On Wed, Jul 21, 2010 at 7:01 PM, MATT MARINER BROZE <marinerkayaks_at_msn.com>wrote: > > My point is that the native paddlers may do it the way they do because > that is what someone in a position of influence thought (and their > ideas remained dominant long after they were dead) and the few who... What we have here is the stupid natives syndrome. In the book "Longitude" that I mentioned the other day, the European sailors that first found their way to the Pacific islands considered the "NATIVES" to be uneducated primitives. The hotshot Europeans at the time could not tell how far around the globe they were. At a time when the Europeans had no answer, the Pacific navigators new latitude by the north star and by the position of other stars at their zenith. They knew the stars that marked true east and west and they knew which islands were located along which latitudes. For a thousand or more years before Europeans invented clocks, the natives were the masters of navigation in the pacific and the Europeans were the primitives-by far too primitive to listen to anything the native mariners had to say. Remarkable that anyone would have the attitude that arctic hunters were using long paddles because they were too stupid to use short ones. I agree that in these matters, there seems to be a serious ego barrier involved. Chuck Sutherland *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
skimmer wrote: > On Wed, Jul 21, 2010 at 7:01 PM, MATT MARINER BROZE > > <marinerkayaks_at_msn.com>wrote: >> My point is that the native paddlers may do it the way they do because >> that is what someone in a position of influence thought (and their >> ideas remained dominant long after they were dead) and the few who... > What we have here is the stupid natives syndrome. > In the book "Longitude" that I mentioned the other day, the European sailors > that first found their way to the Pacific islands considered the "NATIVES" > to be uneducated primitives. The hotshot Europeans at the time could not > tell how far around the globe they were. At a time when the Europeans had no > answer, the Pacific navigators new latitude by the north star and by the > position of other stars at their zenith. They knew the stars that marked > true east and west and they knew which islands were located along which > latitudes. For a thousand or more years before Europeans invented clocks, > the natives were the masters of navigation in the pacific and the Europeans > were the primitives-by far too primitive to listen to anything the native > mariners had to say. > Remarkable that anyone would have the attitude that arctic hunters were > using long paddles because they were too stupid to use short ones. I agree > that in these matters, there seems to be a serious ego barrier involved. Chuck, Your point about the possible efficacy of long paddles has been made, made, and made. To resort to distortion and exaggeration, not to mention a veiled accusation of racism, to debate the length of paddle we might use is outrageous. You can quit now. I doubt anybody is listening to this sort of "argument." On the other hand, I'd listen to discussions of the merit of paddle length if they were substantive. Let's do that for a while, OK? -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
skimmer wrote: > On Wed, Jul 21, 2010 at 7:01 PM, MATT MARINER BROZE > > <marinerkayaks_at_msn.com>wrote: >> My point is that the native paddlers may do it the way they do because >> that is what someone in a position of influence thought (and their >> ideas remained dominant long after they were dead) and the few who... > What we have here is the stupid natives syndrome. On the contrary, I have nothing but respect for native peoples, but I'm not going to put them on a pedestal either. Let's be realistic, we know we, as a society, have suffered from many delusions in the past, and are most likely still suffering from many we don't even realize exist yet (if we ever will). How many years was it that people believed Aristotle's proclamation that heavier objects fall faster than lighter ones? To assume that native peoples had reached perfection and don't suffer from some of the same sources of human error as we do is just not being realistic. Assuming natives had reached paddle optimization is likely as much of an error as assuming they were not just as sophisticated as we are, but just look at things differently than we do, and do things for reasons that we don't understand. I read "We the Navigators" back in the 1980's. Long before that I tried learning native techniques for how to survive living in the wilderness. Let me tell you, if you try, that you will realize how many skills they had that we have lost. Ever try to get a fire going using a friction method? I'm pretty good at figuring things out, I made a lot of smoke, a few hot embers even, but although I got much better with practice, and improved my tools by reading and experimenting, and worked at it diligently for about a month, I never did turn that knowledge into an actual campfire. You are definitely wrong on this assumption I think natives were stupid. