How the #$%^ does someone navigate using the stars?

Question

Ive heard of people doing it in TV, movies, books, games, whatever.... just how can you navigate a boat in nightime using 23235203502935235 different dots???

Answer 1

To follow on from the tugcapts good answer - True celestial navigation is a full time job - You take two very accurate position fixes a day, one in the morning just before sunrise, and one soon after sunset.
This is done then as it needs to be dark enough to see the stars/planets yet light enough to see the horizon as a crisp line (sometimes with a (nearly)full moon you can take sights throughout the night as it illuminates the horizon). At those times you want to take as many sights as you accuratley can - the more LOP's you have the more accurate your final position is going to be.
One thing to remember when you are taking multiple sights is to remember your ship is probably moving, so you need to adjust your calculations to all correspond to one time, ie. take a sight every 3 mins - 17:51 17:54,17:57, 18:00, 18:03, 18:06, 18:09 and then calculate your position for 18:00.
This is important as say for example you are travelling 20 knots - your ship would have traveled about 7 miles from the first sight to the last so you need to correct for that.
So, you have the 2 very accurate ones at twilight, then an amplitude at sunrise to ensure your compass is working correctly (you can take a bearing of a celestial object and then mathematically calculate what the bearing should be for your time and position and compare that to your compass reading) a 'morning sun' to check if you are on track, 'Meridian passage' at midday - that is when the sun is at its highest point in the sky, and from that we can work out or latitude, 'afternoon sun' to check our track and then evening stars as an accurate fix, then an Azimuth to check your compass during the night (tho really you should check your compass every 4 hours as a minimum) All in all its ALOT of maths to do in one day :s
As an aside you can also easily find your latitude by using Polaris, or the pole star/north star as some call it. As it happens the angle from the horizon to Polaris is very very close to your latitude north of the equator...
Oh, and by the way its a very common misconception that Polaris (pole/north star) is the brightest star in the sky - its in fact nowhere close, something like 48th brightest, where the brightest is infact a star called Sirius (anyone seen Harry Potter?, well, the other classical name for that star is 'The Great Dog')
Hope ive not confused you all even more? :)

Answer 2

The simplest form of navigation is to find the north star by the
pointer stars in the Big Dipper. Now you know which way true north is. In navigation, they use what is called a sextant. It measures the angle of how high a given star is above the horizon. With charts and other reference information, knowing the angle gives you your lattitude. If you know what time it is, you can also get your longitude from this information. So, they don't use a gazillion stars, they just use the right ones.

Answer 3

First you need to know your constellations. Then you pick ones that are visible. Then, using a sextant, you "shoot the stars" in the morning, and in the evening. That will give you your days run. also you can shoot a bearing on the sun during the day, and advance your morning star fix, to fix a noon position. Each bearing on the stars is a line of position. you need more than one line to plot a fix. The actual mechanics of doing it involves alot of theory, practice with the sextant, aledade, and azimuth circle. Basically once you have your altitudes, you enter into the sight reduction tables, and nautical alminac, then perform a triple interpolatoion calculation to get the bearing. That with the time gives you a LOP, and more than one gives you a fix. This is a rough explanation, but that's it.

Answer 4

Of all of the stars the are in the sky, you only use 52 of them. to find out what 52 to use, you need to use a Nautical Almanac and look up the month of year you are in, it will tell you what stars that are available for that time of year. then you will also need a stop watch, a sextant, and a understanding of Celestrial Formulas.
You can also use 4 Planets.( Moon, Venus, Jupiter, and Mars) for the Position Fixes.

Answer 5

You do need some equipment in order to do so, such as a compass, a clock, and a sextant. A sextant will enable you to sight on the North Star (Polaris) and determine your lattitude. Longitude is tricky because you need a time measurement to calculate it. Take a look at this website.

Answer 6

If the two dippers won't be in a position to be got here across then you relatively are in all probability in the southern hemisphere. if so fing the Southern circulate and that supplies you an tough concept the place south it. for sure north would be in the choice direction.

Answer 7

I guess the North Star is the main source of direction for most sailors. If you have that recognized in the sky, since it is the largest star, that keeps your compass bearings OK

Answer 8

Its called celestial navigation that's why they kept track of the date and carved it into trees when ship wrecked all they had was the stars now we have GPS

Answer 9

The easiest way I can tell you is to look for the big dipper. The big dipper has the North star in it. Since the north start obviously is in the Northern part of the sky, base it off of that.

Answer 10

You look for a particular dot...in most cases, Polaris, the north star.

It's all based on time of year and constellations.