Second 2018 Shadowless Lahaina Noon Happens in July in Hawaii

Summary: The second 2018 shadowless Lahaina Noon happens in July in Hawaii as a directly overhead sun at solar noon shines away shadows from vertical objects.

second 2018 Lahaina Noon, July 11-July 27: SS&TC @ShortSleeveClub via Twitter June 1, 2018

The second 2018 shadowless Lahaina Noon happens in July as a directly overhead sun at apparent local solar noon shines away shadows from people and other verticals in the Hawaiian archipelago’s windward islands.

The earliest instance of July 2018’s Lahaina Noon listed by Honolulu’s Bernice Pauahi Bishop Museum occurs Wednesday, July 11, at Lihu’e, Kaua’i. Lahaina Noon is timed for Kaua’i’s second largest town at 12:43 p.m. Hawaii-Aleutian Standard (22:43 [10:43 p.m.] Coordinated Universal Time/Greenwich Mean Time).

The Bishop Museum gives July 2018 Lahaina Noon days and times for eight additional locales in Hawai’i’s windward islands.

Lihu’e, Kaua’i: Wednesday, July 11, at 12:43 p.m. HAST (22:43 UTC/GMT);
Kane’ohe, O’ahu: Sunday, July 15, at 12:37 p.m. HAST (22:37 UTC/GMT);
Kaunakakai, Moloka’i: Tuesday, July 17, at 12:34 p.m. HAST (22:34 UTC/GMT);
Hana, Maui: Wednesday, July 18, at 12:30 p.m. HAST (22:30 UTC/GMT);
Kahului, Maui: Wednesday, July 18, at 12:32 p.m. HAST (22:32 UTC/GMT);
Lahaina, Maui: Wednesday, July 18, a 12:32 p.m. HAST (22:23 UTC/GMT);
Hilo, the Big Island: Tuesday, July 24, at 12:26 p.m. HAST (22:26 UTC/GMT);
Ka Lae (South Point), the Big Island: Friday, July 27, at 12:28 p.m. HAST (22:26 UTC/GMT).

The Bishop Museum notes that an absolute Lahaina Noon does not happen this year at Honolulu, O’ahu, and Kailua-Kona, the Big Island. The museum explains that Lahaina Noon requires the sun’s apparent placement in the sky at 90 degrees over the location. In 2018, the sun only reaches 89 degrees for Honolulu and Kailua-Kona.

The Hawaiian archipelago’s tropical location in the central Pacific Ocean qualifies its windward islands for experiencing an apparently directly overhead sun twice each year. Local latitude explains the range in dates and times for the Hawaiian archipelago’s Lahaina Noon.

The Hawaiian archipelago’s first Lahaina Noon occurs annually in May. The sun’s late spring sweep of the archipelago favors the most southerly windward islands with earliest occurrences of Lahaina Noon before the most northerly windward islands.

Favoritism reverses in mid-summer. The archipelago’s second set of Lahaina Noons takes place in July. Mid-summer’s Lahaina Noon occurs earlier in the most northerly windward islands and later in the most southerly windward islands.

Nihoa is the only leeward island in the uninhabited Northwestern Hawaiian Islands’ (NWHI) stretch of 10 islands and atolls that undergoes Lahaina Noon. Its location, at 23.060556 degrees north latitude, falls within Earth’s equator-straddling tropical zone.

Nihoa is about 30 nautical miles (approximately 56 kilometers) closer to Kaua’i, northernmost of the archipelago’s windward islands, than to Necker Island, Nihoa’s leeward neighbor. Nihoa is approximately 130 nautical miles (about 240 kilometers) northwest of Kaua’i. Necker Island lies approximately 160 nautical miles (about 296 kilometers) northwest of Nihoa.

Necker Island’s placement at 23.576389 degrees north latitude disqualifies the hook-shaped island from the Lahaina Noon experience. The Northern Hemisphere’s Tropic of Cancer, at 23.4369 degrees latitude, and the Southern Hemisphere’s Tropic of Capricorn, at 23.4369 degrees south latitude, delimit Earth’s tropical band.