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On Jul 22, 2010, at 1:11 PM, skimmer wrote: > The hotshot Europeans at the time could not > tell how far around the globe they were. Knowing how far around the globe you are is longitude not latitude. This required a very accurate clock which was technically hard to achieve. The Pacific navigators had no way of determining longitude from the stars > At a time when the Europeans had no > answer, the Pacific navigators new latitude by the north star and by > the > position of other stars at their zenith. The Europeans knew their latitude just fine *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On Tue, Jul 27, 2010 at 9:59 AM, Robert Livingston <bearboat2_at_comcast.net>wrote: > > > The Pacific navigators had no way of determining longitude from the stars > True. But Chuck specifically said that they could determine true east and west from the stars. My gut reaction to this was "BS" but upon thinking it over I believe that knowing the BAND of stars that ring the equator could give them clues to true east and true west (independently of the sun). Of course, keeping Polaris to your starboard or port would also work; as long as you were far enough above the equator to see Polaris. I suspect the Pacific Navigators did the same thing as the European Navigators; sailed to a latitude well east (or west) of their destination and turned the proper direction. There is even a name for this: "running down the latitude". Craig Jungers Moses Lake, WA www.nwkayaking.net *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Craig wrote............ True. But Chuck specifically said that they could determine true east and west from the stars. My gut reaction to this was "BS" but upon thinking it over I believe that knowing the BAND of stars that ring the equator could give them clues to true east and true west (independently of the sun). Of course, keeping Polaris to your starboard or port would also work; as long as you were far enough above the equator to see Polaris............ G'day Craig, The book "Longitude" centres around a dispute between the Astronomer Royal and the clockmaker Harrison, about the relative merits of clocks vs. a very protracted and complicated calculation based on star measurements that was in vogue at the time. Its an engrossing read, as good as any political thriller and not at all dry. Recommend the illustrated version to anyone who hasn't read it. Or the BBC TV series. I've often wondered just how the astronomers did their calculation and it sounds as if you have insight into how this might have worked. I'd be glad of any suggestions you might have for understanding the method better? All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
P.S. I guess that if the position and movement of stars could be analysed by European seamen trigonometrically, to produce a value for longitude and determine a position around the earths axis; then that pattern of stars could be analysed by a Pacific Islander's brain or a computer to find that position without resorting to trigonometry or the concept of longitude. Nowadays we'd call it something like a neural network analysis, or pattern recognition program or some such! However, maybe it wasn't just the stars. I remember once paddling about 17km out to sea from Newcastle (Australia) with a companion and noticed that he did not carry a compass. Nevertheless he did this paddle regularly. We were out of sight of land and it was sobering to scan a featureless horizon for 360 degrees and realise I would have been lost without a compass. My companion claimed that he steered by the clouds on the horizon! I thought this was incredible, dangerous and ridiculous. I no longer think its ridiculous and can imagine that highly skilled Pacific Islanders, plying their trade in an archipelago and raised all their life to that kind of approach might be able to recognise the currents, wave patterns, and wind patterns between islands as well as using the stars and other clues to find their way around. I'm sure I've read about this somewhere and with luck knowledgeable Paddlewisers could refer me to books on the subject. In deference to the Paddlewise ethos plea se don't take it that I'm advocating anything so dangerous as an appropriate practice unless one was born to it. All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
