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--- "Gary J. LaPook"  wrote:

> BTW, did you ever check my work?

I posted the solution to that one in [NavList 5428]: "GPS position for
that series of sights is 34�14.4�N / 119�15.9�W, and my Navigator
computer program calculates 34�12.6'N / 119�16.5'W (using APs of 34�N
and W longitudes to give a whole number of LHA)".

Or, if you'd like to me take a look at the (creative) method you used
to solve it post a message # and I'll take a look at it.

--
GregR



--- "Gary J. LaPook"  wrote:

> BTW, did you ever check my work?
> 
> gl
> 
> Greg R. wrote:
> 
> Assuming you're not being tongue-in-cheek with your solution (and
> being
> at work I can't verify it right now), regardless of accuracy you
> definitely get the Most Unique Solution award (plus an honorary
> Navigator Who I'd Most Want To be Shipwrecked With plaque, with gold
> clusters).  :-)
> 
> 
> >Heh... I almost wrote the exercise with all of the navigation books
> >being lost overboard too, and luckily the intrepid navigator had
> >memorized their entire contents - but figured that was a bit too
> much
> >of a stretch. Now I may have to re-consider that option...  ;-)
> >
> >Assuming you're not being tongue-in-cheek with your solution (and
> being
> >at work I can't verify it right now), regardless of accuracy you
> >definitely get the Most Unique Solution award (plus an honorary
> >Navigator Who I'd Most Want To be Shipwrecked With plaque, with gold
> >clusters).  :-)
> >
> >--
> >GregR
> >
> >
> >
> >--- "Gary J. LaPook"  wrote:
> >
> >  
> >
> >>Being the conscientious navigator that I am, I followed my usual 
> >>practice of memorizing some data from the 2008 Nautical Almanac so
> >>that 
> >>I would have it available for emergency use.
> >>
> >>The first thing I memorized was the GHA of Aires at 0000 Z January
> 1,
> >>
> >>2008 which is 100� 01.9' and also remembering that Aires advances 
> >>59.139' each day. With this information you can calculate GHA Aires
> >>for 
> >>0000 Z on June 9, 2008 which is the 161st day of the year but is
> only
> >>
> >>160 days from January 1st. So multiplying 59.139' times 160 days
> >>gives  
> >>157� 42.2'  to which you add the starting value of 100� 01.9' to
> come
> >>up 
> >>with the GHA Aires on June 9th at 0000 Z of  257� 44.1'. To this
> you
> >>add 
> >>the change of GHA for the time since 0000 Z (3 hours 42 minutes 10 
> >>seconds for the Vega shot) by multiplying the time interval by the
> >>rate 
> >>of change of 15.041� per hour making 55� 41.6' making the GHA Aires
> >>at 
> >>the time of the Vega shot of 313 � 25.7'.
> >>
> >>I also memorized the SHAs and the Declinations of ten of the
> >>navigation 
> >>stars ( nobody could memorize all 57) which should be enough for 
> >>emergency use as tabulated for July 1st so that the values will be 
> >>reasonable for the whole year. Fortunately this included the three
> >>stars 
> >>used in this exercise. So now adding the SHA of Vega, 80�  41' we
> end
> >>up 
> >>with the GHA of Vega of 34� 06.7' and using the D.R. as the A.P. we
> >>get 
> >>an LHA of 274� 48' and the declination of 38� 47' N. (rounded to
> the 
> >>whole minute)
> >>
> >>Using these values on my Bygrave slide rule (see attached work
> sheet)
> >>
> >>since I have no tables with me, I computed Hc of 23� 59'.
> >>
> >>The Hs given was 24� 05.5' Computing the dip correction in my head
> of
> >>
> >>4.5' (the square root of 20 must be between 4 and 5 ) and applying
> >>the 
> >>refraction correction of minus 2 gives an Ho of 23� 59' giving and 
> >>intercept of zero and an azimuth of  58.1 �.  I long ago memorized
> >>the 
> >>refraction table for altitudes above 10� in The Air Almanac and in
> >>H.O 
> >>249, the cutoff values are 63-33-21-16-12-10� , zero above 63, 1
> >>above 
> >>33, 2 above 21, 3 above 16, 4 above 12 and 5 above 10.
> >>
> >>I used the same procedure for Spica and Pollux getting another zero
> 
> >>intercept for Pollux, Zn of 290.2� and a  4 NM away for Spica with
> a
> >>Zn 
> >>of 171.7�.
> >>
> >>Since I am on the road I do not have any of my plotting tools with
> me
> >>so 
> >>I had to make do with what I found in my briefcase. I used my MB-2A
> 
> >>flight computer since it had an azimuth scale and I used a pad of
> >>paper  
> >>with a right angle at the corner as my straight edge for plotting
> the
> >>
> >>LOPs. I used a tape measure from IKEA to measure the length of the 
> >>intercept (see photo.)  I plotted the LOPs and found the fix by 
