July 11 and over the next two weeks locations farther south through the Islands will experience it too. As we move through July, away from the June Solstice, Earth’s northern half begins to tilt away from the Sun and the location where the lāhainā noon phenomena occurs moves south. Before the Solstice in June, Earth’s northern half begins to tilt toward the Sun and the location where lāhainā noon occurs moves north, passing through the Hawaiian Islands in May. Honolulu’s will be on July 16 at 12:38 p.m. For more information on lāhainā noon and when it occurs for other parts of Hawaiʻi, click here.
August 1, 2021
Saturn at Opposition
The planet Saturn is brighter than at any other time of the year and will be visible all night. When a planet is in opposition, there is a straight line between the Sun, Earth, and the other planet, with Earth being in the middle. This allows for the maximum reflection of sunlight from the planet to bounce back to us on Earth. During opposition, a planet rises at sunset, is high at midnight, and sets at dawn. This is a great time to view Saturn through a telescope and enjoy its beautiful rings.
August 11–12, 2021
Perseid Meteor Shower Peak, Planets on Parade
The Moon is a waxing crescent and will set at 9:40 p.m., providing ideal meteor viewing conditions.
The Perseid Meteor Shower is active from July 13 to August 26, but the most active and fruitful dates are August 11 and August 12. The Perseids are the most famous and bountiful meteor shower with up to or over 100 meteors per hour, often leaving long trails across the sky. The shower is generated by debris from Comet 109 P Swift Tuttle. This comet takes 130 years to orbit the Sun. It most recently passed through the Earth’s part of the solar system back in 1992, leaving lots of fresh comet debris that leads to particularly good showers.
The night of August 11 provides lots to view this year. As the Sun sets look to the western horizon for a beautiful lineup of three planets and the Moon. Right after the Sun goes down, catch Mercury before it sets at 7:40 p.m. Just above Mercury you’ll find a faint Mars, and above Mars,Venus and the waxing crescent Moon: a beautiful sight even in small binoculars with shadows cast along the mountains and craters. Then with moonless skies after 9:40 p.m., conditions will be ideal for watching meteors, plus Jupiter and Saturn are both close to opposition, at their best and brightest of the year. The best meteor viewing will be after midnight but some meteors will be visible in the evening.
August 19, 2021
Jupiter at Opposition
The planet Jupiter is brighter than at any other time of the year and will be visible all night. When a planet is in opposition, there is a straight line between the Sun, Earth, and the other planet, with Earth being in the middle. This allows for the maximum reflection of sunlight from the planet to bounce back to us on Earth. During opposition, a planet rises at sunset, is high at midnight, and sets at dawn. During this time, a pair of binoculars will allow you to see the Galilean Moons—the four largest moons of Jupiter.
September 22, 2021
September Equinox; Autumn Begins in the Northern Hemisphere
At 9:21 a.m. the Sun crosses the celestial equator (Earth’s equator projected into space) as its path across the sky (the ecliptic) appears to move farther south. On this day the Sun rises due east and sets due west and the length of day and night are approximately equal. The equal day and night is where the word equinox comes from. The Latin word aequus means equal, and nox means night.
October 7–8, 2021
Draconid Meteor Shower Peak
The Moon sets at 7:32 p.m., providing dark skies for this shower this year.
In Hawaiʻi, the constellation Draco, for which the Draconid Meteor Shower is named, sets at about midnight in early October due to our low latitude. This means the meteors will be most active for us from after sunset until about midnight. While the Draconids have produced some spectacular showers in the past, it is typically not among the more impressive meteor showers. The shower is caused by debris from comet 21P/Giacobini-Zinner.
October 21–22, 2021
Orionid Meteor Shower Peak
Just one day past full, the Moon will be big and bright all night long, not ideal for meteor viewing.
The active period for this shower is September 23–November 27, though the peak, producing about 20–25 meteors an hour, will be on October 20 and 21. Like the Eta Aquarids in May, this meteor shower is caused by debris from Halley’s Comet.
November 7, 2021
Daylight Saving Time Ends
Daylight Saving Time ends at 2 a.m. for most of the continental US and Canada. As of this day, the East Coast is five hours ahead of the Hawaiian Islands (instead of six) and the West Coast is two hours ahead (instead of three).
November 16–17, 2021
Leonid Meteor Shower Peak
The Moon will be two days from full, not ideal for meteor viewing. As with all showers, the best viewing is after midnight until dawn, but some meteors could be visible before then.
The Leonids have an intense peak every 33 years and were responsible for the greatest meteor shower over Hawaiʻi in recent times—the 2001 shower. Prior to that 2001 spectacle, the 1966 shower was one of the greatest on record. This year is not expected to produce more than 15 to 20 meteors per hour.
December 4, 2021
Total Solar Eclipse (not visible in Hawaiʻi)
While not visible in Hawaiʻi, this total solar eclipse will see the Moon’s shadow move across Antarctica. A solar eclipse occurs when the Moon passes between Earth and the Sun and thus can only occur during the new moon phase. The Moon casts its shadow on Earth and if you are standing on Earth in the Moon’s shadow, the Sun is at least partially blocked by the Moon. The distance from the Moon to the Earth changes during the Moon’s monthly orbit around the Earth. If the Moon is near its closest to the Earth (perigee), the whole disk of the Sun is blocked, and a total solar eclipse occurs, like this one. This is because near perigee, the Moon and Sun appear about the same size from Earth’s perspective. Really, the Sun is MUCH larger, about 400 times the Moon’s diameter, but also about 400 times farther away, causing the illusion of being about the same size in the sky when viewed from Earth. Quite an amazing cosmic coincidence! If the Moon is at a farther distance, the apparent size of the Moon is not large enough to cover the whole Sun, so a ring of the Sun is visible around the edge of the Moon. This is called an annular eclipse. The word annular comes from the Latin annulus, meaning ring.
December 13–14, 2021
Geminid Meteor Shower Peak
The Moon will not set until 3:18 a.m., so while some meteors will be visible before that, the best viewing time will be from about 3:00 a.m. until dawn, which begins around 6:00 a.m.
The Geminids are one of the best showers to view, as the meteors are very bright and intensely colored. We in Hawaiʻi are lucky as we often have good weather in December to see it well. This meteor shower is a rarity in that it is caused by debris from an asteroid (3200 Phaethon), rather than by comet debris.
December 21, 2021
Winter begins on December 21 at 5:59 a.m. HST for the Northern Hemisphere. This day has the least hours of sunlight of the year for the Northern Hemisphere and the most for the Southern Hemisphere. The solstice occurs officially at 5:59 a.m. HST, because that is when the Sun is directly overhead at the Tropic of Capricorn (23° 30ʹ S Latitude). The Sun will rise at its point farthest south of east and will set at its farthest south of west. After this day the sun will rise and set closer and closer to due east and west heading toward the vernal equinox in late March.
About the Planetarium
Bishop Museum’s Jhamandas Watumull Planetarium was the first planetarium in Polynesia. Originally called the Kilolani Planetarium, the Watumull Planetarium has served over six million visitors and students since it opened its doors on December 11, 1961. Our Chronos II star machine provides one of the most vivid, realistic recreations of the night sky available today, with 8,500 pinpoint stars and realistic, bright planets. Our Digistar full dome video system covers the entire dome in immersive video, allowing us to fly through the rings of Saturn or into the depths of the Orion nebula.
The planetarium has 70 seats and serves 70,000 people a year. The planetarium focuses on programs about Hawai‘i; a hallmark of its programs is the blending of live and prerecorded elements within each program.