No The problem is more fundamental. The position of the stars does not tell you the LONGITUDE whether you have a computer or a sexton or "intuition" or a neural network. It does tell you the LATITUDE. The Europeans knew their LATITUDE if they could get a clear view of the night sky. If someone tells you the LATITUDE of Hawaii and how many days of sailing west from San Francisco they could find it again (as those "hot shot" Europeans did) Local knowledge with cloud formations, how long you have been paddling, birds, wave and current information can tell you where you roughly where you are in the absence of the visibility of land assuming you "know" all the local islands etc. On a lesser scale, you have probably done the same thing in a dense fog. If you are reasonably alert to the sounds of surf, birds, waves, how long you have been paddling, you can make guess as to where you likely are. And "Australia" is a pretty big target from 17 km out just from knowing where the sun is :) On Jul 28, 2010, at 6:19 AM, rebyl_kayak_at_energysustained.com wrote: > I guess that if the position and movement of stars could be analysed > by European seamen trigonometrically, to produce a value for > longitude and determine a position around the earths axis; then that > pattern of stars could be analysed by a Pacific Islander's brain or > a computer to find that position without resorting to trigonometry > or the concept of longitude. Nowadays we'd call it something like a > neural network analysis, or pattern recognition program or some such! *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
PeterO: All the people who still think it's ridiculous are unfortunately lost at sea, and can't read their e-mail. Brad Subject: RE: [Paddlewise] Longitude and astronomy > However, maybe it wasn't just the stars. I remember once paddling about > 17km out to sea from Newcastle (Australia) with a companion and noticed > that he did not carry a compass. Nevertheless he did this paddle > regularly. We were out of sight of land and it was sobering to scan a > featureless horizon for 360 degrees and realise I would have been lost > without a compass. My companion claimed that he steered by the clouds on > the horizon! I thought this was incredible, dangerous and ridiculous. I no > longer think its ridiculous . > All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On Wed, Jul 28, 2010 at 2:15 AM, PeterO <rebyl_kayak_at_energysustained.com>wrote: > > I've often wondered just how the astronomers did their calculation and it > sounds as if you have insight into how this might have worked. I'd be glad > of any suggestions you might have for understanding the method better? > > Before we had "computers" it was a career path for mathematically inclined people who were employed by universities and scientific organizations to undertake the tedious calculations required by science experimenters. They were employed as "computers" to... well... compute. These computations often found their way into tables that were published and collected to make the math easier. Sine tables, cosine tables, log tables, etc. were all part and parcel of an engineer's or scientist's life not more than two generations ago (along with slide rules). The idea of celestial navigation revolves around the concept that a celestial body is directly above some point on the earth at some point in time. The pesky habit the earth has of rotating every 24 hours introduces some complications. So "computers" were employed to calculate the point on the earth a celestial body would be above at every second of time. When you know the time accurately you can use the navigational tables to determine the geographic location that your celestial body is directly above and then use a sextant to determine just how far away from that geographic position you happen to be using relatively simple trigonometry. (There are tables for spherical trig calculations, too.) Unfortunately the result of this procedure turns out not to be a point on the map but a circle. Much like simply taking the height of a streetlamp to determine how far you are away from its base. It tell you nothing about which direction you are away from the base but only how far. This is called, in navigational terms, a "line of position". In order to get an accurate idea of where you really are you need to 'cross" that first sighting with a second one that is, preferably, 90 degrees or so offset from it. So that the two lines of position intersect where you happen to be. If the two celestial bodies are not far enough apart you can get some significant confusion in the accuracy. This causes navigators to do what we like to call a "round of stars" and is why the second officer of a ship (traditionally the "navigational officer) has watches that make it easier to take star sights as well as a couple of sun sights. (The position using the sun is treated slightly differently from that of a star sigh.) In the old days the science and art of navigation was highly prized amongst mariners and we often collected and practiced various methods of reducing celestial sights to geographical positions. Space and weight was not a factor for ship navigators but aviators and yachtsmen discovered that 48 volumes of navigational tables were somewhat bulky. At some point in time the British Home