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Jackie,
A compass does not need a sighting device (unless you are traveling
overland, and want to keep on a straight course). It could have been
a compass repeater for convenience at the nav station. There is also
an instrument called an Astrocompass which is used only in polar
regions, and therefore not applicable on this flight.  The
Astrocompass is aligned by sighting on the tail of the airplane. A
driftmeter would have to be aligned on the ground by looking at
ground markings with respect to the airplane's orientation. A
driftmeter is crucial to the type of flight discussed, and would have
been used by Noonan frequently.  In looking through a driftmeter, one
sees a moveable grid which one aligns to the direction the waves,
whitecaps, or ground features move, and thus obtains the drift angle
of the airplane with respect to it's heading.  By timing the passage
of features, the navigator can also obtain the ground speed of the
airplane.  Both values are necessary to compute an accurate DR for
the airplane.

Ken
On Oct 28, 2009, at 2:36 PM, Jackie Ferrari wrote:

>
> Ken,
>
> The caption under the photo of the pelorus in Mary Lovell's book
> says it was
> a sighting device for the compass. I also read someplace that one
> method of
> measuring drift was to sight on the tailplane. Do these sound
> feasible? I
> understood that he had a drift indicator which was used by mounting
> it on a
> bracket through the slightly open door??  Has anyone heard of this
> method?
>
> Jackie
>
>
> ----- Original Message -----
> From: "Ken Gebhart" 
> To: 
> Sent: Wednesday, October 28, 2009 3:32 AM
> Subject: [NavList 10290] Re: Amelia Earhart's aerial navigation
>
>
>>
>> Just chiming in.  I cannot think of any possible use a pelorus would
>> have on an airplane.  A drift Sight would be critical, but not a
>> pelorus.
>>
>> Ken Gebhart
>> On Oct 27, 2009, at 8:45 PM,  wrote:
>>
>>>
>>> Jackie, you wrote:
>>> "One of the few things we know for sure is there was a pelorus
>>> fitted on a bracket at the starboard window which I understood him
>>> to have used to take bearings. This is shown in several
>>> photographs."
>>>
>>> Can anyone point me to one of these photos somewhere online? I
>>> tried to find one. Based on the text descriptions I've found of the
>>> gear in the navigator's station on the Electra, I would now guess
>>> that the current film got the details exactly correct visually.
>>>
>>> And you wrote:
>>> "I havent seen the film yet, but I have heard it pays scant
>>> attention to Noonan. But at least this time round they get the
>>> resemblance right. Apparently he is portayed as unintelligent and
>>> boisterous. Quite the opposite. He was highly intelligent and quiet
>>> spoken."
>>>
>>> I wouldn't say that he's portrayed as 'unintelligent' --it's just
>>> that his character is barely fleshed out --"scant attention" just
>>> as you say. As for being 'boisterous', the rumors of drinking come
>>> up early and there's a speculative scene where he very mildly hits
>>> on Earhart while drinking the night before the last flight. He (the
>>> character) apologizes the next morning and all is forgiven and
>>> forgotten. Though that's all pure speculation, it wouldn't surprise
>>> me if the issue had arisen at some point during the circum-
>>> navigation given Earhart's well-known extra-marital activities and
>>> given the amount of time they spent together. Like I say, it's not
>>> played in the film as salacious gossip. It simply calls attention
>>> to something that every viewer has to be thinking.
>>>
>>> I think the square door I thought I saw, and mentioned previously,
>>> was a perspective trick. I checked the trailers online, hoping for
>>> a shot of Noonan's navigation station with the pelorus, and saw a
>>> different angle on the door --not square.
>>>
>>> -FER
>>>
>>>
>>>
>>>>
>>
>>
>>>
>
>
>

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