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Author Topic: Earhart's Electra found in Papua New Guinea?  (Read 73822 times)

Ashley Such

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #15 on: September 06, 2010, 04:52:36 PM »

I don't think we need to get too excited about these reports around New Guinae.  AE flew for 11 hours from Lae, talked to Itaska  with signal getting louder, talked about going 157-337, Gas running low, all good information. For her to show up over there on 3 hours of fuel is ridiculous

Agreed with you, there! I personally don't see how she could be at that LOP, and be able to turn back to New Guinea... Seems impossible.
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Martin X. Moleski, SJ

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #16 on: September 06, 2010, 09:37:04 PM »

... I personally don't see how she could be at that LOP, and be able to turn back to New Guinea. ...

A Line of Position is just a straight line on a map.

It doesn't have any particular location.

From anywhere in the world, one can fly on the straight line indicated by 337-157 on a compass.

The last transmission doesn't tell us anything about how far east or west AE and FN were at the time they made the transmission.

A navigator with access to the same tables that Fred used that morning might be able to draw a region of probability about where the aircraft must have been IF Fred derived the 337-157 line from a dawn observation--I'm not sure how big the region is where that line would be derived from sighting sunrise.  But in and of itself, the message does not say how close they were to Niku or how far away they were from Papua New Guinea.

LTM,

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Ashley Such

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #17 on: September 06, 2010, 10:01:59 PM »

A Line of Position is just a straight line on a map.

It doesn't have any particular location.

From anywhere in the world, one can fly on the straight line indicated by 337-157 on a compass.

The last transmission doesn't tell us anything about how far east or west AE and FN were at the time they made the transmission.

A navigator with access to the same tables that Fred used that morning might be able to draw a region of probability about where the aircraft must have been IF Fred derived the 337-157 line from a dawn observation--I'm not sure how big the region is where that line would be derived from sighting sunrise.  But in and of itself, the message does not say how close they were to Niku or how far away they were from Papua New Guinea.

Oh, thanks for the information, Marty. :)
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Ric Gillespie

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #18 on: September 07, 2010, 09:57:26 AM »

With all due respect, a Line of Position is more than just a straight line on a map.  When Fred Noonan shot the sun on the morning of July 2nd and put a 157/337 line on his map, he could be sure that he was somewhere on that line.  Realistically, the "line" might be as much as ten miles wide in an East/West sense and he couldn't know for sure where on the line he was in a North/South sense, but it was better than a dead-reckoning guess.  Go to What is the significance of Earhart’s statement “We are on the line 157/337”? for a good explanation of Line of Position.
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Kevin Weeks

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #19 on: September 07, 2010, 10:12:59 AM »

With all due respect, a Line of Position is more than just a straight line on a map.  When Fred Noonan shot the sun on the morning of July 2nd and put a 157/337 line on his map, he could be sure that he was somewhere on that line.  Realistically, the "line" might be as much as ten miles wide in an East/West sense and he couldn't know for sure where on the line he was in a North/South sense, but it was better than a dead-reckoning guess.  Go to What is the significance of Earhart’s statement “We are on the line 157/337”? for a good explanation of Line of Position.


okay, now I don't feel so bad. I had read that link you posted a little while back and understood it as how you explained it in this post, not as moleski put it simply as a compass heading.
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Martin X. Moleski, SJ

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #20 on: September 07, 2010, 05:17:24 PM »

With all due respect, a Line of Position is more than just a straight line on a map.

No.  That's all it is.  The term refers to a line drawn as the result of doing an observation.  The ideal is to get two LOPs to cross.  Then you know that you are almost certainly at the point of intersection (or nearby, at any rate).

"A line indicating a series of possible positions of a craft, determined by observation or measurement. Also known as position line" (Sci-Tech Dictionary).

A Line of Position is not a "fix."  The "fix" comes from having Lines of Position cross each other.

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When Fred Noonan shot the sun on the morning of July 2nd and put a 157/337 line on his map, he could be sure that he was somewhere on that line.

