With the advance of technology, locating yourself wherever you are has become a task that requires only a few seconds.
We simply have to open our mobile devices or any type of GPS and we will have, with total precision, our exact position.
But this has not always been the case.
Ancient sailors had to manage to find their way, and this is something they did thanks to our most faithful friend: the stars.
In this post we will discover exactly how they did it.
We will see what astronomical navigation is, how to navigate with stars, and many other curiosities that will allow you to appreciate this great art.
Navigation and astronomy, always linked
Navigation and astronomy have always been closely linked.
The navigator has needed to look at the celestial vault to answer the question he has always asked himself: Where am I?
Today, especially for citizens living near large cities, light pollution prevents them from enjoying the night skies and the landscape of stars and constellations that our ancestors enjoyed.
The navigator, on the other hand, is fortunate to enjoy dark skies, free of light pollution, as he is only a few miles from the coast.
If we are navigating in any modern vessel and we ask our position, any of us will be able to answer in a few seconds.
It will only be necessary to press the “on” button of the GPS or look at our mobile device.
In a voyage in which we lose sight of the coast, in a few miles we will no longer have coverage to talk or send messages, but, instead, we will keep our exact position throughout the voyage: latitude and longitude, and the accuracy is amazing.Astronomical navigation is an art, which unfortunately is being lost due to electronic navigation.
As Mr. Luis Mederos, a reference in this art and author of the book “Astronomical Navigation”, says, electronic charts, plotters, the autopilot connected to the GPS that is capable of piloting the ship between any two points without human intervention, etc., have made a sextant look like an antediluvian instrument and, what is worse, it is much more expensive than a GPS!
To make matters worse, practicing astronomical navigation with guarantees requires studying…
Why don’t we look at the sky anymore?
If we no longer need to look at the sky to determine our position…why should we?
In order to convince future students or sailing enthusiasts, we can continue to insist that the boat could run out of electronics and lose all GPS signal.
At that point astronomical navigation, if we have no land in sight would be critical.
However, this reminds me of a day when I was talking about the convenience of knowing how to use the sextant, a student told me how many GPGs he wanted me to take on board, because even in our cell phones we already have our exact position.
Frankly, the argument seems quite convincing.
So, perhaps now it is not a matter of looking at the sky to calculate our position, but to continue to do so for pure pleasure, to enjoy a new landscape that opens up beyond the sea and our sails.
I think there is a moment of metamorphosis in which we go from considering that the sky is full of dots of light, to consider it a new landscape.
This happens when someone, with certain teaching skills, manages to explain to us what those dots we see are, how the navigator has used them in the past to orient himself, or even adorns them with curiosities or mythology about some of those stars or constellations.
I recently heard the great master Joaquín Sabina say that when he was at an airport on tour, and suffered a delay, he always listened as most of his team lamented bitterly.
On the other hand, he commented that he took advantage of that moment to take out the book he was reading, look for the point of the book, and continue to enjoy reading it while waiting.
Saving the obvious differences, I like to compare this fact to what happens to a navigator when he has to do a night watch.
You probably feel more like staying asleep, not getting cold, etc.
On the other hand, if we know this new “starscape”, which is always different throughout the year, we can enjoy discovering those stars, constellations, meteors, etc. that travel the celestial vault during our watch.
How do you navigate with stars?
To observe the sky, it is essential to learn to orient oneself and recognize patterns, figures and paths that will help us to remember the position of the most important stars and constellations. Below we analyze the most important points for navigating with stars.
The most important tools of astronomical navigation
Seafarers have always lived with their eyes on the sky. Already the first inventions to determine latitude used the position of the stars.
One example is the astrolabe, whose meaning derives from the Greek “star finder”.
The sailors adapted this instrument to be able to measure the height of a given star, and also to determine quite accurately the position of the Moon, the Sun, and the planets in relation to the stars.
Its use was given one of those names I love related to ancient navigation: “pesar el sol” (weigh the sun).
Other instruments such as the Ballestilla, or the Kamal, which we will talk about in future articles, had already been used in the Middle Ages and gave way to the octant, and later to the sextant and chronometer.
Navigation in the Middle Ages was limited to cabotage; that is, sailing from cape to cape. Rarely did seafarers venture into unfamiliar seas or do so at night.
The ballestilla is a wooden rod on which a smaller crossed rod slides.
The rod was made to coincide with the horizon and the upper one with the sun or the star.
The reading was made on a graduation of degrees and minutes printed on the main rod as a limbo as in the sextant.
This also reminds me that many of us thought that all those characters that appeared in pirate movies with an eye patch were probably due to duels and epic battles with swords.
The reality is that many of them lost their sight by looking directly at the sun to take up positions with the crossbow, and later the sextant.
Nowadays sextants incorporate powerful filters that allow us to “lower the sun” safely for our eyes.
Knowledge of the winds was essential
Whoever knew the winds dominated trade.
