# TIGHAR

## Amelia Earhart Search Forum => Celestial choir => Topic started by: Craig Romig on August 08, 2011, 12:33:12 PM

Title: 281 north
Post by: Craig Romig on August 08, 2011, 12:33:12 PM
where is 281nm north of the equater?  does anyone have  google corrdinates of it? it is suppose ot be a land mass. http://tighar.org/Publications/TTracks/1993Vol_9/cosmic.pdf
Title: Re: 281 north
Post by: Harry Howe, Jr. on August 08, 2011, 01:56:08 PM

Craig
Let's try an approximation from first principles.
Assume about 6000nm along the earth's surface from equator to Pole i.e. 90 degrees.  That equates to about 67 nm per degree and 281nm equals about 4.19 degrees N ( about 4 degrees 11.4 minutes).  I wonder what latitude she meant, but apparently she couldn't be bothered to correctly give her position.
And that is why the "searchers" assumed she meant 281nm  North of Howland and went to search there.  Sloppy communication will do it every time.
Title: Re: 281 north
Post by: Craig Romig on August 08, 2011, 03:22:24 PM
i just want to know 281 miles north of the equater is. 281 south is gardner island.
Title: Re: 281 north
Post by: Harry Howe, Jr. on August 08, 2011, 04:18:27 PM

Craig
In my opinion, Amelia transmitted "The equator is 281 nm North..."  i.e. she was at 4 degrees 12 minutes South latitude, i.e. on Gardner Island. Part of the transmission was garbled or Betty just caught the latter part of it  Question is: Why didn't AE just say that they were on Gardner Island?  Sure would have helped the "Searchers" look in the right quadrant.
Title: Re: 281 north
Post by: Bruce Thomas on August 08, 2011, 04:36:43 PM

Craig
Let's try an approximation from first principles.
Assume about 6000nm along the earth's surface from equator to Pole i.e. 90 degrees.  That equates to about 67 nm per degree and 281nm equals about 4.19 degrees N ( about 4 degrees 11.4 minutes).

Craig
In my opinion, Amelia transmitted "The equator is 281 nm North..."  i.e. she was at 4 degrees 12 minutes South latitude, i.e. on Gardner Island.

Harry, your assumption that the distance from the equator to one of the poles is 6000 nautical miles is seriously overstated.  The true distance is only 90% of that.  One degree of latitude is almost precisely one nautical mile 60 nautical miles (gee, what a coincidence! :D).  Therefore, your statement that Gardner Island is at 4 degrees 12 minutes South latitude is also wrong.  Divide 281 nautical miles by 60 and the result is 4.6833 to four decimal places.  That equates to 4 degrees 41 minutes South latitude.  Now fire up Google Earth and you'll see that's the latitude at the ocean entrance to Baureke Passage on Nikumaroro.

i just want to know 281 miles north of the equater is. 281 south is gardner island.

Craig, there is nothing 281 nautical miles north of the equator at the longitude of Howland Island ... just Pacific waters for as far as the eye can see.
Title: Re: 281 north
Post by: Harry Howe, Jr. on August 08, 2011, 05:26:42 PM

bruce
Actually, if we must insist on being  sticklers, By definition, one nautical mile is equal to the distance covered at the equator by one minute of arc, not one degree.
When I said "Approximation"  that's what I meant.  Had I meant "exactly" then I would have used my computer to calculate things and specified the time of day, the day of the week, the week of the month, the month of the year and the temperature of the water around the point in question (that is if I knew what longitude the point was at.

My point was that AE made a mistake and it was a costly mistake.
Title: Re: 281 north
Post by: Gary LaPook on August 08, 2011, 07:35:04 PM

Craig
Let's try an approximation from first principles.
Assume about 6000nm along the earth's surface from equator to Pole i.e. 90 degrees.  That equates to about 67 nm per degree and 281nm equals about 4.19 degrees N ( about 4 degrees 11.4 minutes).

Craig
In my opinion, Amelia transmitted "The equator is 281 nm North..."  i.e. she was at 4 degrees 12 minutes South latitude, i.e. on Gardner Island.

Harry, your assumption that the distance from the equator to one of the poles is 6000 nautical miles is seriously overstated.  The true distance is only 90% of that.  One degree of latitude is almost precisely 60 nautical miles (gee, what a coincidence! :D).  Therefore, your statement that Gardner Island is at 4 degrees 12 minutes South latitude is also wrong.  Divide 281 nautical miles by 60 and the result is 4.6833 to four decimal places.  That equates to 4 degrees 41 minutes South latitude.  Now fire up Google Earth and you'll see that's the latitude at the ocean entrance to Baureke Passage on Nikumaroro.

i just want to know 281 miles north of the equater is. 281 south is gardner island.

Craig, there is nothing 281 nautical miles north of the equator at the longitude of Howland Island ... just Pacific waters for as far as the eye can see.

Nor is there anything 281 nautical miles south of the equator "at the longitude of Howland Island ... just Pacific waters for as far as the eye can see."

gl
Title: Re: 281 north
Post by: Gary LaPook on August 08, 2011, 08:00:44 PM
where is 281nm north of the equater?  does anyone have  google corrdinates of it? it is suppose ot be a land mass. http://tighar.org/Publications/TTracks/1993Vol_9/cosmic.pdf

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There are only two pieces of dry land in the Pacific at 4° 41' north latitude (281 NM north of the equator) between the  Philippines at 125° east longitude and South America. They are Ebon Island at 168° 41' east longitude (881 NM west of Howland) and Washington Island at 160° 23' west longitude (975 NM east of Howland.)

gl
Title: Re: 281 north
Post by: Gary LaPook on August 08, 2011, 08:30:02 PM

bruce
Actually, if we must insist on being  sticklers, By definition, one nautical mile is equal to the distance covered at the equator by one minute of arc, not one degree.
When I said "Approximation"  that's what I meant.  Had I meant "exactly" then I would have used my computer to calculate things and specified the time of day, the day of the week, the week of the month, the month of the year and the temperature of the water around the point in question (that is if I knew what longitude the point was at.