But Fred didn't tell us the time at which he made that observation.  The terminator swept out that line all across a very large region of the Pacific that morning.  With the knowledge of what time he observed the sun, plus knowledge of his altitude, plus some tables, plus some calculations, FRED could draw a line on his charts and say, "We were on that line at such-and-such a time this morning.  Now I all have to do is dead-reckon to a parallel Line of Position drawn through Howland Island.  When we reach that advanced LOP, which I have drawn on my chart to aid dead-reckoning, then we will know that it is time to turn north or south."

Note that both LOPS are 337-157.  That's because they are parallel.  You can't tell one apart from the other by the compass headings that define them.

Without Fred sending us his chart and without any record of WHEN he made the sun observation, we are ignorant of something he knew.

From the information that his two LOPs were 337-157, we cannot say how far apart their were on his chart.

What we could know is how big a range in the South Pacific would have a 337-157 line drawn by the terminator between night and day on 2 June 1937.  The angle of the line drawn by the terminator changes with one's location at the time of the observation because the earth is a globe, not a circle, and the line between night and day is curved around that globe.

We can (and do), of course, surmise that AE's transmissions about being 200 and 100 miles from Howland give us some idea of when Fred drew the two LOPs on his charts and started counting down the distance from one to the other.  But that extra information is not encoded by saying, "The dawn LOP on my chart and the advanced LOP that I drew through Howland is 337-157."

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Realistically, the "line" might be as much as ten miles wide in an East/West sense and he couldn't know for sure where on the line he was in a North/South sense, but it was better than a dead-reckoning guess.

I never said it was a guess.  What I said was that from the information given that their advanced LOP was 337-157, we do not know where they were when Fred took the dawn observation.  He knew (if his watch was keeping good time); we don't know.

Go ask a navigator where the line 337-157 is in the Pacific.  He will tell you that is everywhere and nowhere.  Any time you're flying, you can turn to a heading of 337 or 157. 

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Go to What is the significance of Earhart’s statement “We are on the line 157/337”? for a good explanation of Line of Position.

Go to Marine Navigation courses: Lines of Position to see how lines drawn on a chart lead to a fix.

Go to Lines of Position to see how such lines are drawn on charts from observation of celestial bodies.

"Lines of position are constructed on a geographic map from observational data and indicate the observer’s position. For complete determination of a position, it is necessary to construct at least two lines of position, whose intersection corresponds to the unknown location. Here, to ensure a reliable determination, both lines of position must intersect at an angle that is not too acute—at least 30°. If the lines of position have several, usually two, points of intersection, it is not difficult to select the necessary point, since the approximate location of the point of observation is usually known. For the same reason, observers often restrict themselves to constructing only a short segment near the approximate position of the observer rather than an entire line of position. This segment is replaced with the tangent to the line of position.

"Lines of position are used extensively in navigation and aviation to determine the position of a ship or aircraft from the observed altitudes of two celestial bodies. This method was first published by the American sailor T. Sumner in 1843. Such celestial lines of position are called Sumner lines. A convenient, simple method of calculating and constructing these curved lines on a map was demonstrated in 1849 by the Russian sailor M. A. Akimov. Since the late 19th century, celestial lines of position have been calculated and constructed by an even more convenient method proposed by the French sailor M. St.-Hilaire in 1875."

Source: The Great Soviet Encyclopedia.
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           Marty
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Martin X. Moleski, SJ

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #21 on: September 07, 2010, 05:59:21 PM »

With all due respect, a Line of Position is more than just a straight line on a map.  When Fred Noonan shot the sun on the morning of July 2nd and put a 157/337 line on his map, he could be sure that he was somewhere on that line.  Realistically, the "line" might be as much as ten miles wide in an East/West sense and he couldn't know for sure where on the line he was in a North/South sense, but it was better than a dead-reckoning guess.  Go to What is the significance of Earhart’s statement “We are on the line 157/337”? for a good explanation of Line of Position.
okay, now I don't feel so bad. I had read that link you posted a little while back and understood it as how you explained it in this post, not as moleski put it simply as a compass heading.