Some ships even drew the compass rose on their bows, and nautical charts made it possible, with many errors, of course (Mercator did not arrive until the 16th century), to draw known loxodromic lines.
Navigators followed them faithfully, even though they knew that they would often travel much further, but the important thing was to reach their destination, to “touch land”.
Hence the saying of the time: “Parallel run, land find”.
If anyone would like to see the primordial precursor of the compass rose, just go to Athens and there in the Agora you will find the Tower of the Winds.
The compass, an indispensable instrument at sea
It is assumed that the compass was introduced by the Chinese culture in the 11th century.
This instrument removed the traditional closure of the sea during the winter months, which had persisted in the Mediterranean for millennia.
The compass was initially considered as an instrument to which even almost magical powers were attributed.
It marked the north but it was not well known why.
For that reason the captains of the ships kept it with great zeal in their logs, and even the law allowed that anyone who dared to touch a compass without the captain’s permission, could have his hand nailed to the mainmast with a dagger.
A curious rule…
When the coast was no longer in sight, they sailed “a la estima”, minutely noting their course, downwind and drift.
The method of “heights and distances” involved knowing the latitude of the starting point and noting new positions during the voyage.
The position at which the ship was supposed to be at any given moment was called “fantasy point” (another wonderful term…), which was refreshed or corrected with measurements made with astrolabe, crossbow or later sextant to form the “squadron point”.
Navigating through the North Star
In the northern hemisphere we have been fortunate to have the most useful of all stars, and not precisely because it is particularly bright, since its magnitude, which is how we measure the apparent luminosity of the stars, is only +1.97, but because its position practically coincides with true north (it is currently less than one degree, at 43′ 11″). is less than one degree away, 43′ 11″)..
Esa estrella es Polaris.
Además, y esto es algo que no puede pasar desapercibido, su altura respecto al horizonte visible, ha permitido calcular la latitud del observador con bastante precisión.
Por ese motivo, si pudiésemos medir la Polar desde el Polo Norte la veríamos en su zenit (90º), mientras que si la medimos en el Ecuador la veríamos sobre el mismo horizonte (0º).
A term commonly used by all is that of “septentrional”, which derives from the seven oxen of the chariot of the greater bear, that is, the seven stars, and means: the most northerly.
We cannot forget that due to the Precession movement, Polaris has not always marked the north (previously it was Pherkad also of the constellation Ursa Minor), and in about 12,500 years from now that honor will correspond to the star Vega of the constellation of the Lyre.
For the time being we continue to enjoy its position, and affirm that latitude was never a problem for sailors, but longitude took almost three centuries to be solved.
Also the latitude by Meridian of the Sun was already used before 1484 by navigators who crossed the equator and lost the Polar.
The great discoverers, both Spanish and Portuguese, carried out their discoveries, at the end of the 15th century and first half of the 16th century, with no other help than the Polar and the Meridian.
When the sun passes through the meridian of the place, the position triangle disappears to become a meridian arc, and the latitude can be determined by a simple algebraic sum (90º – True Height +/- Declination).
Ursa Major, circumpolar constellation with history
I cannot conclude without making a brief mythological note related to the Big Dipper: “Hera’s punishment”.
The constellation Ursa Major is surely the most popular of all in the northern hemisphere as we have seen.
In some places it is known as the frying pan, the saucepan, the Plow, or Odin’s hammer.
The constellation is accompanied by another set of stars with a very similar shape but smaller in size: the Little Dipper.
The story of this pair of Bears has as its protagonist Zeus, king of the gods according to Greek mythology.
Zeus was married to Hera, the goddess of marriage, but he had many affairs.
From his relationship with the nymph Callisto, Arcade was born.
When Hera found out what happened, she transformed Callisto into Ursa (Ursa Major).
As fate would have it, Arcade crossed paths with his mother (Callisto), already turned into a bear, and as he did not recognize her, he aimed at her with a bow and arrow.
Let’s remember that Callisto was from the court of the goddess of hunting, Artemis, and perhaps that’s where Arcade got his love for hunting… When he was about to shoot, Zeus intervened and also turned Arcade (Ursa Minor) into a bear.
So that they would not both be scratched by his claws, he threw them into the sky by their tails.
When Hera heard what had happened, she was furious.
She went to see her brother Poseidon, the God of the seas, and asked him that neither the Big Dipper nor the Little Dipper could bathe in celestial waters; that is why neither of these two constellations ever disappear below the horizon line in mid-latitudes.
Mythology sometimes also served to explain astronomical phenomena as in this case the circumpolar constellations.
Start your astronomical navigation adventure at Sea Starlight
The world of astronomical navigation is undoubtedly fascinating.
It allows us to go back in time, to be more present in our navigation route, and to rediscover more than interesting stories of mythology.
And thanks to the Sea Starlight project, this is available to everyone.
We have astronavigation experiences all over the Spanish coast with certified Starlight monitors, who will make you live in first person the navigation with stars.
Do you want more information?
