Celestial Navigation

[happyfilmluvguy]

I was discussing with a friend about compasses, North, South, East, and West. One technique in navigation, that I believe is used much more than believed, is by the stars. I've never done it before, and my idea of navigation is not exactly ethical, but I was wondering, how do you navigate by the stars?

 

[Nigel Fisher]

Well, the North Star is always in the north.

You memorize the locations of other constellations, and track from there. For example, if [X] is normally east of the North Star, in [X] position, and it moved you can extrapolate where you are.

 

[Staredge]

Well, if you're talking about nautical navigation: celestial navigation uses the position of the sun and stars to basically triangulate where you are. By using the altitude of a given star and what time you make your observation, you can then determine where you are on a line. Turn a different direction and make the same observation on a different star, and that gives you another line. Where those two lines intersect is your position. (using a third star gives you a better reading) It involves sextants, calculators, and a big book of reduction tables. As much as I'd love to learn, I haven't yet.

Try http://www.celestialnavigation.net/ for more info and a MUCH better explanation.

Will

 

[Feraud]

I was discussing with a friend about compasses, North, South, East, and West. One technique in navigation, that I believe is used much more than believed, is by the stars. I've never done it before, and my idea of navigation is not exactly ethical, but I was wondering, how do you navigate by the stars?

I would think most sailors today are not navigating by the stars when GPS devices are available.
What do you mean by your idea of navigation as not exactly ethical?

 

[nobodyspecial]

I think you hit the nail on the head. You take some readings with a sextant and run a series of math equations to determine your location. Shackelton's crew did a bang up job with a sextant on the voyage to South Georgia Island.

 

[Twitch]

The ancients navigated by the constellations before compasses existed along with the North star because after observing their movement for decades or even 100s of years it is possible to move across the water at night keeping the ever-moving constellations in relative bearings. By doing that you hold a true course.

Let's say that Orion, viewed as it traverses the night sky, must always stayto starboard. If you find yourself facing it you must correct course.

 

[rumblefish]

Navigating by using stars can be as simple as knowing what is where in the sky at what time and what date. I fish at the continental shelf from New Jersey to Nantucket on two and three day trips. During clear nights and knowing the time, it's easy just to look up to get your bearings. If any electronics ever fail (Loran, GPS, or a light on your compass) picking something in the sky and aligning it to a point on your boat (a rail, out rigger, etc), and glancing to it to keep it there (make corrections as time passes), is a simply way of navigating by stars. But that's getting from point A to Point B. Finding a "spot" in the water where there are no land references takes the tools mentioned above. Dead reckoning I leave to the old timers.
I've taken our boat from 110 miles offshore to port without positioning or nav electronics, but without radar... it's very dicey, unless it's clear and every available pair of eyes are "looking out".

 

[Lucyinthesky]

I was discussing with a friend about compasses, North, South, East, and West. One technique in navigation, that I believe is used much more than believed, is by the stars. I've never done it before, and my idea of navigation is not exactly ethical, but I was wondering, how do you navigate by the stars?

I remember visiting the star of india in San Diego and seeing some old compasses on that ship and thinking to myself ....how did those old sailors navigate??

 

[Harp]

I've never done it before, and my idea of navigation is not exactly ethical, but I was wondering, how do you navigate by the stars?

Orion's belt or its cardinal star Betelgeuse are easily recognizable and follow to the North Star.

 

[Peacoat]

For precise celestial navigation one needs a marine chronometer, a sextant, an almanac giving schedules of the coordinates of celestial bodies, a set of sight reduction tables to help perform the height and azimuth and a chart of the region. Not much if any math is needed as that has already been worked out for us. The methods noted above work, but they are more dead reckoning than precise navigation.

Plastic sextants for practice can be bought rather inexpensively, and courses are available to teach the method. An area will be needed in which one can see the horizon and a few select celestial bodies. A little practice in one's backyard, and the seas beckon. Careful to sail only when the horizon and the stars are visible, though.

The navigators on the bombers in WWII could, and often did, use celestial navigation. When I was in flight school it was mentioned, but that was about it.

Bon Voyage

 

[EngProf]

Suggested reading:
"Longitude" by Dava Sobel
It discusses the early navigation problems (determining longitude) and the development of the marine chronometer by John Harrison as a means of determining longitude.
A good and informative book...

 

[Haversack]

Astronomy for Field Artillery is still taught. Its all about getting a true azimuth. Field Manual 6-2 explains it step-by-step.

 

[Tiki Tom]

Always a topic of great interest to me. When he was exploring the Pacific in the 1770s, Captain Cook was astounded that the language he became familiar with in Tahiti was clearly related to the languages spoken in such far flung places as New Zealand (Aotearoa), Easter Island (Rapa Nui), and Hawai’i. The ancient Polynesians sailed in double-hulled canoes and were masters at navigating by the stars and wind and wave patterns. More than 1,000 years ago they were navigating across the vast Pacific and making precise landfalls on tiny islands. It is an amazing topic and mysteries remain. The modern voyaging canoe, Hokulea, is trying to revive the old knowledge and to educate a new generation about Polynesian culture and navigating by the stars.

http://www.hokulea.com/

Very interesting topic!

 

[Peacoat]

Always a topic of great interest to me. When he was exploring the Pacific in the 1770s, Captain Cook was astounded that the language he became familiar with in Tahiti was clearly related to the languages spoken in such far flung places as New Zealand (Aotearoa), Easter Island (Rapa Nui), and Hawai’i. The ancient Polynesians sailed in double-hulled canoes and were masters at navigating by the stars and wind and wave patterns. More than 1,000 years ago they were navigating across the vast Pacific and making precise landfalls on tiny islands. It is an amazing topic and mysteries remain. The modern voyaging canoe, Hokulea, is trying to revive the old knowledge and to educate a new generation about Polynesian culture and navigating by the stars.

http://www.hokulea.com/

Very interesting topic!

And however they were doing it, they weren't using a sextant. because it wasn't invented until about 1730. Or perhaps they used their own version of the sextant?

 

[Harp]

Astronomy for Field Artillery is still taught. Its all about getting a true azimuth. Field Manual 6-2 explains it step-by-step.

A battery of 109s laid against the spectacular Oklahoma sunset, gates of Heaven closure with all guns fired salute.
Then the stars appear as if by magic over Ft Sill's gunnery range. Not even the Pali on Oahu approaches this display.

 

[Tiki Tom]

Fun read:
https://www.popsci.com/sea-people-excerpt