chuck_final_project

Rotation: |

The Astrolabe took 3.5 hours to print and used 56 grams of material.

1. Polynesian and European strategies

One of the greatest challenges ever faced by mankind was the exploration of the Pacific Ocean. The fact that nearly all of its major features were known before even rudimentary

2. 16th century astrolabe

(by modern standards) navigation tools were developed, is a testament to the audacity of the early explorers.

Two separate strategies evolved for position finding in the great expanse of the ocean basin. The Polynesians used an oral tradition to communicate their knowledge of navigation; a tradition that relied heavily on memorization. The Europeans on the other hand, relied on tools, procedures, and algorithms to accomplish the same goals. It is the navigation tools developed in the western

3. Measuring an angle

world that I am most fascinated with. These tools are the immediate precursors to the navigation tools that I have used.

Developed in the middle ages, the astrolabe is used to measure angles. Because it was used before the advent of chronometers, it could only determine latitude. To do so required a sight to be taken of either Polaris or the Sun, each of which has a known latitude. With only a little arithmetic, the observers latitude can be

4. Print in progress

determined. My Blue Rabbit project is to use a 3D printer to  create an astrolabe. In effect, I will use a very modern technology to create a tool from the middle ages that can solve problems in today’s world. As a test of my craftsmanship and understanding, I will use the astrolabe to determine the height of the clock tower on campus.

5. Design software

6. Early failures

1. http://www.gizmag.com/freshwater-reserves-under-sea/30072/,   http://www.gearthblog.com/blog/archives/2011/11  /captain_james_cooks_circumnavigatio.html, http://sixboats.co.nz/wakas-part-3/

2. http://kids.britannica.com/comptons/art-150173/A-Portuguese-bronze-astrolabe-dates-to-1555

3. http://commons.wikimedia.org/wiki/File:Astrolabe_(PSF).png

Chuck Neudorf
Iteration #2
WD CT 1000:1500

What I propose to do for my Blue Rabbit project is to blur the temporal aspect of technology. I hope to use new technology to create an old tool that can solve problems in today’s world that were first solved long ago. Further, I hope that the use of this tool will foster an understanding of how the world works. Additionally, I would like to look at how tools extend the mind of the user.

The tool I am making is a plumb bob sextant, a precursor to the marine sextant. It is a simple tool that measures angles above the horizontal plane using a plumb bob as a vertical reference. It is a simple, yet remarkable tool. It can be used to determine the height of a building or a mountain. It can also measure the height of a celestial body above the horizon to determine latitude. Before the early eighteenth century, this was as good as navigation tools got. That is, most of the Earth was explored with tools no more accurate then the plumb bob sextant.

I am a navigator. I have had the responsibility of finding a path across an ocean, without electronic aids to navigation. The tools I used were more sophisticated than those that I have 3D printed, but the principles are the same. Using the tools and the algorithms of navigation is one of the most interesting and rewarding things I have done.

While it is called a plumb bob sextant, the device I have made is actually an astrolabe. The difference is that a sextant measures an angle relative to the horizon where an astrolabe measures an angle relative to a vertical line established by gravity. Neither instrument is more inherently accurate than the other, but because of ease of use, the sextant can generally produce more accurate results.

There are records of astrolabes as early as 150 BC, but it wasn’t until advances in sail configuration, hull design, and magnetic compasses that navigators had the tools necessary to explore the planet. Instructions for the use of the astrolabe came from some notable sources. “The simplest and most available English work on the description and use of the astrolabe is the “Tractatus Conclusionibus Astrolabii” written be Geoffrey Chaucer in 1391 and 1392.” (Latham). Historically, mariners had to stay within sight of land, but once the tools were in place, that changed. “The application of the astrolabe, and the abandoning of the time-honored route of exploration, along the African coast, for steering a bold course westward in pursuit of Cathay and fabled lands as yet unexplored, resulted in the addition of a continent in the greatness and progress of which the Old World, while admitting a sister in the family of nations in the present is already looking for a rival in intelligence wealth and progress.” (Journal of the American Geographical Society of New York). The ability to sail out of sight of land for weeks at a time, and yet still know ones position, led to the great voyages of discovery of the 14th through 16th centuries. Early in the 18th century, two inventions made marine navigation easier and more accurate. The sextant and chronometer together, allowed longitude to be calculated, where before it was estimated. While a reasonable replica of a sextant can be made with a 3D printer, the chronometer is out of the question. Consequently, I’m drawing the line in the sand of technology at the early 18th century.

