2017 Astronomy Highlights
Every year Bishop Museum’s J. Watumull Planetarium (Honolulu Hawai‘i) provides a calendar of astronomical events specifically for Hawaii’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..
In addition, there are certain celestial events that are specific to Hawai‘i. These include the date of Makahiki (Hawaiian New Year), which is determined by the first visible sliver of a moon after the new moon after the rising of the Pleiades at sunset (which occurs on November 17 each year).
This calendar also provides the dates and times for ‘Lāhaina Noon’ for many locations in the islands. Lāhaina 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. Since all of main Hawaiian Islands are below the tropic of Cancer, all of them have two ‘overhead sun’ days a year.
In addition this yearly overview, Bishop Museum provides star maps for each month of the year for Hawaii’s latitude, and a monthly article (“Skywatch”) that covers the astronomical highlights of the Hawaiian night sky for each month. These resources are available at the Bishop Museum Planetarium website:
Astronomy Events 2017
Earth at perihelion. This occurs at 4:17 a.m. January 4 Hawai‘i Standard Time. On this day, the earth is only 91.5 million miles from the sun, compared an average distance of 93 million miles. (At aphelion, in July, earth is 94.5 million miles from the sun).
Like all planets, the earth’s orbit is not a perfect circle but rather 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, while 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.
Chinese New Year
Chinese New Year occurs two new moons before the first day of spring, which occurs on March 20 this year.
Penumbral Lunar Eclipse
In a penumbral eclipse, on the other hand, no part of the moon goes into the dark inner shadow of the earth. The moon moves only into the outer shadow of the earth, missing the dark inner shadow of the earth entirely. This outer shadow, called the “penumbra,” gives it name to this flavor of lunar eclipse. During a penumbral eclipse, you will see virtually no change in the moon’s brightness; the outer shadow of the earth is too faint to darken the lunar disc. This can’t be stressed enough: PENUMBRAL LUNAR ECLIPSES ARE NON-EVENTS. You will see no change in the brightness or color of the moon during a penumbral lunar eclipse.
Comet 45P/Honda-Mrkos-Pajdusakova will be heading back to the outer solar system this February. In the dawn sky, look toward the constellations Aquila and Hercules to get a gimpse of the comet.
On February 11, it will reach its closest point to Earth at 7.7 million miles.
Annular solar eclipse
(NOT VISIBLE IN HAWAI‘I)
An annular solar eclipse occurs when the moon crosses the solar disk at a point in the moon’s orbit where the moon is further than average from the earth. Being a little further away than normal, the moon is a little smaller than normal, and not large enough to block out the sun’s disc even when the moon is dead-center in the middle of the sun’s disc. So, a ring of sunlight shines around the moon (‘annulus’ comes from the Latin word for ‘ring’).
As long as any sunlight shows around the moon, there is not the awesome sense of the earth going dark in the middle of the day; in fact, an annular eclipse can occur overhead without people noticing it.
The path of the annular eclipse moves south-central Africa. Nations in the path of annularity include Gabon, the Congo, the Democratic Republic of Congo, Tanzania, and Mozambique. It will also pass over the islands of Madagascar and Reunion.
As with a total eclipse, the areas for thousands of miles on each side of the annular eclipse will see a partial eclipse. Unique to this eclipse: only Africa will see any portion of this eclipse, and all of Africa will see some degree of a partial eclipse.
Start of Daylight Saving Time for most of continental US and Canada. As of this day, the east coast is six hours ahead of the Hawaiian Islands and the west coast is three hours ahead of Hawai‘i. The Hawaiian Islands do not observe Daylight Saving Time.
Spring begins at 6:31 p.m. Hawai‘i Standard Time on March 20 (04:31 on March 20 Universal Time).
Jupiter in opposition. The planet is brighter than 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, the earth in the middle, and the planet. During opposition, a planet rises at sunset, is high at midnight and sets at dawn.
Easter Sunday. The Sunday after the first full moon after the first day of spring.
Saturn in opposition
As with Jupiter in early April, Saturn shines at its brightest as it hits opposition on June 15. There is a straight line between sun, earth and Saturn; the ringed planet rises at sunset, is overhead all night, sets at dawn.
Earth at aphelion, furthest point from the sun in the earth’s yearly orbit.