Office (which kindly published many of these tables) came out with H.O. 249 which had a limited number of navigational stars but was only in a couple volumes. This, along with a nautical almanac, a good timepiece, and a sextant was all one would need to navigate a vessel or aircraft around the world. This, in a nutshell, is how celestial navigation works (more or less). But the actual method for calculating the data was outside my expertise. So I probably did not answer your question. But maybe answered questions others had on this subject. Craig Jungers Moses Lake, WA www.nwkayaking.net *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Craig wrote: .......48 volumes of navigational tables were somewhat bulky......... .......This, in a nutshell, is how celestial navigation works (more or less)...... Rob wrote: ........The position of the stars does not tell you the LONGITUDE....... Joe wrote: "That's not too different from the Pacific navigators who used different cues, perhaps, but over the generations had reached conclusions about their reliability and how to interpret them..." Craig, that was a wonderful description with plenty of clues to chase. I wasn't sure when you talked about needing an accurate clock whether you mean't accurate over months so as to reference back to GMT or just accurate for an hour or two to do the celestial measurements, but after following up some of the key ideas you described I'm guessing you mean't the latter. Anyway many thanks indeed, for a clear and interesting outline. Robert, You're right of course. I thought about it and went back to the books and realised I should have said the stars and the planets and their moons. Then longitude can be measured using the tables that Craig mentioned; first espoused by Newton, written by Mayer and then put into practice by Maskelyne, Harrison's arch nemesis. I believe Australia was discovered by Cook using this method. As you say its a big island. It may have been Paul Theroux who said Australia's inhabitants were under the illusion they were Pacific Islanders? Anyway that's the sort of thing I had in mind 17km off shore wondering how one would manage with a featureless horizon. Thank heavens for the bulk carriers and cigarette boat racers that brought me back to earth:~) Joe, That's pretty much what I was trying to say. Seems as if some measure of time is needed as well. But I know from market gardening in the 60's that ancient gardeners don't need clocks to tell the time, Imagine the same could be true of islanders! Thanks everyone and all the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On Thu, Jul 29, 2010 at 4:26 AM, <rebyl_kayak_at_energysustained.com> wrote: > Seems as if some measure of time is needed as well. But I know from market > gardening in the 60's that ancient gardeners don't need clocks to tell the > time, Imagine the same could be true of islanders! > The islanders certainly didn't need any clocks to determine local time; practically anyone can estimate the time by looking at the sun. But this is useless for determining longitude because all you can measure is high noon. You just don't know if it's high noon at position X or high noon at position Y. High noon comes to everyplace once every 24 hours. How would you know, absent some geographical reference, whether you were observing high noon in Boise, Idaho or high noon in Perth, Australia? This might be good enough for gardening but leave a bit to be desired should you be somewhat concerned about the reefs you might be sailing toward. Craig Jungers Moses Lake, WA www.nwkayaking.net *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> How would you know, > absent some geographical reference, whether you were observing high noon in > Boise, Idaho or high noon in Perth, Australia? > During most times of the year, the altitude of the sun at high noon would give a good clue, especially during the Perthian summer when there is up to about a 60 degree difference in the sun's noon altitude. Assuming one knows what time of year it is. The tricky times are early April and early September when the noon altitudes are similar (between Perth and Boise). And, as others have pointed out, the position of the moon also gives a clue. Thanks, Mark *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Let me suggest, as an interesting read that touches on this topic in some depth, "An Ocean in Mind" by Will Kyselka. (I'll also note that "The Last Navigator" by Steve Thomas may be equally apropos, but I haven't read the latter.) ---Rsk *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Craig: Is the answer to the last question kangaroos? Brad Subject: Re: [Paddlewise] Longitude and astronomy > On Thu, Jul 29, 2010 at 4:26 AM, <rebyl_kayak_at_energysustained.com> wrote: > >> Seems as if some measure of time is needed as well. But I know from >> market >> gardening in the 60's that ancient gardeners don't need clocks to tell >> the >> time, Imagine the same could be true of islanders! >> > > The islanders certainly didn't need any clocks to determine local time; > practically anyone can estimate the time by looking at the sun. But this > is > useless for determining longitude because all you can measure is high > noon. > You just don't know if it's high noon at position X or high noon at > position > Y. High noon comes to everyplace once every 24 hours. How would you know, > absent some geographical reference, whether you were observing high noon > in > Boise, Idaho or high noon in Perth, Australia? > Craig Jungers > Moses Lake, WA *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Brad wrote .........Craig: Is the answer to the last question kangaroos?........... Cook wrote in his journal http://southseas.nla.gov.au/journals/cook/contents.html .......... 17 April 1770 Tuesday 17th At 2 PM the wind came to WSW at which time we tack'd and stood to the NW, before 5 oClock we was obliged to close reef our topsails having a strong gale with very heavy squals, about this time a small land bird was seen to pearch upon the riging, we sounded but had no ground with 120 fathoms of line. At 8 oClock we wore and stood to the Southward until 12 at night than wore and stood to the NW untill 4 AM when we again stood to the Southd haveing a fresh ^gale at WSW attend with squals and dark hazey unsettled weather untill 9 oClock at which time it fell little wind and the weather ^soon after clear'd up which a little after a 11 gave us an oppertunity of takeing several observations of the Sun and Moon the mean result of which gave 2070..56' West Longitude from the Meridion of Greenwich, from these observations the Longitude of the Ship at Noon was 2070..58' and by the Log 2080..20' the difference being on^ly 22' and ^this error may as well lay in the one as the other, our Latitude at noon was 390..36' So and Longde made from Cape Farewell 220.22' Wt ........... G'Day, Cook didn't make any mention of kangaroos in his journal Brad:~) However, he was trained in astronomy and had astronomers with him for measuring the transit of Venus in Tahiti. I think he was also on the Board of Longitude and would have been well aware of the tables produced by Warner and Maskelyne. I was well pleased to have found his journal entry above. It looks as if Cook might have used a process such as recalibrating his clock for local time every day against sunrise, sunset and noon. The clock would then only have to remain within spec for 24 hours and not for months or years to maintain synchronism with Greenwich. Presumably there were enough stars visible in both the southern and northern hemispheres so that Cook in Australia could use the tables developed at Greenwich. Cook was within a degree of longitude when he reached the equator after surveying the east coast of Australia on his first voyage. As Robert said it was such a tricky method and judging from the above journal entry not much better than using the kind of clock that was available prior to Harrison. When Cook went on his 2nd voyage he took along a Harrison clock. Robert, Longitude is a wonderful book and the illustrated version is well worth getting, it has a great many side notes that are missing from the text only version. All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
PS Sorry I should have included the Lunar distance method as capitalised below ............It looks as if Cook might have used a process such as recalibrating his clock for local time every day against sunrise, sunset and noon. The clock would then only have to remain within spec for 24 hours AND MEASURE LOCAL TIME and not for months or years to maintain synchronism with Greenwich. Presumably there were enough stars visible in both the southern and northern hemispheres so that Cook in Australia could use the tables developed at Greenwich TO TRY OUT THE LUNAR METHOD........... All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On Fri, Jul 30, 2010 at 1:49 AM, PeterO <rebyl_kayak_at_energysustained.com>wrote: > > ............It looks as if Cook might have used a process such as > recalibrating his clock for local time every day against sunrise, sunset > and > noon. The clock would then only have to remain within spec for 24 hours AND > MEASURE LOCAL TIME and not for months or years to maintain synchronism with > Greenwich. Presumably there were enough stars visible in both the southern > and northern hemispheres so that Cook in Australia could use the tables > developed at Greenwich TO TRY OUT THE LUNAR METHOD........... > > Thinking this over, the ancient Pacific navigators could have used very much the same system using a sand-clock calibrated for 24 hours. Accuracy would not have been so great but then they would at least have had some measure of local time. Craig *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
