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No, I found those pictures on line in a story by a man who flew his
plane to Lord Howe from Australia.. But, from the pictures, i would
like to visit that island some day.

gl

On Aug 5, 8:59�pm, "Christian Scheele"  wrote:
> Gary,
>
> in the interest of the much invoked respect for threading I am starting a
> new thread in which I respond to your message below. I'm calling this thread
> "Single-body fix", though I fear that a few of the experts who have written
> profusely on precisely this subject (yourself not included) may not be
> amused by my dabbling in this area...
>
> By "single body fix method", I was referring to the method whereby the rate
> of change of a celestial body's altitude is used to fix one's position, but
> your message was most relevant and I would appreciate it if I could get back
> to you on the Polaris latitude shot in another message.
>
> Thanks for attaching "Seaplane Solo" to one of your posts, my Chichester
> collection is nearing completion. A few of the aerial photos of
> Lord Howe appear to have been made from a fixed-wing aircraft. Were you the
> pilot on this flight?
>
> Christian Scheele
>
> ----- Original Message -----
> From: "Gary LaPook" 
> To: 
> Sent: Monday, August 03, 2009 7:14 PM
> Subject: [NavList 9313] Re: Bygrave and Chichester
>
> By "single body fix method" I take it you are talking about the recent
> thread about taking many sights of the sun around noon and finding both
> latitude and longitude from these sights. I have never seen anything
> about using this method in flight by anybody. Although it is
> theoretically possible to do a conventional noon sight for latitude in
> flight it is extremely difficult due to the speed of the plane which
> masks the point of actual noon. But, more importantly, there is no
> particular advantage in attempting to do so. The traditional noon sight
> only made sense in the olden days when it was onerous to do the trig for
> a Sumner line �LOP and the noon sun sight had much simpler computation,
> just addition and subtraction. By the time of in fight celnav there was
> a plethora of tables (Dreisenstock, Ageton, Weems, Hughes) and, of
> course, the Bygrave slide rule that made the trig trivial so there was
> no reason to go through the contortions of trying to use the special
> case of a noon sun sight.
>
> I did notice, however, while analyzing Fred Noonan's chart work on the
> Earhart flight in 1937 that he continued to utilize the special case of
> the Polaris shot. This also continued to be used by �Air Force
> navigators since it is extremely simple and doesn't suffer the problems
> inherent with the noon sight. You use the "Q" correction table from the
> Air Almanac or from H.O 249, �not to determine latitude but to do a
> simplified calculation of computed altitude for Polaris and then treat
> the Polaris line as any other LOP advancing it as with any other LOP to
> determine a fix. The "Q" table is a simplified table that accomplishes
> the same thing as the Polaris tables in the Nautical Almanac to a lower
> level of precision. Using the "Q" table you enter the table with the
> local angle of Aires and then apply the correction with sign reversed to
> calculate computed altitude, compare it with observed altitude to
> determine intercept. The azimuth is also found from these tables and can
> vary from 358 � �to 002�.
>
> An example should help. If Polaris was actually at declination 90 �
> north then the altitude measured with the sextant would equal your
> latitude. So using the simple case when Polaris is directly east or west
> of the pole the altitude measured is also equal to your latitude and the
> "Q" correction is also zero. So using the mariner's method you measure
> an altitude of 35 � 30' so you determine that your latitude is also 35 �
> 30' north. But the way a flight navigator would do it is he would assume
> a position for finding a fix using Polaris and other stars, say 35 � 00'
> north and compute an altitude for that AP of 35 � 00'. Then he compares
> his Ho of 35 � 30' and determines his intercept of 30 nm toward Polaris.
> This line would also plot at 35 �30' north, assuming that it had not
> been advanced to cross the other LOPs to find the fix. Since the actual
> azimuth of Polaris is used this line may be slightly more accurate than
> when using the mariner's method.
>
> gl
>
> Christian Scheele wrote: to determine
> > �I recommend this
>
> >> book, Seaplane Solo, to everybody and I can email a copy to anyone who
> >> is interested.
>
> > I would much appreciate a copy, Gary.
>
> > I am not starting a new thread because the subject is related to your
> > commentary on the difficulties of making celestial observations. Could you
> > give me a reference to anything on the attempts by Byrd and Weems to use
> > the
> > single-body fix �method by taking sun shots through the open hatch of
> > their
> > seaplane?
>
> > Christian Scheele
>
> > ----- Original Message -----
> > From: "Gary LaPook" 
> > To: 
> > Sent: Saturday, August 01, 2009 3:59 AM
> > Subject: [NavList 9281] Bygrave and Chichester
>
> >> My interest in the Bygrave was triggered by my reading Sir Francis
> >> Chichester's account of flying a Moth, open cockpit single engine
> >> airplane across the Tasman Sea in 1931 doing celnav on the way to find
> >> two tiny islands where he could refuel, each leg about 500 nautical
> >> miles. Today, at Headcorn Aerodrome in England, I had the opportunity to
> >> fly the same type of aircraft and my admiration for Chichester increased
> >> ten fold. It is a very light aircraft so it is bounced around a lot my
> >> even the lightest turbulence. The controls are very sensitive,
> >> especially in pitch, so it takes a lot of concentration to keep the
> >> plane flying straight and level. It is also very noisy and the wind
> >> blows vigorously through the cockpit. I don't know how Chichester
> >> managed to do it, flying the plane, shooting sun lines with �a marine
> >> sextant, doing the computations with the Bygrave (holding it
> >> horizontally so it didn't get blown out of the cockpit), estimating
> >> drift angle, and plotting the LOPs and the drift lines. I recommend this
> >> book, Seaplane Solo, to everybody and I can email a copy to anyone who
> >> is interested.
>
> >> gl
>
>
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