Let me quote from Ric's link: "The numbers refer to degrees on a compass. Amelia was saying that they were on a line that points 157 degrees (roughly southeast) one way, and 337 degrees (roughly northwest) the other way.

"Of course, you are on a 157 337 line right now and it can’t tell you anything about where you are ..."

That is quoting the page to which Ric referred.  Even when you add in the idea that this was a compass heading given by the line between night and day, you still haven't specified how big the region is out in the Pacific where an observer could have derived that line from seeing the sun rise, checking the chronometer, consulting tables, and doing some calculations to account for the altitude of the aircraft above the surface of the earth.  Saying that AE and FN were on a LOP of 337-157 at sunrise does not tell us how far east or west they were--because we don't know what time they made that observation.  The statement that "the LOP was 337-157" does not contain that crucial information.  There is a limit to how far west they could have been, if we make some assumptions about their latitude--but, so far as I know, no one at TIGHAR has done the calculation.

The closer you get to the poles, the closer the LOP drawn by the dawn terminator would approach to 270-90 (E-W).  If the earth weren't tilted 23.5 degrees on its axis, at the equator the dawn LOP would always be 360-180 (N-S).  But the earth is tilted and the dawn LOP is going to vary continuously from one observation point as the days pass until a full solar year has elapsed.  I don't know how refined the tables were--that is, whether the steps were by day, week, or month.  But it's not hard to see the issue.  For a moment, hold the earth still.  Hold it in your hand so that the terminator west of Howland Island, not too far north of the equator, has a tangent of 337-157 from the circle of light falling on the globe whose center is in the sun.  With your other hand, drop the sun down until it reaches the winter solstice--the most southern point of its course.  Your dawn LOP is now going to be closer to N-S than it was on 2 July.  Bring the sun back up through the next six months to the summer solstice in June--the most northern part of the sun's course.  The LOP near Howland is going to be more E-W than it was six months before.  On 2 July, the sun has started back down and has about 1/13th of the distance to the next solstice.  I can't picture whether that is a 2 degree difference or a 4 degree difference from LOP observed at the summer solstice, but it is in that neighborhood, I think. 

If there were no tilt of the earth, the LOP observed from the dawn sighting would be the same every day.  I think that the difference between the solstice dawn LOPs must be 23.5 degrees every six months, for a total cycle of 47 degrees.  The sun appears to be 23.5 degrees above the equator at our summer solstice and 23.5 degrees below the equator at our winter solstice.  If so, the dawn LOP observed from the same place would vary a little less than a degree per week.
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           Marty
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Ashley Such

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #22 on: September 07, 2010, 08:11:28 PM »

Woah. Gentlemen, I thank you for both of your help (Ric & Marty). :)

Didn't mean to start a little debate here. :P
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Martin X. Moleski, SJ

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #23 on: September 08, 2010, 12:57:32 PM »

Ric's likely correct in the overall sense, in my thinking - there are too many details established about proximity to Howland to lead me to believe that AE somehow wound up so close to her point of origin...

I'm betting on the Niku hypothesis.  I'm not arguing against it.  I'm trying to clarify how to visualize and state it correctly.  We do not know where on his charts Fred drew the line he derived from his dawn sighting.  There is a very large area on the face of the earth where a LOP of 337-157 would be derived from watching the sun rise.  That tangent to the terminator travels with the terminator across the face of the earth 24 hours a day.  We are unable to put our finger on a map of the Pacific and say, "That's it.  That's the line that AE and FN were on when sun rose."  From the information that the LOP was 337-157, we know roughly what region they were in--on the assumption that Fred made a good observation, that his chronometer and the plane's altimeter were accurate, and that his calculations were correct.
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That said, IF FN did take the shot at a reliable time by his timepiece at sunrise, then the LOP would most definitely be along a 'certain line' of the surface of our earth (or the Pacific Ocean, in this case) - and at 337 - 157 as stated as a function of bearing to the sunrise.

