VO5
Well-Known Member
i am a little bit confused, with all my respect, to mr VO5, attitude !
for the simple use of sextant, the mr VO5, contribute almost 20 posts and everyone which have tried to help the others, how to use, this old method of position fixing, was .........!
i have one very simple question to mr VO5, in case some boatowners are on short budget, like me, how they can learn and practice the sextant if they can not fulfill below requirement
qte
You need to have the complete kit for it which is:~
A really good sextant, preferably fitted with light to read the arc.
Two mechanical stop watches for day use.
Two luminous stop watches for night use.
A chronometer. Mechanical or Elrectronic.
A copy of Nories or Burtons.
The Admiralty Almanack for the current year.
Foolscap paper.
unqte
i am not against to have the best one from the market but this do not help the others !
know, how to use, and how the stuff work is more important for me!
ok, i dont have a high cost sextant but cheap one without the light to read the arc
(one hint for you - i can find the sextant error)
i dont have Two mechanical stop watches for day use.
i dont have Two luminous stop watches for night use.
i dont have A chronometer. Mechanical or Elrectronic.
i dont have A copy of Nories or Burtons.
i have only radio, wristwatch, almanach for the current year & sight reduction tables ! and one more very important item - star finder))))
if we are in the middle of the atlantic, i bet, that the mr. VO5, with all the above fancy things, can not find his position, using the sextant for star observation, because, he forgot that he need to identify the stars before to commence!
without the stars, there is no position fix !
just to explain - the stars, are usually worked before sunrise and after sunset or at the time, when the dark or the lights are comming, the time is very short and if the stars for observation are not pre-scheduled by azimut and altitude, the work is impposible !
for all those that like to learn something for using the sextant, please have a look on my first posting - this is how to use the sight reduction tables for marine navigation !
have a look at introduction - a lot of usefull stuff!
beware of the sight reduction tables for air navigation - you can use these tables also but they are for time of 5 years if i am not wrong!
additional to the tables, one need to know, how to use the almanah, to identify the sextant error, correction of the observed altitude and how to add and substruct!
just try to convince everyone - this is not a difficult stuff to learn !
with best regards
www.neatcss.com
Of course it is not difficult to learn.....IF.....(which is the smallest word in the English Language but possibly the most importasnt)...if..it is taught properly.
You would have learnt, if you had gone to navy college, to identify a handful of stars suitable for observation at night, you would have been taught how to spot them, even through gaps in clouds.
You would have learnt how to calculate the approximate sextant angle in advance of shooting them and roughly which direction they would lie in.
You would have been made to become familiar with star maps, not necessarily all of the major 57 navigational stars and all the planets but at least for you to have a workable menu.
Therefore my dear fellow Mr VO5 in the middle of the Atlantic, or in any other part of the world for that matter, would not have this problem as he carries a picture of the major navigational stars which are easily recogniseable not on a map but in his head, so therefore you are thanked for your concern but you would have lost your bet.
If you do not wish to acquire all the kit I list which is the "classical" requirement or as you may wish to call it, there are other alternatives.
I read a very interesting account of a young man who crossed the Pacific single handed without a sextant or a chronometer or even stop watches but by using a star map for the southern hemisphere and a length of string with a weight at the end.
He would lie on his back in his boat at night and identify which star was in his zenith and from this calculate his latitude. As he was sailing west to east all he did was keep going until he reached land. This article was published in a major British yachting magazine of several years ago, but I do not recall which one.
Actually sailing east or west without a sextant (except to observe the altitude of Polaris) is not difficult. The difficulty arises if the course is anything but 270 - 090. This is because longitude cannot be calculated with a sextantalone, (as the users of the backstaff, and the octant, the grandaddy of the sextant already knew).... but it can with the use of a chronometer, using an almanack.
This is why the Board of Longitude offered a prize of £16,000 to whosoever could solve the problem of finding Longitude at sea, and it was won by Harrison, who invented a timepiece of sufficient accuracy to be able to fulfil the criteria including that of an even rate (of loss or gain).
The Sextant error is a different topic and deserves a chapter all of its own.
I presume you are talking of errors relating to the arc itself and not the other ones.
Errors on the arc.
The rule is, if its on, its off
and if its off its on.
Meaning, if the error is on the arc, subtract to get a corrected reading.
If the error is off the arc, then add to obtain a corrected reading.
For horizontasl bearings no corrections are necessary.
When observing the sun, do not forget to put in place the shades first !
Do not manhandle the sextant by picking it up by the index arm !
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