Winter, keep fit for celestial navigation

gonio_uso If you have tried celestial navigation, and you have become an enthusiast, you may have discovered that in order to have a certain confidence with such discipline you have to keep trained as for any other discipline.
Nothing better then using your own Star Finder and build a simple tool that will give you endless exercises during the winter season waiting to put into practice during your summer cruises, all that you have learned in the cold winter days. We have already discussed in another article the Star Finder a very useful tool used in celestial navigation for two main purposes: the first finding the position of the stars in the sky at twilight in order to prepare the sextant to easily observe the celestial bodies above the horizon , the second, once spotted a celestial body in a stretch of sky covered by clouds, figure out which star it is and use it to get your fix. Moreover, if you have already practiced a little ‘celestial navigation you will realize that it is not always easy to find the ideal conditions for their observation and it is more common to find, even in the ocean, an overcast sky with some glimpse here and there than a clear sky. It is in this type of observations, on these occasions, that the Star Finder will show its best for its simplicity and speed of use.
To help in this type of exercise from your garden or balcony of your home, you will need to equip yourself with a simple tool that I will show you how to build it yourself in this article. In a future article, if you had the patience to build one, will accompany you in its practical use.
This tool will have the task of replacing the sextant with artificial horizon, as in an urban landscape will undoubtedly miss a sea horizon from which to measure the height of the stars and a simple sextant, there, would be unusable. Some might argue that using a simple pan filled with oil, you can get a simple artificial horizon, but this is going to complicate your life and make you learn the technique to find the reflection of the stars in this sort of mirror, which, at sea will be practically useless. In addition, to recognize a star using the Star Finder, you do not need certainly the precision of a sextant.
We go now to the list of required materials that you can also see in the pictures attached:
A long piece about 30 cm. of Poster rail
A protractor from cheap plastic sturdy and quite large
A long piece about 35 cm. of thread (the one for silk embroidery is the most suitable for softness and strength)
A small fishing weight of about 25 or 30 grams, but it’s OK to any other weight as a steel nut.
A toothpick (optional)
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I chose a poster rail, but a little piece of plastic pipe or a straw would do the same, simply because the poster rail proved to be the best when attaching it to the protractor with some glue and getting a tougher instrument able to endure.
Take care to assemble the protractor and poster rail so that the origin of the thread line matches precisely to the reference center of the arc scale of the protractor. For the most demanding, split in half a toothpick and insert it in the poster rail at the extremes, to protrude inside the line of view and improve the accuracy of the sights.
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Finally, most of you have already understood how to use it all and get the height of a star, you can use it at any time because it is not necessary to have a visible horizon. Just a minimum of exercise to learn how to block with a light touch the thread in the position corresponding to the height angle and be able to read it comfortably.
Fair winds and see you at the next episode!

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