Abrister-AST201-Lab9

NAME & USERNAME: ALEXANDRA BRISTER SECTION: 011 LAB9-1 LAB 9 POLYNESIAN WAYFINDING, I INTRODUCTION In this lab, we will explore the tools and techniques taught and used by the Polynesian Voyaging Society on traditional canoeing voyages. These techniques were developed during the 1970s and 80s, when wayfinding underwent a revival with the purpose of preserving cultural knowledge and reviving voyaging traditions in Polynesia. As the Polynesian Voyaging Society explains: “ Hōkūleʻa, our Star of Gladness, began as a dream of reviving the legacy of exploration, courage, and ingenuity that brought the first Polynesians to the archipelago of Hawai’i . The canoes that brought the first Hawaiians to their island home had disappeared from earth... On that first voyage, we were facing cultural extinction. There was no navigator from our culture left. The Voyaging Society looked beyond Polynesia to find a traditional navigator to guide Hōkūle ‘ a: Mau Piailug, a navigator from a small island called Satawal, in Micronesia. He agreed to come to Hawa i’i and guide Hōkūle ‘ a to Tahiti.” — Polynesian Voyaging Society 1 Many of the techniques explored in this lab were developed by Mau Piailug ’ s student, Nainoa Thompson. Much of the knowledge below was also taught to us by Chad Kālepa Baybayan, Hōkūle ‘ a captain and navigator in residence at the ‘ Imiloa Astronomy Center of Hawai ’ i. Sadly, in April 2021, during the creation of this lab, Kālepa passed away. We wish to take this space to honor his legacy as a navigator and educator. Without his expertise and willingness to share his expertise in traditional navigational techniques, this lab would not exist. 2 LEARNING GOALS The points below are the expected topics to understand by the end of this lab period. Remember to review these points before completing the lab. If you do not understand one, review the steps that cover it and discuss with your instructor. • Identify three examples of determining latitude using wayfinding techniques We will be making use of the Stellarium Web ( stellarium-web.org , recall Lab 1). In the following, all instructions are based on Stellarium Web. You can also choose to download and install Stellarium. For most platforms, Stellarium is free to download, but if you have trouble accessing the software, Stellarium is installed on the computers in the computer lab as well — ask your instructor for more help. Note that the setup and buttons are different from the Web version. You will continue to learn more about Polynesian Wayfinding in the next lab, Lab 10. 1 Polynesian Voyaging Society’s website is at www.hokulea.com/voyages/our-story/. 2 See In memoriam: Chad K ālepa Baybayan from University of Hawaii news at www.hawaii.edu/news/2021/04/09/in-memoriam-chad-kalepa-baybayan/.

