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Hi all,

I have been sulking in the background on the subject of averaging and 
analyzing individual sights to the extent spoken of on this list, however, as 
Jeremy has now spoken up, I will add my two cents worth.

In my long past experience, USMM, USN, and USCG, I have seldom, if ever, 
witnessed the averaging of routine individual sights, or even heard the 
subject spoken of, except in textbooks. As Jeremy indicates, the duties of a 
MM watch officer, or for that matter any MM officer, are such as to preclude 
the time for repetitious sights or analysis. This statement may not hold true 
for the USN or USCG, where there may have been sufficient manning to afford 
the luxury of a dedicated "Navigator", although on smaller ships this 
responsibility was often a collateral duty - still the averaging of sights 
was certainly not general practice, if at all practiced.

Certainly it was true that, under adverse conditions where routine sights 
might not be available, to take multiple sights of an individual single body 
as it might come into fleeting view, if nothing else was available, and then 
to work each sight individually in an evaluation of potential error induced 
by changing horizon conditions, necessary haste in observing, or other 
influencing factors. However, in such circumstances, if appropriate, the RDF 
would have been manned, the fathometer operating, and an armed deep sea lead 
in use. I am of course speaking of days before Loran, Decca, SatNav, Radar 
and, in some circumstances a Gyro Compass, etc.

Regards,

Henry


--- On Sun, 8/10/08, Anabasis75@aol.com  wrote:

> From: Anabasis75@aol.com 
> Subject: [NavList 6096] Re: R: [NavList /] Re: Exercise #14 Multi-Moon LOP's
> To: NavList@fer3.com
> Date: Sunday, August 10, 2008, 11:43 AM
> I would like to see some of the problems.  I am sure my
> computer  program can
> go back that many years.
>
> As you can see with my exercise posts, I was entertaining
> the list group
> with some sight from sea, ranging from the simple to the
> fairly exotic.   Once I
> return to sea in October, I will add more exercises to the
> list.
>
> It is not common practice in the US Merchant Marine to take
> and average  more
> then 3 sights in my experience, and to be honest, I have
> only very rarely
> seen any sights averaged, and those were always sun lines.
> I have heard  tell
> of Captains taking a round of stars in one set, then
> shooting the same  stars
> sometime later in the same twilight, but have never seen
> this in practice,
> even on the training ships.
>
> For this reason, I find it interesting all of this talk
> about finding  slopes
> and speaking of probability mathematics, when the subject
> is not even in  the
> curriculum of a Deck officer college course.  Frankly, the
> deck officer
> hardly has the time to shoot a round of stars and reduce
> them on the computer
> among his myriad of other duties, let alone spend the time
> shooting a body
> multiple times and then finding slope lines.  I am
> permitted to shoot stars  only
> when there is no traffic or I am not on watch, even then, i
> feel the loss  of
> situational awareness.  This is why you see my multi-shots
> done in a  matter of
> minutes and they are reduced later in my stateroom.
>
> Jeremy
>
>
> In a message dated 8/9/2008 7:55:41 P.M. Eastern Daylight
> Time,
> fedeastro.rossi@libero.it writes:
>
>
> Jeremy,
> you're right, what I got is only an estimated position,
>  which is meaningless
> unless the 1900 ZT position is considered a DR  position as
> it used to happen
> before GPS.
> I still have some navigation  notes that my father took
> when he was an
> Italian merchant marine deck  officer. They are real life
> celnav problems and
> if anyone is interested I  would be glad to post some of
> them  here.
> Federico
>
>
>
>
>
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> fits in your budget?
> Read reviews on AOL Autos.
> (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017
> )
>
>



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