I use a sand clock at home. Typically I arrive at work 3 days late (or is it 4 days early?). -- Bradford R. Crain Quoting Craig Jungers <crjungers_at_gmail.com>: > On Fri, Jul 30, 2010 at 1:49 AM, PeterO > <rebyl_kayak_at_energysustained.com>wrote: > >> >> ............It looks as if Cook might have used a process such as >> recalibrating his clock for local time every day against sunrise, sunset >> and >> noon. The clock would then only have to remain within spec for 24 hours AND >> MEASURE LOCAL TIME and not for months or years to maintain synchronism with >> Greenwich. Presumably there were enough stars visible in both the southern >> and northern hemispheres so that Cook in Australia could use the tables >> developed at Greenwich TO TRY OUT THE LUNAR METHOD........... >> >> Thinking this over, the ancient Pacific navigators could have used very > much the same system using a sand-clock calibrated for 24 hours. Accuracy > would not have been so great but then they would at least have had some > measure of local time. > > > Craig *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
>> The clock would then only have to remain within spec for 24 hour Not really. The only useful clock is a VERY accurate one. You cannot stay linked with Greenwich by using an inaccurate clock and "correcting" it for local time. For one thing, when you are actually moving east west, local time "noon to noon" is no longer exactly 24 hours. In fact, it is the discrepancy that you are trying to detect to see how far east west you have gone. If you are not moving, then correcting your clock every 24 hours does you no good. Part of the engineering problem was creating a clock that remained accurate under the varying conditions of temperature, humidity and motion that are inherent on a sailing vessel. >> On Jul 30, 2010, at 9:20 AM, Craig Jungers wrote: >> The clock would then only have to remain within spec for 24 hours AND >> MEASURE LOCAL TIME and not for months or years to maintain >> synchronism with >> Greenwich. Presumably there were enough stars visible in both the >> southern >> and northern hemispheres so that Cook in Australia could use the >> tables >> developed at Greenwich TO TRY OUT THE LUNAR METHOD........... >> >> Thinking this over, the ancient Pacific navigators could have used >> very > much the same system using a sand-clock calibrated for 24 hours. > Accuracy > would not have been so great but then they would at least have had > some > measure of local time. What does local time have to do with figuring out longitude? You need a clock accurate enough to detect that if you sail 100 miles west the day is longer than if you travel 100 miles east. That is not a sand clock. And they did not have sand clocks anyway. They had no glass. You try and make a even vaguely accurate sand clock out of the materials that they had and sell it to your tribe as something that was useful. It is implausible that the natives were aware that the day was shorter when they sailed east than when they sailed west. This is awfully sophisticated stuff and would require a lot of formal experimentation -- the earth is round, it rotates on its axis etc. What would even impel them to want to make an accurate sand clock? They were not trying to run a train system. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
On Sun, Aug 8, 2010 at 5:48 PM, Robert Livingston <bearboat2_at_comcast.net>wrote: > > > What does local time have to do with figuring out longitude? You need a > clock accurate enough to detect that if you sail 100 miles west the day is > longer than if you travel 100 miles east. That is not a sand clock. > Your line of longitude is exactly under the sun at its zenith measured from Greenwich. Your line of latitude is calculated from the elevation of the sun at zenith. You can get an approximation of your longitude if you take a noon sight. The trouble being that the sun "hangs" at zenith for a period of time that makes this calculation only an approximation. And you'd need the time. So measuring your longitude from Greenwich does need accurate time. But you can get a bit more sloppy if you are only measuring a couple hundred miles from one location to another. You wouldn't need any real concept of "longitude" either... just a concept of the earth being round and some reference points. Local noon plus or minus the elapsed time would give you a rough approximation of how far east or west you traveled. It wouldn't be very accurate... and it would have to be referenced to a departure point - but it could give you some idea of when you might expect to see your destination over a relatively short passage. For instance.... if they had a way of measuring 24 hours then if the sun were at zenith exactly 24 hours after they started their "clock" then they would not have moved much in longitude. They almost certainly didn't understand degrees... but they could understand concepts such as "the sun begins to descend 1 hour after the "clock" reaches zero" would be, perhaps, the next group of