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--- glapook@pacbell.net wrote:

> Yes, I put up that web site to provide authoritive information about
> the process and accuracy of celestial navigation as practiced in the
> air in the 1937 time frame to allow everyone to evaluate for
> themselves TIGHAR's hypothesis. 

Were they at least open to the material that you posted? 

I pretty much soured on the TIGHAR group when the couple of items (and
other questions) that I tried to post to the list apparently got
"censored" by the moderator (I guess not being worthy of their time).
And from looking over their website it almost looks like a fund-raising
operation for the select few who actually get to go on the expeditions
(with the majority of the group apparently expected to provide the bulk
of the funds but only get to experience them vicariously).

> the celestial navigation using the single LOP landfall procedure 
> had suficent accuracy to locate an island as small as Howland.

Even allowing for unforeseen winds aloft? After all of those hours
without a good fix (other than maybe a running one from sun lines along
the way)?

> A knowledge of this technique is still required by federal aviation 
> regulations and this knowledge must be demonstrated on the flight
test
> for a Flight Navigator's Certificate.

I'm surprised they still offer that certificate (realistically, does
anyone even get them any longer?) - and much like the FEX (flight
engineer) one I thought they'd both been exiled as historical relics of
an earlier age.

> Based on the known accuracy of this technique (and I have done 
> it many times myself in flight) 

I keep meaning to ask if maybe you were a Navy or Air Force navigator
in a prior life.

> they should have been very close to Howland at the time of fuel 
> exhaustion and I have no explanation for their failure to find the 
> island.

Well, the only thing I can think of that would have prevented it would
be that they were a lot further off their intended course than they'd
realized - do you have a better theory than unforecast winds like I
mentioned earlier?

> I do know that they are not on Nikumoro (TIGHAR's hypothesis) which
> is 380 NM from Howland on a true course of 169�. TGHAR's hypothesis 
> is that they continued to follow this LOP all the way to that island
> (formerly, Gardner Island.) As anybody with any knowldge of CN knows,
> that during the three hour period necessary to fly from the vicinity
> of Howland to Nikumorro the azimuth of the sun would have changed
> significantly and there would be no LOP to follow to the vicinity of
> Nikumorro.

Agreed, unless that's where they ended up at their ETA because of being
so far off course.

--
GregR


--- glapook@pacbell.net wrote:

> 
> Yes, I put up that web site to provide authoritive information about
> the process and accuracy of celestial navigation as practiced in the
> air in the 1937 time frame to allow everyone to evaluate for
> themselves TIGHAR's hypothesis. The excerpted texts were contemporary
> or nearly contemporary navigation standard reference works. Read
> through the documents, especially the single LOP landfall procedure;
> accuracy of sextant LOP; and accuracy of DR position topics:
> 
> http://www.geocities.com/fredienoonan/topics.html
> 
> and you will see that the celestial navigation using the single LOP
> landfall procedure had suficent accuracy to locate an island as small
> as Howland. This technique was taught to thousands of WW 2 navigators
> and used sucessfully many, many times by those navigators to find
> island landfalls.  A knowledge of this technique is still required by
> federal aviation regulations and this knowledge must be demonstrated
> on the flight test for a Flight Navigator's Certificate. Look at item
> 34 on  Appendix A to Federal Aviation Regulation Part 63 available
> here:
> 
>

