Seeking Comments on New Date Line Theory

[Martin X. Moleski, SJ]

"Frederick Noonan Precomputed  a Running Sunset Fix for Amelia Earhart´s Flight from New Guinea to Howland , July 2 , 1937".

"Sunset" doesn't sound right.

It should be "sunrise," I think.

[h.a.c. van asten]

Moleski. No , sunset is correct , it here concerns the sunset fix near Nukumanu from wich it is derived that no great circle path has been flown.

[h.a.c. van asten]

Moleski. Noonan also computed a running sunrise fix , the concerning observation with the ship´s sextant caused a local hour angle error by which the island did not run in sight at ETA. Publshed EJN, July 2008.

[h.a.c. van asten]

Moleski. Howland would have come in sight at 1912 Z ,RDF failure became the navigation error not incurred. Hence, RDF failure became a problem , after sunrise with a 3min50sec time error which was not visible on the watch faces.

[h.a.c. van asten]

Moleski . Correction, delete former. Noonan also precompted a sunrise fix and checked by ship´s sextant insted of bubble sextant at sunset. By this a 3min50s local hour angle error was incurred , not visible on the watch faces .See EJN July 2008 "Where to Find Amelia Earhart´s Lockheed Electra. RDF failure became a problem after sunrise ; without the time error Howland would have run in sight at 1912 Z.

[Ric Gillespie]

Noonan also precompted a sunrise fix and checked by ship´s sextant insted of bubble sextant at sunset.

Why would he use a ship's sextant if he had an operational bubble octant?

By this a 3min50s local hour angle error was incurred , not visible on the watch faces .See EJN July 2008 "Where to Find Amelia Earhart´s Lockheed Electra. RDF failure became a problem after sunrise ; without the time error Howland would have run in sight at 1912 Z.

So all of your speculation hinges on a time error induced by Noonan using a ship's sextant instead of a bubble octant.  You also rely upon a highly skilled and experienced navigator not noticing a whopping 3 min 50 sec error.

[Ricker H Jones]

Mrs.L.Smith , By recomputing the 0720 radioed fixed position near Nukumanu island(s) , proof comes up that the great circle route seen in many maps , books and internet sites does not at all apply to the July 2nd flight. And it has been published : European Journal of Navigation , vol. 9 , no.1 , april 2011 : "Frederick Noonan Precomputed  a Running Sunset Fix for Amelia Earhart´s Flight from New Guinea to Howland , July 2 , 1937".

I would be very interested in reading the article you cite (in the European Journal of Navigation , vol. 9 , no.1 , April 2011).  Do you have a link to it in English? Or I could translate it if necessary.  Thanks.
Rick J

[h.a.c. van asten]

R.J. If you wish sned URL to hac.vanasten@gmail.com for electronic copy.

[h.a.c. van asten]

To R.C. The error was a local hour angle fault not visible on the watch face(s). Noonan , from his time with PANAM carried a mariner´s sextant for accuracy , as also given by Dutton , 1928 , Navigation and nautical Astronomy , art.31.l.p.348 , on advantages and disadvantages of the bubble versus ship´s sextant : "In any case (by using the bubble sextant, Ast), the pilot must fly the plane as steady as his skill permits while the sights are being taken. Because or the errors of the bubble sextant, the best results are obtained by flying very low and using the ordinary (=marine , Ast) sextant on the horizon" . The difference between 175453 GMT and 175103 GAT is 3m50s , it was with this difference that the aircraft was steered on the offset track , i.e. 3m50s too early for 11 miles westerly deviation from the over Howland , assumed position, advancedsun position line. 

[Ric Gillespie]

Noonan , from his time with PANAM carried a mariner´s sextant for accuracy

Not true.  In a May 11, 1935 letter to P.V.H. Weems describing his navigation methods on the Pan Am survey flights, Noonan wrote:
"Two sextants were carried - a Pioneer bubble octant, and a mariners sextant. The former was used for all sights; the latter carried as a "preventer"."

"Preventer" is an old nautical term for a back-up. There is no reason to think than Noonan ever used the mariner's sextant if the bubble octant was available.

The letter was subsequently published in the May 1938 issue Popular Aviation.

it would appear that your entire theory is based upon a a false premise.

[h.a.c. van asten]

Nikunau is shown in 01deg23´-S latitude in (p.e. Norie´s) tables of the era. The most probable route to Howland was : Lae-Gagan 533 mls ,Gagan-Nukumanu 341 , Nukumanu-Initial Point 165deg21´-E/01deg23´-S 458 , In.Pt.- Nikunau via Tabiteuea-Beru 766 , Nikunau - sunrise fix 348 (Nikunau-Howland = 498 mls loxo) , fix to In.Pt one line appr. 50 , In.Pt. to TOP (Turn off Pt) 102 , thence to Howland ass.posn. 30 miles. Total 2,628 miles planned. Initially , sunrise o.b. would have occurred earlier , but due to delay (weather off forecast) on the 1st leg to Nukumanu , 44 minutes , sunrise was seen later , i.e. at 175453 GMT , being the only reference occurrence after twilight. On the leg In.Pt. to Nikunau , every 20 minutes a navigation star came in A/c´s meridian so that one-star observation only was needed to stabilize piloting in the latitude by this composite sailing fashion.

[Walter Runck]

R.J. If you wish sned URL to hac.vanasten@gmail.com for electronic copy.

For those of us trying to digest your theory, perhaps you could attach the EJN article to a post in this forum?  Here is how you do it.

[Ricker H Jones]

The 0720z running sunset fix could have been difficult for Noonan.  If the sun's azimuth was, for example, 291 degrees, and the heading of the aircraft was 081 degrees, the port vertical stabilizer or other empennage components may have blocked the sight line from the aft cabin window.
Rick J

[h.a.c. van asten]

R.Jones . Angle for observation of sunset. A/c heading 079 T , sunset line 023-203 . Sight angle 079-23 = 56 degrees w.r.t. A/c´s axis , large enough for observarion through l.h. cabin door , magn.variation included ; window installed with special flat glass, no disturbance by vertical rudder. Proof by Noonan giving o.b. sunset coordinates for precomputed time point , by mathematics inviolably connected.

[Bob Brandenburg]

Perhaps you would share with us the details of your derivation of the sunset azimuth you cite for the 071930 GMT coordinates in your paper.