> >>bisecting the three angles giving a fix .4 NM west of the A.P.
> (D.R.)
> >>
> >>and 2.8 NM north of it. (Plotting a fix as a distance from the A.P.
> >>like 
> >>this is common in aerial practice and it is often done on an E-6B.)
> 
> >>Adding the 2.8 NM north to the D.R. latitude gives a fix latitude
> of
> >>34� 
> >>16' North. To convert the .4 NM west  to a longitude you divide the
> >>.4 
> >>NM by the cosine of the latitude, .82, to find the difference in 
> >>longitude of  .5' so the fix longitude is 119� 19.5' West (rounded
> to
> >>
> >>either 119� 19' or 20'.)  ( I got the cosine of 34� by finding the
> >>sine 
> >>of 56� on the MB-2A sine scale, used for wind correction
> >>calculations.)
> >>
> >>My fix might not be in agreement with others but I used a
> refraction 
> >>table tabulated in whole minutes, I only memorized the stars'
> >>positions 
> >>to the nearest minute and I did not have any plotting tools to use
> >>but 
> >>my position is certainly good enough for emergency navigation and
> >>done 
> >>without an almanac, tables or electrons.
> >>
> >>(I will have to send the images when Ii figure out how to make them
> 
> >>smaller.)
> >>
> >>gl
> >>1
> >>
> >>m_burkes@msn.com wrote:
> >>
> >>    
> >>
> >>>Captain Lecky would be proud of those dividers ha! Speaking of
> >>>interpolation I have found a neat way to get around that pesky DSD
> >>>      
> >>>
> >>and
> >>    
> >>
> >>>interpolation tables by using the aviation E6B computer or the
> >>>equivalent nautical slide rule. Essentially the set
> up:d-value/60=d-
> >>>correction/declination minutes. Yes the calculator offers the
> proof.
> >>>Mike Burkes
> >>>On Jun 12, 11:44 pm, Anabasi...@aol.com wrote:
> >>> 
> >>>
> >>>      
> >>>
> >>>>Thanks for the nice exercise Greg.  I literally had to dust off
> the
> >>>>        
> >>>>
> >> ship's
> >>    
> >>
> >>>>Vol III of HO 229 and deflower a Plotting sheet 925 to work this
> >>>>        
> >>>>
> >>one  out.
> >>    
> >>
> >>>>Since I was bereft of electronic gadgets, I did this with a
> >>>>        
> >>>>
> >>plotting sheet,  
> >>    
> >>
> >>>>2 triangles, a pair of dividers, 2 books, a pencil, and small
> piece
> >>>>        
> >>>>
> >>of scratch
> >>    
> >>
> >>>>paper (wouldn't have reams of paper in the Lifeboat).  I have
> >>>>        
> >>>>
> >>attached a  
> >>    
> >>
> >>>>picture in to this message with the plot and the tools.
> >>>>
> >>>>My Lat is a bit lower (plotting or math error?).  I used an
> assumed
> >>>>        
> >>>>
> >> position
> >>    
> >>
> >>>>method and HO 229.  I had to assume we were drifting and no 
> >>>>        
> >>>>
> >>current (didn't
> >>    
> >>
> >>>>advance or retard the lines).  I had not done a full HO 229 
> paper
> >>>>        
> >>>>
> >>reduction
> >>    
> >>
> >>>>of a star in many years, and I had to think a second to remember 
> >>>>        
> >>>>
> >>how to use
> >>    
> >>
> >>>>the interpolation pages on the inside covers for the declination 
> >>>>        
> >>>>
> >>interpolation.
> >>    
> >>
> >>>>I usually whip those off with the calculator.  Still,  I got
> >>>>        
> >>>>
> >>pretty close to
> >>    
> >>
> >>>>the computer solutions with Lat 34deg 11.9' N and  Longitude
> 119deg
> >>>>        
> >>>>
> >>16.0'W.
> >>    
> >>
> >>>>As to how you would get an Eastern sight on the west coast, you
> >>>>        
> >>>>
> >>would have  2
> >>    
> >>
> >>>>options in general.  The first would be a back sight.  This would
> >>>>        
> >>>>
> >>be  
> >>    
> >>
> >>>>particularly difficult with a regular sextant at such a low
> >>>>        
> >>>>
> >>altitude.  The  other
> >>    
> >>
> >>>>option would be to use a bubble sight tube or other artificial 
> >>>>        
> >>>>
> >>horizon.  If you
> >>    
> >>
> >>>>were across a bay, you could also use a dip short of  the horizon
> >>>>        
> >>>>
> >>table.  
> >>    
> >>
> >>>>That's all I can think of at the moment.
> >>>>
> >>>>Jeremy
> >>>>
> >>>>**************Vote for your city's best dining and nightlife.
> >>>>        
> >>>>
> >>City's Best
> >>    
> >>
> >>>>2008.      (http://citysbest.aol.com?ncid=aolacg00050000000102)
> >>>>
> >>>>gregExerPlot.jpg.JPG
> >>>>182KViewDownload
> >>>>
> >>>>GregExerTools.jpg.JPG
> >>>>129KViewDownload
> >>>>   
> >>>>
> >>>>
> >>>>        
> >>>>
> >>> 
> >>>
> >>>      
> >>>
> >>    
> >>
> >
> >
> >>
> >
> >  
> >
> 
> 
> > 
> 


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