For navigation purposes, an astrolabe works by measuring the angle of a celestial body above the horizon. There are only two targets we are interested in, Polaris (the North Star), and the sun. Given a few constraints, if we measure the height of either of these bodies, we can determine our latitude. The number we get from the astrolabe is not a direct reading so we’ll have to do some calculations. Don’t worry, nothing more than some addition and/or subtraction. One of the great things about this system is that it requires you to understand some of the basic facts of the solar system. You have to understand that Polaris is directly over the North Pole. You have to understand how the suns path changes throughout the day, what defines the tropics and the seasons, and even which way the Earth spins. You really get to know your home planet.

Our discussion so far has been Eurocentric, but the exploits of the Polynesian navigators were every bit as impressive. They used different navigation concepts and very different boats. Where Europeans plotted the advancing position of their vessel on a static chart, the Polynesians saw themselves as being at the center while the stars and islands and other navigational clues were in motion around them. The European strategy was to formalize the tools and teachings of navigation while the Polynesians relied on an oral tradition. Between the two cultures, there was a large difference in opinion as to what constituted a proper ship. “To the European mind the only seaworthy vessel is one made buoyant by a watertight air-filled hull, so big and high that it cannot be filled by the waves. To the ancient Peruvians the size was of less importance; the only seaworthy craft was one which could never be filled by water because its open construction formed no receptacle to retain the invading seas, which washed through.” (Heyerdahl)

The Polynesians were able to not only explore but to colonize the vast expanse of the Pacific basin before the Europeans even saw the Pacific. “We could trace the introduction of these Amerindian alleles to before the Peruvian slave trades, i.e. before the 1860s, and provide suggestive evidence that they were introduced already in prehistoric time. Our results demonstrate an early Amerindian contribution to the Polynesian gene pool on Easter Island, and illustrate the usefulness of typing for immunogenic markers such as HLA to complement mt DNA and Y chromosome analyses in anthropological investigations.” The extent of Polynesian influence reached all the way to the Americas.

It is easy to see how the two cultures differed in their approaches to navigation. My attention now turns not to the similarities of mechanics but to the similarities of being. How do you set off on a voyage of exploration? What lessons are learned when travelling on the open sea? “For scientists studying how humans come to understand their world, the central challenge is this: How do your minds get so much from so little: We build rich causal models, make strong generalizations, and construct powerful abstractions, whereas the input data are sparse, noisy and ambiguous-in every way far too limited. A massive mismatch looms between the information coming in through our senses and the outputs of cognition.” (Tenenbaum)

What of the mind of the navigator? If the Polynesian and the European reach the same goals but use different tools, are the respective tools responsible for the same or different extensions of the mind. How does time affect these questions? When I sailed down the trades to Hawaii thirty years ago, how connected was my mind to Jack London’s who had sailed the same route 100 years ago; or with George Vancouver who sailed the route 100 years before him? It is said that the measure of a navigator is his demeanor when he has no idea of where he is. That is something, I believe, we all share.

My project starts with things that I am comfortable and familiar with. Soon enough, I find myself with lots of questions and few answers. I don’t really even have a strategy for finding some of these answers. It’s okay. I’m a navigator; I’ll just keep forging ahead and not let anyone know that I’m lost. No sense in all of us being panicked.

The Astrolabe
Marcia Latham
The American Mathematical Monthly, Vol. 24, No. 4 (Apr., 1917), pp. 162-168
Published by: Mathematical Association of America
Article DOI: 10.2307/2973089

Transactions of the Society for 1872
Journal of the American Geographical Society of New York
Vol. 4, (1873) , pp. 35-56
Published by: American Geographical Society

The Balsa Raft in Aboriginal Navigation off Peru and Ecuador
Thor Heyerdahl
Southwestern Journal of Anthropology, Vol. 11, No. 3 (Autumn, 1955), pp. 251-264
Published by: University of New Mexico
Article Stable URL: http://www.jstor.org/stable/3629024