Summer begins on June 20 at 12:35 a.m. Hawai‘i Standard Time (22:35 on June 20 Universal Time). This is the longest day for the northern hemisphere and the shortest for the southern hemisphere.
Partial Lunar Eclipse (not visible in the Hawaiian Islands)
A partial lunar eclipse occurs when the Moon passes through the Earth’s partial shadow, or penumbra, and only a portion of it passes through the darkest shadow, or umbra. During this type of eclipse a part of the Moon will darken as it moves through the Earth’s shadow.
The eclipse will be visible throughout most of eastern Africa, central Asia, the Indian Ocean, and Australia.
For the August 7 eclipse, only a small portion of the moon will go into the deep inner shadow of the earth; viewers will see only a small ‘bite’ taken out of the moon at the peak of the eclipse, as about 20 per cent of the moon will go into the umbra.
We will just miss this lunar eclipse in the Hawaiian Islands. The full moon sets in Hawaii at 5:55 a.m. that morning of August 7, right as the penumbral phrase is beginning. (The penumbral phase, as the moon starts to enter the faint outer shadow of the earth, is not visible to the naked eye anyway, even were the moon not setting as the phase begins). By the time the partial phrase (the time when a lunar eclipse becomes visible) begins at 7:25 a.m. Hawai‘i time, the moon will be well below the horizon in Hawai‘i.
The peak of the lunar eclipse occurs at 18:20 Universal Time on August 7; this is 8:20 a.m. on August 7 Hawaii Time, though again we will not see it since the moon will have already set more than two hours earlier.
In Mumbai, India, as an example, the peak of the lunar eclipse will occur around midnight local time on the evening leading from August 7 to august 8. Again, about 20 per cent of the moon will be in the earth’s shadow at the peak, making the moon look like a cookie with a bite taken out.
Total Solar Eclipse
A total solar eclipse occurs when the moon completely blocks the Sun which reveals the Sun’s outer atmosphere – the corona. This is a rare event for those in the United States. This event is being called “The Great American Eclipse,” as it will pass right across the center of the continental US. Cities along the path of totality include Salem, Oregon; Nashville Tennessee; and both Columbia and Charleston, South Carolina.
The last total solar eclipse visible in the continental United States occurred in 1979 and the next one will not take place until 2024. The path of totality will begin in the Pacific Ocean and travel through the center of the United States. The total eclipse will be visible in parts of Oregon, Idaho, Wyoming, Nebraska, Missouri, Kentucky, Tennessee, North Carolina, and South Carolina before ending in the Atlantic Ocean. A partial eclipse will be visible in most of North America and parts of northern South America.
In Salem, Oregon, the total eclipse runs from 10:17 to 10:19 a.m. on August 21 Pacific Daylight Time (it will be total there for 1 minute and 53 seconds). In Nashville, 1:27 to 1:29 p.m. Central Daylight Time; and in Charleston, the total phrase runs from 2:46 to 2:49 p.m. Eastern Daylight time, for a total of 1 minute and 39 seconds of totality.
In the Hawaiian Islands, we will not see a total solar eclipse; we’ll have to wait till 2106 for a total eclipse over our islands! We will, however, see a partial solar eclipse right at dawn.
The sun will rise in Honolulu at 6:20 a.m. on the morning of August 21 in partial eclipse, with about one-third of the sun’s disk blocked by the moon. For the next hour, viewers using safe viewing devices (and a clear eastern horizon – the sun will still be low in the east, in this hour after dawn) will see the moon slowly uncover the sun. By 7:25 a.m. in Honolulu the eclipse will be over.
As this eclipse ends at 7:25 Hawaii Standard Time on August 21 in the islands, it will be getting underway on the North American continent as the shadow of the moon races across our planet. 7:25 a.m. HST is 12:25 p.m. Central Daylight Time in Nashville, for example, and at that time the partial eclipse will be underway in Nashville; the eclipse in Nashville goes total at 1:27 p.m. CDT on August 21, which is 8:27 a.m. Hawaii Time if you wish to watch it here in the islands on a webcast.
Please note that itis never safe to view a partial solar eclipse directly; the safe viewing glasses carried by Bishop Museum’s Shop Pacifica and other venues are a good means of viewing solar eclipses.
Autumn begins at 4:22 a.m. on September 22 Hawai‘i Standard Time (14:22 Universal Time on September 22.)
Daylight Saving Time ends at 2 a.m. for most of continental US and Canada. As of this day, the east coast is five hours ahead of the Hawaiian Islands and the West Coast is two hours ahead.