Somehow I suspect the 'new find' will turn out to be another airplane, perhaps another Lockheed, not AE's - and would bet on TIGHAR's current notion on which one it probably is.  That too said, it will be most interesting to see what really comes of this - we're in the middle of a long-standing mystery that has had some weird turns in it at times, so who really knows until 'they' can establish what this long-lost / newly-found bird really is.

Agreed on both counts.
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Alan Williams

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #24 on: September 08, 2010, 03:01:44 PM »

As I've read posts to this thread what I've found most interesting isn't the technical details of one navigational alternative or another but the very real fact that items have been found on Niku that have been identified to be virtually exactly what the AE/FN crew might have been carrying. So what potentially interests me most isn't if the discovered Electra is THE Electra (although that is interesting and remains to be seen), but that if the discovered Electra is the AE Electra, then how did all those artifacts turn up on Niku?...

Yeah - I believe the potentially most interesting mystery would be that if in the case AE's Electra was no where near Niku then where did the  post-loss transmissions come from? Where did the artifacts come from? Who's bones were those? If AE/FN weren't on Niku then I believe we'd really have the greatest mystery of recent history...
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Ric Gillespie

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #25 on: September 08, 2010, 07:20:09 PM »

We do not know where on his charts Fred drew the line he derived from his dawn sighting.

I agree but I would submit that it doesn't matter.  He could have made his observation at dawn or any time over the next hour or so and still gotten a 157 337 LOP.  The particular time at which he made his observation told him where to draw the line on his map. Wherever he was, he apparently drew his line and then advanced it by dead reckoning to fall through his intended destination. He then calculated his groundspeed and determined how much time it would take the Electra to cover the distance between the two parallel lines.  If he was dead on course in a north/south sense, when the time expired Howland should appear.  He may have passed AE a note that read something like "ETA 1907" (they were using Greenwich time). It's unlikely that Earhart understood what Fred was doing and that the ETA he gave her was for reaching the advanced LOP, but not necessarily Howland. When 1907 arrived and Howland didn't she may have scanned the horizon for five minutes and then radioed at 1912 (0742 Itasca time), "We must be on you but cannot see you."  That phrase - we MUST be on you - conveys much more certainty than Noonan can possibly have had and almost certainly reflects AE's misunderstanding rather than Noonan's calculation. All he could know is that they had reached the advanced LOP at a point either north or south of Howland. The logical course of action then was to search north and then south along the advance LOP hoping to spot Howland.  And that, in fact, is exactly what AE said they were doing an hour later in her last in-flight transmission heard by Itasca - probably reading from another note from Fred.
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Martin X. Moleski, SJ

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #26 on: September 08, 2010, 10:04:16 PM »

We do not know where on his charts Fred drew the line he derived from his dawn sighting.
I agree but I would submit that it doesn't matter.  He could have made his observation at dawn or any time over the next hour or so and still gotten a 157 337 LOP.  The particular time at which he made his observation told him where to draw the line on his map. Wherever he was, he apparently drew his line and then advanced it by dead reckoning to fall through his intended destination. He then calculated his groundspeed and determined how much time it would take the Electra to cover the distance between the two parallel lines.  If he was dead on course in a north/south sense, when the time expired Howland should appear.  He may have passed AE a note that read something like "ETA 1907" (they were using Greenwich time). It's unlikely that Earhart understood what Fred was doing and that the ETA he gave her was for reaching the advanced LOP, but not necessarily Howland. When 1907 arrived and Howland didn't she may have scanned the horizon for five minutes and then radioed at 1912 (0742 Itasca time), "We must be on you but cannot see you."  That phrase - we MUST be on you - conveys much more certainty than Noonan can possibly have had and almost certainly reflects AE's misunderstanding rather than Noonan's calculation. All he could know is that they had reached the advanced LOP at a point either north or south of Howland. The logical course of action then was to search north and then south along the advance LOP hoping to spot Howland.  And that, in fact, is exactly what AE said they were doing an hour later in her last in-flight transmission heard by Itasca - probably reading from another note from Fred.

