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I know nothing about navigation, but I doffs me cap to those who do. Reason I am saying this is, after reading these posts, and remembering the worst storm I was ever in, I marveled at the the mates who got us to Canada having been shoved, washed, and nearly pushed ashore into Sable Island, then having the same treatment back to the UK.
Des
Des at 15 I had to go to a nautical School to learn the world is not round. That’s the first thing you should learn.
Maybe today they still teach ashore that it is round. Got anyone who has allusions that it is then they are under an allusion,
“ The earth is an elliptical shape with its polar diameter 27 nautical miles less than its equatorial diameter,
And from there one progresses into plane and celestial geometry.
And geometry was something I did not excel at when a scholar.
But Trigonometry, that is a different subject.
The square on the hypotenuse is equal to the sum of the square on the other two sides of a triangle.
I also struggled with simultaneous equations.
But did well with knot tying in the Scouts
#13 John celestial trigonometry is slightly different to the school plane trigonometry that you learned at school. E.g.there are 3 angles in a triangle with a total of 180 degrees .In a celestial triangle you could have between 360 and 540 degrees .work that one out ? Don’t ask me I only remember that statement being made to me in the far distances of time. I never had to prove it , so maybe someone else can. Cheers JS
Don't think I could prove it now John, but it is amazing how one word brings back to life, things we had forgotten we knew, sometimes of no relevance whatsoever in today's world, but vitally important in our past lives.
Oh! Michiko!:dream:
Like all Sausages Turn Cold Ivan ? JS
Think today the student would have trouble with that one as need an old penny to draw the circle !! JS
When one thinks back the old coins of the Realm had other uses apart from beer and Baccy.
E.g. as said the diagram for all sausages turn cold. For drawing the facial part and quadrants of a TRS.
And even to assist in childbirth for measuring the apertures in the birth canal in ref to the size of certain British coins.
We lost a lot when we went decimalisation.
Cheers JS
Could you still work out morning sights the old way by hand ?. Nories tables and the nautical almanak ?. I know I couldn't any more. Things like right ascension and hour angle are now just a very distant memory .Quote:
Originally Posted by j.sabourn
Yes John believe I could, either Longitude by Chronometer or the intercept method Mark St. Hilaire.
Haversine ZX = Haversine LHA Cos Lat Cos Dec + ( hav lat difference Dec. ) .if doing a running fix with the sun
The correction to apply to your estimated longitude at noon was the difference between the true latitude and the estimated latitude x your C correction applied toward the sun or away from to,apply to your longitude it depending on your intercept and your azimuth of the sun. None of this plotting position lined on the back of the chart as taught at school.If you wanted to be neat and tidy another use of the farthing could be used to represent the sun in the margin of your paper or sight book as the case may be.with the azimuth and I must admit though taken stars position line as a reminder for your own convenience. It was my bread and butter for a lot of years.Cheers
I must admit however with 5 stars I did plot them and just picked out the centre of the big cocked hat and the mean time of shooting such .JS.
PS in case you have forgotten a Haversine was half a Versine and a versine was 1minus Cosine Theta.JS…..
One thing I have learned from life one keeps on learning, I left school a complete dunce, but with the help of my wife I have reached great heights LoL. She helped me through my carpentry course.
A game on TV , Letters and numbers is on every night , I am now so quick at working out maths answers I sometimes beat my wife at it, why couldn't I do that at school?
But it just shows how one can slip. Last night on a game on TV called Tipping point from the UK, a two year retired MN Captain was up against a young girl, the question, "what is the name of the island opposite the Straits of Messina and Italy?" His answer was Turkey?
Des
He must of had Xmas on his mind Des ? JS