Conjunction of Venus and Jupiter
The two bright planets will be extremely close, appearing only 0.3 degrees apart. Look for this impressive pairing in the Eastern sky just before sunrise.
Makahiki (start of the Hawaiian year). To mark the start of the Makahiki season: 1) wait for the star cluster of the Pleiades to rise at sunset, which occurs on November 18) wait for the new moon that follows this sunset rising of the Pleiades, which occurs in 2017 on December 3) wait for the first visible crescent moon that follows this new moon. This year, this slender crescent should be visible in the west at dusk on December 1, thus marking the start of the Makahiki season and of the Hawaiian year.
The only Supermoon of 2017. The moon will be a little closer to earth than average for a full moon, and thus will be 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.
Supermoon background: the term ‘supermoon’ is a recent invention and has received a fair amount of media attention in the last few years. The term 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 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 a just a full moon that occurs in the same day that the moon is at perigee. Since it’s a little closer than usual, the moon appears a little large than a ‘normal’ full moon.
The astrologer who coined the term ‘supermoon’ actually uses the term in reference to both new moons and full moons that occur near perigee. That said, there has been very little interest is ‘super new moons’ since you cannot see a new moon.
Winter starts at 12:45 a.m. Hawai‘i Standard Time on December 21 (10:45 Universal Time on December 21).
For all meteor showers, the viewing will be better after midnight. These repeating annual events are caused as the earth enters into debris left over from a specific comet (or, in the case of the Geminids, an asteroid). As the earth goes around the sun, our planet runs into the same debris at the same time each year. This is why these showers occur at the same time each year. After midnight, the part of the earth that you are on is facing toward the debris that causes the meteor shower. This is why all meteor showers are better after midnight.
Meteor star showers are named for the constellation where the meteors appear to come from. The Lyrid shower in named for Lyra, the harp, for example. (The Quadrantid Shower refers to an old constellation called Quadrans Muralis, which is now part of Bootes). Generally these constellations are rising in the east during the prime post-midnight viewing time for a shower. That said, don’t just look east – scan the entire sky for shooting stars.
To view shooting star showers, just find a dark location (as little city light as possible) and get comfortable (a lawn chair is a good idea).
More on meteor showers: http://www.amsmeteors.org/meteor-showers/meteor-shower-calendar/
Quadrantid Meteor shower
Peak night: January3-4, 2017
The Quadrantids have a sharp, short peak, lasting only a few hours.
If you want to try your luck, the best viewing should be in the predawn hours on January 3 (i.e. really early on January 3, from 12:01 a.m. till dawn) and during the predawn hours January 4 (again from 12:01 a.m. ‘til dawn).
The streaks of the Quadrantids appear to come from the constellation of Bootes the Herdsman, in the northeast. “Quadrant Muralis,” or “Mural Quadrant,” an old name for part of the constellation of Bootes. This was 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.
Lyrid Meteor Shower
Best viewing times: 21:01 am to dawn on April 21 and on April 22
The best viewing times for the Lyrids will be from 12:01 am to dawn early on April 21, and from 12:01 am to dawn early on April 22, Hawai’i Standard Time. The shower is active from April 16 – 25. While not one of the strongest showers, the Lyrids can produce up to twenty meteors per hour. The Lyrids come from the debris of Comet C/1861 G Thatcher.
Eta Aquarid Shower
Peak: evening of May 6-7, 2017. The portion of Aquarius where the shoot stars radiate rises above the horizon around 3:45 a.m. This is a light shower, 10 to 30 meteors or so per hour when viewed from the northern half of our planet. One claim to fame: this shower is one of two showers caused by debris from Halley’s Comet, along with the Orionids in October. The full moon occurs on May 10 this year, so there will be some lunar inteference with this meteor shower.
Perseid Meteor Show
Peak: early in the morning on August 11, from 12:01 am till dawn; and again early in the morning of August 12, 12:01 a.m. till dawn.
The Perseids are the most famous meteor shower, with up to 80 per hour. The Perseids often leave long trails. The shower is generated by debris from Comet 109 P Swift Tuttle. This comet takes 130 years to orbit the sun, and passed through the earth’s part of the solar system back in 1992, leaving lots of fresh comet debris that led to particularly good showers.