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=7901ef0a7d09b0a9b8b7132ad615a8eb&rgn=div9&view=text&node=14:2.0.1.1.3.3.1.7.13&idno=14
> 
> If the technique didn't work it would not have been taught as a
> standard technique for many years and it would not be on the Flight
> Navigator test today.
> 
> My "pet theory" is that they were utilizing the single LOP landfall
> procedure to find Howland as evidenced by their reporting being on
> the
> "157-337� LOP" which was obviously a sun line since the azimuth of
> the
> sun was 067� from the time of sunrise at Howland and remaining the
> same for almost an hour later, the time period of their approach to
> the island. Based on the known accuracy of this technique (and I have
> done it many times myself in flight) they should have been very close
> to Howland at the time of fuel exhaustion and I have no explanation
> for their failure to find the island.
> 
> I do know that they are not on Nikumoro (TIGHAR's hypothesis) which
> is
> 380 NM from Howland on a true course of 169�. TGHAR's hypothesis is
> that they continued to follow this LOP all the way to that island
> (formerly, Gardner Island.) As anybody with any knowldge of CN knows,
> that during the three hour period necessary to fly from the vicinity
> of Howland to Nikumorro the azimuth of the sun would have changed
> significantly and there would be no LOP to follow to the vicinity of
> Nikumorro.
> 
> gl
> 
> 
> On Jun 19, 11:32 pm, "Greg R."  wrote:
> > --- glap...@pacbell.net wrote:
> > > Here are excerpts from the 1937 N.A The first page shows the
> > > time of transit of the moon of the Greenwich meridian and
> contains
> > > a "Var. per hour" column, variation?
> >
> > Sounds "probable" to me...
> >
> > Thanks also for the Earhart/Noonan connection - is that your site
> by
> > any chance?. Up until recently that was another pet interest of
> mine
> > (and seems like I've seen your name pop up on the TIGHAR mailing
> list
> > too).
> >
> > But after reading "Amelia Earhart: The Mystery Solved" I have to
> concur
> > with the author's conclusion that after all of those long hours
> from
> > Lae (New Guinea) they were nowhere near where they thought they
> were
> > (probably different winds aloft than they'd counted on), ran out of
> > fuel, and had to ditch at sea.
> >
> > Even more mind-boggling (at least in 20/20 hindsight) is that
> they'd
> > try to locate the tiny Howland Island just on DR/celestial alone
> > (neither of them apparently knew how to work the radio
> > direction-finder), and if I remember right they also weren't able
> to
> > communicate with the Itasca on the frequencies that they'd planned
> on
> > (seems like they either didn't have voice or CW capability, I don't
> > remember exactly right now).
> >
> > What's your "pet theory" on the Earhart mystery?
> >
> > --
> > GregR
> >
> > --- glap...@pacbell.net wrote:
> >
> > > Here are excerpts from the 1937 N.A The first page shows the time
> of
> > > transit of the moon of the Greenwich meridian and contains a
> "Var.
> > > per hour" column, variation?
> >
> > >http://www.geocities.com/fredienoonan/almanac-1937-136.JPG
> >
> > > The second page contains moon data showing GHA and DEC and has
> > > separate increments tables for each day based on the the dec
> change
> > > and GHA change rates for that particular day. no "v" or "d"
> > > correction factors are shown.
> >
> > >http://www.geocities.com/fredienoonan/almanac.html
> >
> > > This third link takes you to a site I put up with with excerpts
> of
> > > various navigation texts.
> >
> > >http://www.geocities.com/fredienoonan/
> >
> > > gl
> >
> > > On Jun 19, 9:00 pm, frankr...@HistoricalAtlas.net wrote:
> > > > Greg, you asked:
> > > > "And maybe that's going to be about as good an answer as we can
> > > hope for
> > > > at this point in time - does anyone know when "d" and "v" terms
> > > first
> > > > showed up in the NA as such? There might be more elaboration
> about
> > > what
> > > > the abbreviations stood for when they were first introduced."
> >
> > > > Yes, that's basically what I was providing you in the previous
> > > message. The
> > > > labels "v" and "d" first appear in the "Abridged Nautical
> Almanac"
> > > in 1952.
> > > > This is the earliest date when the official British almanac
> > > included GHA.
> > > > This had been introduced 18 years earlier in the American
> Nautical
> > > Almanac,
> > > > and it was also widely used in the various air almanacs. As I
> said,
> > > the
> > > > concept of the interpolation constant at the foot of each
> column on
> > > the
> > > > almanac page was already present in the American almanac where
> it
> > > was called
> > > > a "code". I also checked a couple of commercial British
> almanacs
> > > from this
> > > > period (the commercial British almanacs adopted GHA well before
> the
> > > official
> > > > British almanac). They use a similar principle but again not
> > > labeled v and
> > > > d. So my best guess right now is that the first use of these
> > > specific labels
> > > > for the interpolation data is the British "Abridged Nautical
> > > Almanac" in
> > > > 1952. Here's the full text from the explanation in the AbNA for
> > > 1953:
> > > >  "Interpolation between the tabulated hourly values is provided
> for
> > > by
> > > > comprehensive interpolation tables, printed on coloured pages
> at
> > > the end of
> > > > the book, giving for every minute and every second the
> increments
> > > of G.H.A.
> > > > corresponding to the mean rate of increase for the Sun (15�
> > > precisely), the
> > > > constant rate for Aries (15� 02'.46) and the minimum rate for
> the
> > > Moon (14�
> > > > 19'.0). The variations from the means are so small for the Sun
> that
> > > they
> > > > have been deliberately ignored; the tabulated hourly values of
> the
> > > Sun's
> > > > G.H.A. have been adjusted so that the error thus caused is a
> > > minimum. These
> > > > variations cannot be ignored for the planets or for the Moon,
> and
> > > > corrections have to be made for the excess (v) in hourly motion
> > > over that
> > > > adopted in the main interpolation tables."
> >
> > > > So there's an answer: v stands for "excess". :-)
> >
> > > > In the next paragraph:
> > > > "The corrections for these VARIATIONS [...] are taken directly
> from
> > > the
> > > > interpolation tables with argument v" and "A similar procedure
> is
> > > used to
> > > > interpolate the declinations of the Sun, Moon and planets; here
> d,
> > > the
> > > > hourly DIFFERENCE, is given without sign on the daily pages" (I
> > > have
> > > > capitalized those two words for emphasis). So if you must
> assign a
> > > meaning
> > > > to v and d, I think the best bets are "variation" (of the rate
> of
> > > change of
> > > > GHA from the selected mean rate) and "difference," but the
> catch is
> > > that the
> > > > person who wrote this explanatory section may very well have
> > > invented those
> > > > origins on the spot.
> >
> > > > By 1958, when the modern Nautical Almanac was formed by the
> merger
> > > of the
> > > > American Nautical Almanac and the Abridged Nautical Almanac
> (they
> > > kept their
> > > > separate names until 1960), the explanation simply refers to v
> and
> > > d values
> > > > with no hint of any etymology. Same in Bowditch of the same
> era. I
> > > think
> > > > this is intentional. The labels v and d really are not intended
> to
> > > "stand
> > > > for" anything.
> >
> > > >  -FER
> > 
> 


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