Before 900 C.E., Necker Island fell within the tropical zone, with the Tropic of Cancer lying just north. The Tropic of Cancer’s southward drift has excluded Necker Island from the Hawaiian archipelago’s Lahaina Noon experience.

The Tropic of Cancer’s southward drift toward the equator in the Northern Hemisphere mirrors the northward drift of its Southern Hemisphere counterpart, the Tropic of Capricorn, toward the equator. The equatorward drift of the two tropical extremes reflects the slowly decreasing obliquity of the ecliptic. The astronomical term references the equator’s angle of inclination with respect to the plane of Earth’s orbit, known as the ecliptic.

The takeaway for the second 2018 shadowless Lahaina Noon is that July’s solar phenomenon marks the Hawaiian archipelago’s uniqueness as the only U.S. location where the sun appears directly overhead.

Nihoa, only leeward island in the Hawaiian archipelago experiencing Lahaina Noon: Lieutenant Elizabeth Crapo, NOAA Corps, Public Domain, via NOAA Photo Library

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

SS&TC @ShortSleeveClub via Twitter June 1, 2018, @ https://twitter.com/ShortSleeveClub/status/1002608373752303616

Nihoa, only leeward island in the Hawaiian archipelago experiencing Lahaina Noon; Image ID sanc1482, NOAA's Sanctuaries Collection: Lieutenant Elizabeth Crapo, NOAA Corps, Public Domain, via NOAA Photo Library @ http://www.photolib.noaa.gov/htmls/sanc1482.htm

For further information:

“2018 Lahaina Noon Days and Times.” Bernice Pauahi Bishop Museum > 2018 Astronomy Highlights.
Available @ https://www.bishopmuseum.org/2018-astronomy-highlights/

Bryan, E.H. (Edwin Horace), Jr.; Richard Crowe; and Timothy F. Slater. Stars Over Hawaii. Third revised edition. Hilo HI: Petroglyph Press, 2015.

Marriner, Derdriu. “2016’s First Lahaina Noon Is May 15; Next 2016 Lahaina Noon Is July 11.” Earth and Space News. Wednesday, May 11, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/05/2016s-first-lahaina-noon-is-may-15-next.html

Marriner, Derdriu. “Hilo Welcomes First 2017 Lahaina Noon Thursday, May 18.” Earth and Space News. Wednesday, May 10, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/05/hilo-welcomes-first-2017-lahaina-noon.html

Marriner, Derdriu. "Hilo Welcomes Second 2017 Lahaina Noon, Monday, July 24." Earth and Space News. Wednesday, July 12, 2018.
Available @ https://earth-and-space-news.blogspot.com/2017/07/hilo-welcomes-second-2017-lahaina-noon.html

Marriner, Derdriu. "No Shadows Are Cast During May 2018 Lahaina Noon in Hawaiian Islands." Earth and Space News. Wednesday, May 16, 2018.
Availble @ https://earth-and-space-news.blogspot.com/2018/05/no-shadows-are-cast-during-may-2018.html

Marriner, Derdriu. "Second 2016 Lahaina Noon Begins Monday, July 11." Earth and Space News. Wednesday, July 6, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/07/second-2016-lahaina-noon-experience.html

“Necker Island.” What-When-How > Ancient Astronomy.
Available @ http://what-when-how.com/ancient-astronomy/necker-island/

Ruggles, Clive. Ancient Astronomy: An Encyclopedia of Cosmologies and Myths. Santa Barbara, CA: Denver, CO; Oxford, England: ABC-CLIO, Inc., 2005.

SS&TC @ShortSleeveClub. Jun 1 “Twice every year, in the US state of Hawaii, shadows completely disappear.” Twitter. June 1, 2018.
Available @ https://twitter.com/ShortSleeveClub/status/1002608373752303616

Vsauce @tweetsauce. “The Sky Gate sculpture in Honolulu, HI is wavy, but twice a year (during Lahaina noon in May and July) the sun is directly above and the sculpture's shadow is a perfect circle.” Twitter. Dec. 20, 2017.
Available @ https://twitter.com/tweetsauce/status/943615594837843968