Orionid Meteor Shower
Peak: night of October 21-22; the night of October 20-21 should also be good. Active period: October 4- November 14. Like the Eta Aquarids in May, this one is caused by debris from Halley’s Comet. Up to 20-25 meteors per hour.
Leonid Meteor Shower
Peak: Nights of November 17-18; active period is November 5 – 30. The Leonids have an intense peak every 33 years and were responsible for the greatest meteor shower over Hawai‘i in recent times, the 2001 shower. Prior to that 2001 spectacle, the 1966 shower was one of the greatest on record.
Excellent lunar conditions during the peak of this shower – new moon.
Geminid Meteor Shower
Peak: nights of December 13-14, from 12:01 a.m. to dawn. Active period: December 6 – 19. One of the best showers; and we in Hawai‘i often have good weather in December to see it. This meteor shower is a rarity in that it is caused by debris from an asteroid (3200 Phaethon) rather than by comet debris.
In the tropics the sun passes overhead twice during the year. On these two days, at local noon, the sun will be exactly overhead and an upright object such as a flag pole will have no shadow. This phenomenon only occurs in the tropics; the sun is never overhead in any other part of the planet. The northern reaches of the Hawaiian Islands, such as Midway Island, are north of the tropics and do not experience the overhead sun.
The ‘overhead sun’ date varies depending on how far north or south you are in the tropics. Thus, for Līhu‘e on Kaua‘i, this occurs on July 11, at 12:42 p.m. Further south, on the Island of Hawai‘i, the overhead sun date occurs on July 24 (12:26 p.m. for Hilo, 12:30 p.m. for Kailua Kona).
Here in the islands a term we often use for zenith noon is “Lāhaina Noon.” This is a modern term, selected by Bishop Museum in a 1990 contest held to select a name for the zenith noon phenomenon. The term “Lā haina” means ‘cruel sun’ in Hawaiian, and while the sun in the islands is almost never cruel, it can be pretty intense as it shines directly down from the zenith.
Another phrase that one hears in Hawai‘i for the zenith sun is “kau ka lā i ka lolo,” which translates as “the sun rests on the brains.” This expression is discussed in the book 1972 book Nānā I Ke Kumu (Pukui et. al.) as being a “phrase designating high noon; the time when ‘the sun is directly overhead and the shadow retreats into the body’… In view of all this, what we now call ‘high noon’ was thought to be a time of great mana (spiritual power).”  While this passage has be cited by some writers to suggest that “kau ka lā i ka lolo” is thus the traditional Hawaiian term for the ‘zenith sun,’ the phrase seems to refer to “high noon” on any day, and not specifically to those two days a year when the sun is exactly overhead. Thus, in Honolulu on May 26 at 12:28 p.m., one can certainly use the term “kau ka lā i ka lolo” to describe the sun’s position as it sits exactly overhead. However, that same expression “kau ka lā i ka lolo “can be used to describe the sun’s position on any other day at local noon (at least for the non-winter months, when the sun is quite high in the sky at local noon), and does not specifically refer to the phenomenon of ‘zenith noon’ itself.
The chart below gives the overhead sun dates for a number of locations.
2017 Lāhaina Noon days and times
|Līhue||May 31 12:35 p.m.||July 12 12:42 p.m.|
|Kāne‘ohe||May 27 12:28 p.m.||July 15 12:37 p.m.|
|Honolulu||May 26 12:28 p.m.||July 16 12:37 p.m.|
|Kaunakakai||May 25 12:25 p.m.||July 16 12:34 p.m.|
|Lāna‘i City||May 23 12:24 p.m.||July 18 12:34 p.m.|
|Lahaina||May 24 12:23 p.m.||July 18 12:33 p.m.|
|Kahului||May 2412:22 p.m.||July 18 12:32 p.m.|
|Hana||May 23 12:20 p.m.||July 18 12:30 p.m.|
|Hilo||May 18 12:16 p.m.||July 24 12:27 p.m.|
|Kailua-Kona||May 18 12:20 p.m.||July 24 12:30 p.m.|
|South Point Island of Hawai‘i||May 14 12:19 p.m.||July 27 12:28 p.m.|
|New Moon||First Quarter||Full Moon||Third Quarter|
 Nānā I Ke Kumu, V. 1. Mary Pukui, E.W. Haertig, Catherine E Lee; Honolulu, Hui Hānai Press, 1972 pp 123-4.