In other words, the evidence of how close they got to Howland Island is not in the words "flying the LOP 337-157," but in an evaluation of other data not contained in that transmission.

Which is the point I was making in reply to Ashley's remark that she could not believe that they could have reached 337-157, then made it back to Papua New Guinea.  "337-157" does not contain any of the information you give above which provides good reasons to think that they got so close to Howland that they could never have made it to Papua New Guinea.

As the earth rotates on its axis, there is always some region from which an observer could derive a LOP of 337-157 at dawn.  Those numbers, by themselves, without any other information, do not say "they came awfully close to Howland."
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Ric Gillespie

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #27 on: September 09, 2010, 06:40:45 AM »

"337-157" does not contain any of the information you give above which provides good reasons to think that they got so close to Howland that they could never have made it to Papua New Guinea.

As the earth rotates on its axis, there is always some region from which an observer could derive a LOP of 337-157 at dawn.  Those numbers, by themselves, without any other information, do not say "they came awfully close to Howland."

That's true, but we do have other information. We know that this 157 337 line was drawn at or near dawn on July 2, 1937.  Therefore the sun had to rise at 67° (90° to the LOP).  In other words, to see the sun rise at 67° on the morning of July 2, 1937 you had to be somewhere on a 157 337 line that, at its closest point, passed a couple hundred miles to the southwest of Howland.  The plane may not have been (and probably wasn't) awfully close to Howland, but from nowhere on that line was it possible for that airplane to return to New Guinea.
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Kevin Weeks

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #28 on: September 09, 2010, 10:02:26 AM »

I've got a couple navigation questions that don't necessarily fit into the normal lines of questioning.

we know the time that Earhart thought she was on howland, what time was it?

how long after that was she able to stay airborn? (would she have landed in the morning?)

my question is because I read on the forum that one of the popular reasons people are presuming that AE and N would go to the southeast corner of the island is because he would be able to get a fix on his position. My question is why would he?? it would take him longer and more effort to get there than derive his latitude and longitude from the sun sitting on the beach?? granted if he had more celestial bodies to site he could make a more accurate estimate of position but that would mean leaving the plane that was still able to transmit.

If they landed on gardner in the AM Noonan could have determined lat/long. by noon the next day.
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Ric Gillespie

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Re: Earhart's Electra found in Papua New Guinea?
« Reply #29 on: September 09, 2010, 11:18:50 AM »

we know the time that Earhart thought she was on howland, what time was it?
At 07:42 local time (1912 GCT) she said "We must be on you..."

how long after that was she able to stay airborn? (would she have landed in the morning?)

Of course, no one knows for sure how much fuel she had left at that point, but based on the airplane's known fuel load at departure and the known capabilities of the airplane she "should" have had about five hours left.

my question is because I read on the forum that one of the popular reasons people are presuming that AE and N would go to the southeast corner of the island is because he would be able to get a fix on his position. My question is why would he?? it would take him longer and more effort to get there than derive his latitude and longitude from the sun sitting on the beach?? granted if he had more celestial bodies to site he could make a more accurate estimate of position but that would mean leaving the plane that was still able to transmit.

If they landed on gardner in the AM Noonan could have determined lat/long. by noon the next day.

I agree. I don't see why Noonan would have to go anywhere to observe local noon to get his latitude or to take star sightings at night to determine his exact position.  If he did either of those things he should have been able to figure out where he was.  The absence of credible lat/long coordinates or any mention of an island name in any of the known post-loss radio messages makes me think that he was not able to do either of those things for whatever reason.  I see no reason to think they abandoned the airplane until forced to do so.  I think the move to the southeast end came much later.
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