My point was that AE made a mistake and it was a costly mistake.
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As long as we are being sticklers, one minute of arc along the equator is not a nautical mile, it is a geographic mile and is 6,087 feet long. Nor is a nautical mile one minute of latitude as that varies from 6,045 feet at the equator to 6, 108 feet at the poles. This is due to the bulge of the equator due to centrifugal force making it further around the earth along the equator than it is going north and south. The nautical mile is based on a perfect sphere having the same area as the earth. The same assumption is made for the purposes of navigation and the slight difference between the nautical mile and the length of a minute of arc on the real earth are ignored. On such a sphere there are 21,600 NM around the circumference along any great circle since there are 360 degrees around the great circle and there are 60 NM per degree (360X60=21,600.) Since there are 90 degrees from the equator to the north pole there are 5,400 NM along the same arc (90X60=5,400.)
Going back to first principles, the meter was originally defined as one-ten-millionth of the distance from the equator to the north pole. Since there are 5,400 NM covering the same distance, divide 10,000,000 by 5,400 and you find the length of a nautical mile is 1,852 meters. Since one meter is 3.2808390 feet a nautical mile is 6,076.11548556 feet.
(In case someone notices that the division doesn't work out to be exactly 1852 meters (1,851.85), that problem was dealt with by international agreement making it 1,852 meters exactly.)
gl
Title: Re: 281 north
Post by: Harry Howe, Jr. on August 08, 2011, 10:08:48 PM

Very good, Gary. Only one addition...  The meter was defined as one ten millionth (ten to the minus seventh power) of the distance on the surface of the earth from the North Pole to the Equator along a Meridian that passed thru Paris, France, and only that meridian .  The secondary standard became the distance between two scribed marks on an Iridium rod kept under controlled environmental conditions in Paris, France.

Obviously, my first mistake was writing nautical miles when I really meant statute miles (referring to one- fourth of the approximate circumference of the earth).Well, we beat that subject to death  LOL
Title: Re: 281 north
Post by: Gary LaPook on August 09, 2011, 12:37:20 AM

Very good, Gary. Only one addition...  The meter was defined as one ten millionth (ten to the minus seventh power) of the distance on the surface of the earth from the North Pole to the Equator along a Meridian that passed thru Paris, France, and only that meridian .  The secondary standard became the distance between two scribed marks on an Iridium rod kept under controlled environmental conditions in Paris, France.

Obviously, my first mistake was writing nautical miles when I really meant statute miles (referring to one- fourth of the approximate circumference of the earth).Well, we beat that subject to death  LOL

-----------------------
It took seven years starting in 1792 during all the turmoil of the French Revolution and the Terror. Two French astronomers very accurately determined the latitudes of Barcelona and Dunkerque by celestial navigation techniques. Then the distance between those two latitudes was determined by triangulation giving a baseline of about 600 miles from which they could calculate the length of the meridian.

gl
Title: Re: 281 north
Post by: Craig Romig on August 09, 2011, 01:20:39 AM
where is 281nm north of the equater?  does anyone have  google corrdinates of it? it is suppose ot be a land mass. http://tighar.org/Publications/TTracks/1993Vol_9/cosmic.pdf

------------------------------------------------------------------------------
There are only two pieces of dry land in the Pacific at 4° 41' north latitude (281 NM north of the equator) between the  Philippines at 125° east longitude and South America. They are Ebon Island at 168° 41' east longitude (881 NM west of Howland) and Washington Island at 160° 23' west longitude (975 NM east of Howland.)

gl

ok thanks. thats all i was interested in about the page.
Title: Re: 281 north
Post by: Harry Howe, Jr. on August 09, 2011, 12:29:30 PM

Craig
About 700 nm,or so, West of Howland and stretching for many degrees of latitude N is a chain of islands called The Marshalls.  4 degrees 40 minutes N or so (281 nm) is in that chain. For example  Bairiki is at 1.09 degrees N and 172.5 E.  Generally though, it's mostly empty ocean.

Craig, Bruce, Gary  This is fun.  Have a great day. 8)
Title: Re: 281 north
Post by: Gary LaPook on August 09, 2011, 07:13:10 PM

Craig
About 700 nm,or so, West of Howland and stretching for many degrees of latitude N is a chain of islands called The Marshalls.  4 degrees 40 minutes N or so (281 nm) is in that chain. For example  Bairiki is at 1.09 degrees N and 172.5 E.  Generally though, it's mostly empty ocean.

Craig, Bruce, Gary  This is fun.  Have a great day. 8)

-------------------------------------------------
Ebon Island is the only land in the Marshall Island chain near the 4° 41' north latitude that this speculation is about and it is about 880 NM west of Howland. The only other islands in this chain that are anywhere near that latitude are  Makin Island at 3° 23' north is 78 NM south of that latitude and  Jaluit at 5° 46' north is 65 NM north of the 4° 41' north latitude. The nearest of these islands is at least 440 NM west of Howland.

Also see my prior posts:

https://tighar.org/smf/index.php/topic,384.47.html