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Old 09-11-2019, 19:59   #61
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Re: Are antique sextants any good?

i was too busy reading your little side pieces on Cramer...
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Old 09-11-2019, 21:40   #62
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Re: Are antique sextants any good?

An actual antique sextant would not necessarily be so bad. The problem is most of the offerings on a certain auction website listed as as "antique sextant", in that price category, are neither antique, nor actual sextants meant to be used for navigation.
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Old 10-11-2019, 08:00   #63
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Re: Are antique sextants any good?

There are a lot of sailors looking for a navigation plan B, even the Navy! They are reinstating celestial. I am not second guessing the OP but I assume that is his intent.

I'll drop the Cramer diversion to spare you from undermining his great achievent.

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Originally Posted by charliehows View Post
...

I kind of doubt whether someone asking about buying an antique sextant for $100 is actually ever going to be in a situation where the use of the instrument for a position fix is either necessary or possible; but even if it were so, the level of reliability and accuracy of a $100 handheld GPS is, at least for the present, about 1000 times better than any position derived by sextant (antique or no), chronometer and almanac.
Assuming you have a funtional device(s). Just saying.
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Old 10-11-2019, 08:14   #64
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Re: Are antique sextants any good?

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If a plastic one is going for $300 or so, an Astra is well worth the $650. They are Chinese but the reviews have been very good and they are a robust and well made instrument.
I hear the Chinese have a merchant marine fleet and perhaps one or two freighters sailing the seas, so perhaps they have professional quality equipment as well

I think the OP might check out Alibaba or any of the major equipment manufacturers and for $400-500 get an actual professional model, instead of a learner's plastic model.
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Old 10-11-2019, 08:53   #65
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Re: Are antique sextants any good?

Swinging back to the OPs question: Are antique sextants any good?

1) there's nothing wrong with a used REAL sextant, as long as it's complete and not damaged

2) the majority of items labelled "antique sextant" on ebay are simply ornamental reproductions. Nice, yachty paperweight for your office desk or den... Aboard a boat, they could be used to jam a door open, or similar.

As the owner of a plastic sextant... it's been sufficient to learn on and the $150 I paid was less painful than $500+. Of course, my sextant is now selling for $250 (ouch), so maybe the Chinese "real" sextants are becoming the better value.
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Old 10-11-2019, 13:01   #66
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Re: Are antique sextants any good?

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Assuming you have a funtional device(s). Just saying.

Assuming you have a functional chronometer, a functional sextant, an up-to-date almanac and a decent set of maps. Just saying.
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Old 10-11-2019, 13:10   #67
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Re: Are antique sextants any good?

Actually you can get by without the chronometer.
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Old 10-11-2019, 13:11   #68
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Re: Are antique sextants any good?

Considering the state of turmoil in the wold today and the ongoing development of cyber warfare, it might be a good idea to learn a form of navigation not dependent on electronic inputs from God knows where. Let's remember that those inputs can be turned off at any time, or even falsified to the point where they put you on a reef.
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Old 10-11-2019, 13:51   #69
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Re: Are antique sextants any good?

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Assuming you have a functional chronometer, a functional sextant, an up-to-date almanac and a decent set of maps. Just saying.

A $15 digital wristwatch will do for a chro. You still have to rate it, of course. In the absence of radio time ticks or satellite data, you would need to once in a while do a time check by obviously passing a point of known longitude, or taking a lunar, or some other means of longitude or time verification.



It is fairly simple to use last year's almanac for taking sun lines. Accuracy is reduced but still probably better than the observer's accuracy. Further, there are tables for solar long term data that can be used in a pinch.



Set of maps? You can create a plot sheet for your latitude using a compass and a protractor on a sheet of paper. And old, out of date charts work fine for plotting your position. They simply do not tell you what hydrographic data and features have changed in the interim. Once you are at large scale charts, you are probably in sight of land anyway, and using pilotage rather than navigation.


A catastrophic failure of electronic navigation systems is unlikely but possible. A catastrophic failure of celestial navigation methods simply is not possible. Your sextant cannot simply stop working. If your watch stops working, you still can figure your latitude and keep a DR, which is THE SINGLE MOST IMPORTANT part of a navigator's toolset.



Electronic navigation has a lot of advantages over celestial in normal everyday usage. The biggest disadvantage is that it is so simple that many boaters do not concern themselves with celestial navigation at all, and figure that their chart plotter is all they need. Or their smartphone. So, they do not learn celestial. They do not even learn to keep a DR. No backup to electrically powered devices. No backup to satellites in orbit. No backup to software glitches in the system. Continued reliance on things outside the skipper's control altogether.


The way to be a proper navigator is to learn about longitude and latitude, and how to calculate both GC and Rhumb Line courses and distances, longhand and with calculator. Without that, you don't have a clue as to what your fancy chart plotter is really telling you or when things have gone terribly wrong. You need to learn to keep a DR. You need to learn how to take fullest advantage of GPS and other systems. And you need to learn to take celestial observations and reduce them to lines of position by both formulaic and tabular methods. The most fundamental principle of navigational prudence is having multiple methods of finding position now and in the near future. A backup GPS is not redundant. System goes down or is taken down, both are kaput. Lightning strike goes badly, anything with a transistor or an IC in it is likely to be toast. No, keeping your backup pocket GPS or phone in the microwave is not insurance. Half the yachts I have been on have no microwave anyway.



Is it necessary to be a proper and correct navigator to cross an ocean? Depends on how you define "necessary" I suppose. And whether you mean just cross, or cross safely. It is done all the time. It is just not done all the time with due prudence and diligence. It is not a good thing to ignore a resource that for very little expense and bother can add significantly to safety at sea.



There is nothing wrong with an antique sextant standing in readiness for use, for for actual day to day use with a GPS device for backup. As long as it is an actual instrument and not a decorative replica.


Just as a wise mariner ensures that he has practical tools and knowledge to use celestial navigation in the unlikely event of electronic failure, he also has multiple electronic devices with multiple means of powering or charging, for use when it is not possible to take celestial observations or if he drops BOTH of his sextants overboard. It is just as shortsighted to say to hell with electronic navigation as it is to say to hell with celestial. And regardless, a boat's skipper should be keeping a DR on a long passage. This means accurately estimating boat speed, calculating set and drift and leeway, all of that. Everyone wants to just pay their money, hop in a boat, turn the key and take off around the world with no education in the ways of the sea or the navigator or pilot. It is a miracle that there are not 10x as many fatal disasters as there are.
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Old 10-11-2019, 13:53   #70
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Re: Are antique sextants any good?

Quote:
Originally Posted by Adelie View Post
Actually you can get by without the chronometer.

actually you can get by without the boat - I've crossed way more oceans on commercial jets than I have in a yacht and i didnt need any nav equipment to do it...
perhaps the word 'chronometer' is misleading - a couple of digital watches @ $20 each, one for local, one for greenwich mean time - or, much more accurate, the clock in the GPS unit, which I have found myself staring at on the cabin table as I tried to motivate myself to do the tortuous calculations so I could compare the woefully inaccurate result against the bloody same GPS...
more to the point - as I was reminded - the OP wants something for practice - why not practice properly with a timepiece?
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