atolls west. And they did not have sand clocks anyway. They had no glass. You try and > make a even vaguely accurate sand clock out of the materials that they had > and sell it to your tribe as something that was useful. Ok... how about a sand coconut? I'm merely offering up suggestions that seem to me to be more plausible than reading the pattern of the waves or somehow "just knowing" where they were. They could clearly move around in primitive craft over an area of thousands of square miles. Running down the latitude really only works well for going downwind. Upwind, where you need to tack, you'd also need to keep track of time somehow. Otherwise you risk missing the island because you extended one leg of the tack too far. Although it probably works ok for continents. :P Craig Jungers Moses Lake, WA www.nwkayaking.net *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
PeterO wrote ........The clock would then only have to remain within spec for 24 hours and measure and not for months or years to maintain synchronism with Greenwich. Presumably there were enough stars visible in both the southern and northern hemispheres so that Cook in Australia could use the tables developed at Greenwich to try out the lunar method........... Robert wrote .......Not really. The only useful clock is a VERY accurate one. You cannot stay linked with Greenwich by using an inaccurate clock and "correcting" it for local time. For one thing, when you are actually moving east west, local time "noon to noon" is no longer exactly 24 hours. In fact, it is the discrepancy that you are trying to detect to see how far east west you have gone............... G'Day Robert I was trying to explain that there is no need at all to use a clock to stay linked to Greenwich or any other longitudinal reference point when navigating by the stars, moons and planets. The lunar method implies this. The navigator would need a record or memory of their relative locations at particular days of the year and times of the night. Days of the year and times of the night can be measured in many ways without the need for sophisticated manufacturing and star maps were a commonplace. Some articles describing the techniques of Polynesian navigation. http://www.penn.museum/sites/navigation/intro.html http://www.teara.govt.nz/en/canoe-navigation/2 All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Peter: Seems like a terrible waste of 'roos. Bradford R. Crain Quoting PeterO <rebyl_kayak_at_energysustained.com>: > Brad wrote > .........Craig: Is the answer to the last question kangaroos?........... > > Cook wrote in his journal > http://southseas.nla.gov.au/journals/cook/contents.html > .......... > 17 April 1770 > > Tuesday 17th At 2 PM the wind came to WSW at which time we tack'd and stood > to the NW, before 5 oClock we was obliged to close reef our topsails having > a strong gale with very heavy squals, about this time a small land bird was > seen to pearch upon the riging, we sounded but had no ground with 120 > fathoms of line. At 8 oClock we wore and stood to the Southward until 12 at > night than wore and stood to the NW untill 4 AM when we again stood to the > Southd haveing a fresh ^gale at WSW attend with squals and dark hazey > unsettled weather untill 9 oClock at which time it fell little wind and the > weather ^soon after clear'd up which a little after a 11 gave us an > oppertunity of takeing several observations of the Sun and Moon the mean > result of which gave 2070..56' West Longitude from the Meridion of > Greenwich, from these observations the Longitude of the Ship at Noon was > 2070..58' and by the Log 2080..20' the difference being on^ly 22' and ^this > error may as well lay in the one as the other, our Latitude at noon was > 390..36' So and Longde made from Cape Farewell 220.22' Wt > ........... > > G'Day, > > Cook didn't make any mention of kangaroos in his journal Brad:~) However, he > was trained in astronomy and had astronomers with him for measuring the > transit of Venus in Tahiti. I think he was also on the Board of Longitude > and would have been well aware of the tables produced by Warner and > Maskelyne. I was well pleased to have found his journal entry above. It > looks as if Cook might have used a process such as recalibrating his clock > for local time every day against sunrise, sunset and noon. The clock would > then only have to remain within spec for 24 hours and not for months or > years to maintain synchronism with Greenwich. Presumably there were enough > stars visible in both the southern and northern hemispheres so that Cook in > Australia could use the tables developed at Greenwich. Cook was within a > degree of longitude when he reached the equator after surveying the east > coast of Australia on his first voyage. As Robert said it was such a tricky > method and judging from the above journal entry not much better than using > the kind of clock that was available prior to