NAME & USERNAME: ALEXANDRA BRISTER SECTION: 011 LAB9-2 STEP 1: MERIDIAN CROSSING OF A STAR We have seen from the lecture that in the Northern Hemisphere, latitude can be measured by measuring the elevation of the North Star, Polaris. This is possible because Polaris is located almost at the North Celestial Pole. However, no such bright “ South Star” exists at the Southern Celestial Pole. How does a Polynesian Wayfinder determine their latitude in the Southern Hemisphere, where Polaris is not visible? One method is to determine the altitude of a star when it crosses the meridian , the point at which it is highest overhead. “ At the Equator, the visible horizon is parallel to the earth's axis and so Polaris appears to rest on the ocean's surface. At one- degree north latitude, Polaris will conveniently rise a single degree above the horizon. What is true for Polaris is true for all the rest. Moving north, every northern star rises and every southern star sinks exactly one degree for each degree of latitude change. Move south and the northern stars sink while the southern stars rise. Unlike Polaris, these stars move, however, so their altitude must be measured when they cross the meridian — the highest point in their arc. When observed from the Equator, Acrux crosses the meridian at 27 degrees. Move north one degree and Acrux's highest rising is 26 degrees. So, if you know the meridian altitude of any star at the Equator — simple math allows you to find your latitude anywhere on earth. Each star tells a different story, so Nainoa has memorized the paths of hundreds.”— from Star Navigation by Sam Lowe for Soundings Magazine 3 Using the above description of Nainoa Thompson ’ s Meridian Crossing technique, discuss with your classmates and answer the following questions (before you open up Stellarium): 1. Is Acrux (one of the stars in Southern Cross) visible from Flagstaff (~35°N)? If so, what it its highest rising? If not, why is it not visible from Flagstaff? [0.5pt] Acrux is not visible from Flagstaff (~35 °N) because it is a star of the southern hemisphere and does not rise above the northern horizon at the latitude. Acrux's highest rising is at 27 degrees 2. What is the highest northern latitude that Acrux is visible from? [0.5pt] The highest northern latitude from which Acrux is visible would be at the Equator (0 latitude) or near it because, as mentioned, it crosses the meridian at 27 ° when observed from the Equator. 3. What is Acrux ’ s highest rising in degrees as seen from Hilo, Hawai ’ i (~20°N)? [0.5pt] Acrux ’ s highest rising in degrees, as seen from Hilo, Hawaii (~20 °N), would be 27-20= 7 degrees 4. What is Acrux ’ s highest rising in degrees as seen from Tahiti? (~18°S)? [0.5pt] Acrux ’ s highest rising in degrees, as seen from Tahiti (~18°S), would be 45 degrees 5. The brightest star in the sky, Sirius, crosses the meridian at 73° as observed from the Equator. What is Sirius ’ s highest rising in degrees as seen from Flagstaff (~35°N), Hilo (~20°N), and Tahiti (~18°S)? [0.5pt] From Flagstaff (~35°N), Sirius ’ s highest rising would be 73-35=38° From Hilo (~20°N), Sirius ’ s highest rising would be 73-20=53° From Tahiti (~18°S), Sirius ’ s highest rising would be 73+18=91° STEP 2: SIMULTANEOUS SETTING OF A PAIR OF STARS 3 The full article can be found at www.samlow.com/sail-nav/starnavigation.htm.

NAME & USERNAME: ALEXANDRA BRISTER SECTION: 011 LAB9-4 STEP 3: MERIDIAN PAIRS OF STARS A third technique that Nainoa Thompson uses is Meridian Pairs . An example of this technique was given in the lecture: when the pointer stars of the Southern Cross are at the Meridian, the distance between the two stars is equal to the distance between the lower star and the horizon at exactly at the location of 21°N on Earth (about the latitude of Hawai ’ i). “ Watching the Southern Cross arc to its meridian at the latitude of Hawaii, Nainoa noticed that the distance between the top star (Gacrux) and the bottom star (Acrux) was exactly equal to the distance between Acrux and the horizon. Thinking about this a little more, he realized that whenever an observer sees this equal spacing, he will be at 21 degrees north.”— from Star Navigation by Sam Lowe for Soundings Magazine Now set the date to July 15 th , your current year . Set your location to Hawaii (about 21°N) and look towards the Northern horizon. Zoom out your Field Of View to about 80° and locate the stars Pherkad (part of Ursa Minor) and Edasich (part of Draco) . You can use search the stars if you can't find them. Slide the time bar to find the stars at their highest rising, which should be about 23:15 Flagstaff time. In the following table, you will compare the distance from Pherkad and Edasich and the distance between Pherkad and the horizon, at different locations on Earth when they are transiting the meridian. Notice how the distances of the pairs of stars change as we move towards the equator and to the Southern Hemisphere. Fill in either greater than (>), equal to (=), or less than (<) in the table below. [6pt] Hawai ’ ian Islands (21 ° N) The distance from Pherkad and Edasich < the distance between Pherkad and the horizon Marshall Islands (7 ° N) The distance from Pherkad and Edasich < the distance between Pherkad and the horizon Nauru (0.5 ° N) The distance from Pherkad and Edasich = the distance between Pherkad and the horizon Kiribati (3 ° S) The distance from Pherkad and Edasich = the distance between Pherkad and the horizon Tokelau (9 ° S) The distance from Pherkad and Edasich > the distance between Pherkad and the horizon Samoa (13 ° S) The distance from Pherkad and Edasich > the distance between Pherkad and the horizon