The Polynesian gene pool: an early contribution by Amerindians to Easter Island
Erik Thorsby
Philosophical Transactions: Biological Sciences, Vol. 367, No. 1590, Immunity, infection, migration and human evolution (19 March 2012), pp. 812-819
Published by: The Royal Society
Article Stable URL: http://www.jstor.org/stable/41441734

How to Grow a Mind: Statistics, Structure, and Abstraction
Joshua B. Tenenbaum, Charles Kemp, Thomas L. Griffiths and Noah D. Goodman
Science, New Series, Vol. 331, No. 6022 (11 March 2011), pp. 1279-1285
Published by: American Association for the Advancement of Science
Article Stable URL: http://www.jstor.org/stable/41075877

Chuck Neudorf
20 October 2014
Blue Rabbit
Iteration #1

I would not be satisfied making trinkets with a 3D printer for my Blue Rabbit Project. There were several false starts while trying to decide what to make, but when I hit on the idea of making something that is functional and that might also work as a teaching aid, I knew I was on the right track. Because I have a background in navigation, it seemed logical to go in that direction. To choose which device to make was a matter of eliminating the impossible ones and then see what’s left.
The first to go were the electronic devices. GPS receivers are small and superbly accurate but far to complex for 3D printing. I could probably make a cover for my GPS unit, but that doesn’t seem like a proper challenge, nor does it provide a teaching opportunity.
Before there was electronic navigation, there was celestial navigation. Tools were used to measure the angular distance of celestial bodies above the horizon. That measurement, along with accurate time and either tabular data or formulas, allowed navigators to determine their position. Foremost among these tools is the sextant. Traditionally made of metal, there are some sextants available in plastic. While we may be getting closer, sextants are still too complex for 3D printing. They have many moving parts plus gears plus optics.

The first device I actually tried to make was an astrolabe. This device is a precursor to the sextant and has far fewer parts. My design has only two parts, a base and a sighting ring. One of the issues I have with this unit is how to read the numbers it generates and another issue is sizing the two pieces so that they don’t bind on the one hand, and they don’t lose too much accuracy on the other. At this point the astrolabe is on hold while I work on the next design, but I fully expect to return to it.

It should be noted that every time we step backward on the technology scale, we lose some accuracy, but if we have to give up accuracy in order to get a tool that works, so be it. That is the deal I am making by creating a plumb bob sextant. This is the simplest design yet and I can guarantee that it will work but I won’t have any idea about its accuracy until it is tested. This device is simply a 3D printed plane with angular values marked at 10-degree increments. A weighted string is attached so that when the upper edge of the tool is angled above horizontal, the angular value of the rotation can be read where the string intersects the scale. (Burch, 149.).

Assuming we can use these tools to measure how high in the sky the sun is (as an example), what can we hope to learn? The sun appears to rise in the sky throughout the morning, stops at its highest point for just an instant, and then begins its descent. The point where the sun appears to stop is very special to a navigator, that is the point when the sun is exactly on the same meridian of longitude as the observer. At that point, latitude can be calculated with just a little addition and subtraction. (Bowditch. 344.) The practical aspect of using these tools is being able to tell where you are. The slightly less practical but equally important aspect is that by looking closely enough at the world around us, we can understand how it works.

Of course, not every seafaring culture has a use for the tools that are so familiar to me. Hundreds of years before Europeans found their way to the Pacific Ocean, Micronesian navigators explored the entire Pacific basin. “Micronesian navigation, I realized, is also an integrated system; instead of being based on charts and instruments, it relies on a vast body of lore and the navigators own senses”. (Thomas. 75.) The test of the Polynesian navigators was their ability to find low-lying islands that are far away. Fortunately for me, my challenge won’t be that difficult.
The tools that I am building will measure angles, and they’ll work fine on targets other than the sun, moon, and stars. I propose that a fair test of the design and execution of my tools (and my math), will be to use them to determine the height of the clock tower on campus.

Bowditch, Nathaniel. The Marine Sextant: Selected from American Practical Navigator. New York: D. McKay, 1976. Print.
Burch, David. Emergency Navigation. Camden, Me.: International Marine Pub., 1986. Print.
Thomas, Stephen D. The Last Navigator. New York: H. Holt, 1987. Print.