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Celestial navigation - still worth studying?
- Thread starter bae
- Start date
- Joined
- Oct 1, 2000
- Messages
- 175
Brothers & Sisters of Finding Our Way,
Some time ago my flight arrived in Honolulu. As we were de-planing three Naval Officers stood to make their way forward toward the hatch. "Gentlemen" I asked, "Doesn't it seem to be presumptuous to arrive at one of the largest ports in the world by air?"
They looked at each other as if to say "The man has a point."
There are 88 constellations and a go-zillion waypoints. The constellations have been there since the first sailor set to sea. GPS? A passing fad!
What's the quote "And all I ask is a tall ship and a star to sail her by..." (Sea Fever by Sir John Masefield)
How quickly they forget.
Regards,
Lance Gothic
Shibumi
Some time ago my flight arrived in Honolulu. As we were de-planing three Naval Officers stood to make their way forward toward the hatch. "Gentlemen" I asked, "Doesn't it seem to be presumptuous to arrive at one of the largest ports in the world by air?"
They looked at each other as if to say "The man has a point."
There are 88 constellations and a go-zillion waypoints. The constellations have been there since the first sailor set to sea. GPS? A passing fad!
What's the quote "And all I ask is a tall ship and a star to sail her by..." (Sea Fever by Sir John Masefield)
How quickly they forget.
Regards,
Lance Gothic
Shibumi
I just taught the Astronomy merit badge to my scout troop. It includes techniques for determining your latitute (takes two days to do ...)
Considering what can be done with a compass and good map on land, I don't think it has much use here. On the sea, it could be a different matter. For the purposes you have described elsewhere for your boating, I don't think it's worth it. Short of primitive trans-oceanic voyages, there are other simpler methods for shorter trips.
As has been pointed out, basic knowledge of the sky and dead reckoning is always a useful skill, but it's fraught with it's own problems.
I highly recommend the PBS Nova special on Longitude as well as the cable movie. Using the sextans? to measure the sun on a wave motion deck is very difficult for good accuracy of Latitude. Longitude, short of today's great watches (or comparable historical pieces) is a nightmare. And then you're back to batteries anyway.
Phil
Considering what can be done with a compass and good map on land, I don't think it has much use here. On the sea, it could be a different matter. For the purposes you have described elsewhere for your boating, I don't think it's worth it. Short of primitive trans-oceanic voyages, there are other simpler methods for shorter trips.
As has been pointed out, basic knowledge of the sky and dead reckoning is always a useful skill, but it's fraught with it's own problems.
I highly recommend the PBS Nova special on Longitude as well as the cable movie. Using the sextans? to measure the sun on a wave motion deck is very difficult for good accuracy of Latitude. Longitude, short of today's great watches (or comparable historical pieces) is a nightmare. And then you're back to batteries anyway.
Phil
Good thread...
IMHO The GPS system is a great addition to our navigation capabilities but a knowledge of celestial navigation is critical to more than just locating your position on the planet. It gives a sense of connection to the great clock of our Universe and enables us to tell time to within a few minutes, tell direction and latitude in short order. It gives us an understanding of the harmony of nature and the methodologies the ancient ones had for navigation, hunting and crop planting cycles.
As an aside... Latitude is the "ladder up the Earth" and Longitude is the "long way around". To specify the latitude of some point on the surface, draw the radius to that point. Then the elevation angle of that point above the equator is its latitude. Northern latitude if north of the equator, Southern (or negative) latitude if south of it.
To determine your Latitude at any time simply Identify the North Star (polaris) and measure the angle to it as measured from "level" at your location. i.e. If the angle to the North Star is 45 degrees you are at 45 degrees North Latitude. At the North Pole the North star is at 90 degrees (vertical) to your position.
The Longitude requires more time and effort but can be accomplished with string and an approximation of your date. Time can be determined easily if you know the date. In volume 10 of our video series we go through the system and from that you can determine time. Using the time you deterimine from the stars the displacement of star positions. After a few days you can work forward to your Longitude. Is this valuable? Probably not unless it is an intellectual exercise. Fun because it helps you to relate to the globe and the heavens but pretty useless as a position indicator for search aircraft.
Ron
IMHO The GPS system is a great addition to our navigation capabilities but a knowledge of celestial navigation is critical to more than just locating your position on the planet. It gives a sense of connection to the great clock of our Universe and enables us to tell time to within a few minutes, tell direction and latitude in short order. It gives us an understanding of the harmony of nature and the methodologies the ancient ones had for navigation, hunting and crop planting cycles.
As an aside... Latitude is the "ladder up the Earth" and Longitude is the "long way around". To specify the latitude of some point on the surface, draw the radius to that point. Then the elevation angle of that point above the equator is its latitude. Northern latitude if north of the equator, Southern (or negative) latitude if south of it.
To determine your Latitude at any time simply Identify the North Star (polaris) and measure the angle to it as measured from "level" at your location. i.e. If the angle to the North Star is 45 degrees you are at 45 degrees North Latitude. At the North Pole the North star is at 90 degrees (vertical) to your position.
The Longitude requires more time and effort but can be accomplished with string and an approximation of your date. Time can be determined easily if you know the date. In volume 10 of our video series we go through the system and from that you can determine time. Using the time you deterimine from the stars the displacement of star positions. After a few days you can work forward to your Longitude. Is this valuable? Probably not unless it is an intellectual exercise. Fun because it helps you to relate to the globe and the heavens but pretty useless as a position indicator for search aircraft.
Ron
- Joined
- Nov 21, 2001
- Messages
- 848
Well, I spend most of my time in the Salish Sea (the Strait of Georgia, Puget Sound and the Strait of Juan de Fuca), and the Inside Passage. Taking sights here is a bit troublesome, due to the cloud cover and mountain ranges on the horizon. Still, I find the sextant handy, if only for measuring angles between points on land. I've fabricated some simpler, more primitive predecessors of the sextant for this task.
I'm working up to some open-ocean voyaging, but am hoping to use traditional Polynesian navigational techniques, keeping the celestial (and a bag-o-GPS's) as a backup. Unfortunately, this will require me to spend a great deal of time in Hawaii educating myself on the subject. What a shame
For your boat work can I suggest the ancient Egyptian Theodolyte design? It is based on three posts set in a board with a crosshatch pattern. I ran across it in Cairo years ago. The user needs to only know the date and at noon looks at the shadows cast by the three posts. The position of the three shadows works to a graph that gives your location on the globe. I remember that the archaeologists had worked out a conversion to the Lon/Lat we use today. Large for backpacking but good on the deck of a boat in calm seas.
I'll look for some references....
Ron
I'll look for some references....
Ron
Hey Bae...
Here is one reference that might be amusing... I set this one up and it gave me a fairly accurate estimation. The specific device I am thinking of used the plumb lines and posts but so far no luck finding it....
http://www.egyptmonth.com/mag03012001/magf7.htm
There are so many cool tricks the ancients used.... just wood, weights and constants.
Ron
Here is one reference that might be amusing... I set this one up and it gave me a fairly accurate estimation. The specific device I am thinking of used the plumb lines and posts but so far no luck finding it....
http://www.egyptmonth.com/mag03012001/magf7.htm
There are so many cool tricks the ancients used.... just wood, weights and constants.
Ron