Harrison. When Cook went on > his 2nd voyage he took along a Harrison clock. > > Robert, Longitude is a wonderful book and the illustrated version is well > worth getting, it has a great many side notes that are missing from the text > only version. > > All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Mark wrote And, as others have pointed out, the position of the moon also gives a clue. Craig wrote: But this is useless for determining longitude because all you can measure is high noon. G'Day Craig and Mark, Two methods tried were one based on an idea of Galileo's that used Jupiter's moons. This was impractical as it could be flawed by the slightest inadvertant movement, and a second called the lunar distance method developed by Johannes Warner, which the Astronomer Royal Maskelyne used successfully on a voyage to St Helena. In the lunar method you read the time when the moon was adjacent to a star or a series of stars and compared local time against tables of standard times of the same measurements at a reference location. These tables might have been the origin of the 48 books you mentioned earlier? Both methods had the effect of reducing the need for maintaining a clock's accuracy over weeks or months, but I don't know how accurate the measured time had to be. Then there was the barking dogs and sympathetic powder, an obvious method to "the prepared mind":~) All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
If you interest has been peaked by this discussion, I would recommend a popular and well-written book on the topic of Longitude. Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time The English government put up a good deal of money to try and get a solution. The competition was between clock makers ( an accurate clock useable on a ship solves the problem) the approaches using lunar measurements. Ultimately, the clock approach won. Obtaining the lunar measurements was an exacting challenge. Wikipedia has summary discussion. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
The hotshot Europeans at the time could not tell how far around the globe they were. At a time when the Europeans had no answer, the Pacific navigators new latitude by the north star and by the position of other stars at their zenith. Those two sentences serve to imply that the Europeans could not tell latitude from the stars which is incorrect and it implies that the natives could tell longitude which is incorrect. > True. But Chuck specifically said that they could determine true > east and west from the stars. My gut reaction to this was "BS" but > upon thinking it over I believe that knowing the BAND of stars that > ring the equator could give them clues to true east and true west > (independently of the sun). Of course, keeping Polaris to your > starboard or port would also work; as long as you were far enough > above the equator to see Polaris. > > I suspect the Pacific Navigators did the same thing as the European > Navigators; sailed to a latitude well east (or west) of their > destination and turned the proper direction. There is even a name > for this: "running down the latitude". > > > Craig Jungers > Moses Lake, WA > www.nwkayaking.net *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
First off, I'm not a sailor at all so you can take what I write about navigation for what it's worth. Anyway.. and it probably came from the TV series on longitude, It wan't just that we were pretty good at determining latitude, but specifically Northern latitudes. That was why Vasco da Gama's voyage around Africa was considered so perilous. Once we went past the Ivory Coast or thereabouts, the North Star vanished from view. He was also seeing constellations and stars completely unfamiliar to european navigators. And he had to figure out where he was using them. Surely he had a compass so knew where north might be, but they already knew about the complications of magnetic declination but had no knowledge of its effect so far south. We certainly had more objective instruments to use, such as quarterstaffs and astrolables. So, doing that navigation in european terms involved use of such instruments and the accumulation of data, and learning to interpret its meaning. That's not too different from the Pacific navigators who used different cues, perhaps, but over the generations had reached conclusions about their reliability and how to interpret them... Joe P. >The hotshot Europeans at the time could not >tell how far around the globe they were. At a time when the Europeans >had no >answer, the Pacific navigators new latitude by the north star and by the >position of other stars at their zenith. > >Those two sentences serve to imply that the Europeans could not tell >latitude from the stars which is incorrect and it implies that the >natives could tell longitude which is incorrect. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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