Celestial Navigation

[openseas]

Hi all,
I just finished day one of a two-day course about celestial navigation, including how to use the sextant and get a fix.
The people who were taking the course, all have some knowledge about the sextant including some who already use it.
For me, seeing the instrument for the first time, the course had a steep learning curve.
Do you suggest any books or DVD's that would simplify the instrument and take someone like me from scratch.

Thanks a million,

[sabray]

Reply to wrong thread

[Teknav]

With the GPS being as cheap as it is and as easy to use, why on earth learn to use a sextant? Does it make any sense to use a slide rule/an abacus when pocket calculators are easier to use and cost next to nothing? It's time to move forward, folks!

Mauritz
I solve complex engineering problems using very fast computers.

[C4 King Cobra]

Self taught Navigation by Robert Y. Kittredge

[sabray]

Now I will reply. The reason is because its knowledge. It gives a nice sense of understanding. It can be enjoyable, frustrating and something to entertain oneself with.
Of course you could just google where am I?
Or try swinging the sextant.
I just found out I'm on the US East coast, Middle age, my hair line is receding, the fence in my backyard is not complete. 2.5 kids, do not have a established Facebook page, no twitter account. Someone near me with the same name is hosting a ginsu party next week. I'm going to google ginsu.

[goboatingnow]

Originally Posted by Teknav

With the GPS being as cheap as it is and as easy to use, why on earth learn to use a sextant? Does it make any sense to use a slide rule/an abacus when pocket calculators are easier to use and cost next to nothing? It's time to move forward, folks!

Mauritz
I solve complex engineering problems using very fast computers.

Philistine

[openseas]

I want to learn about the sextant as a back up source, when your GPS or other electronic don't work, or when a lightening fries all your electronic, so that I can get back to shore.

[nigel1]

Download Bowditch Practical Navigator from here
Maritime Safety Information
Big chunk on sextant use and celestial nav

More info here
A Short Guide to Celestial Navigation

and here
Practice @ Celestial Navigation


Try to get to understand the principles of celestial nav, helps to get an understanding of what you are doing.
Dont sweat the maths, thats the easy bit

Try and borrow a sextant and just practice using the thing

[nigel1]

One more
Celestial Navigation for Dummies - page 1

If you read through the pages (slowly) it will give you some idea of the principles of CN

[sailr69]

Originally Posted by openseas

Hi all,
I just finished day one of a two-day course about celestial navigation, including how to use the sextant and get a fix.
The people who were taking the course, all have some knowledge about the sextant including some who already use it.
For me, seeing the instrument for the first time, the course had a steep learning curve.
Do you suggest any books or DVD's that would simplify the instrument and take someone like me from scratch.

Thanks a million,

just learning how to use a sextant is not hard, are you referring to using a sextant to get fixes? that is not easy. taking sights in the 18th century was a military secret. the us military published the method for all to use and study. there are books to use but the best way to learn it is from classes and on the job training. there are two ways to reduce sights, air navigation tables or Marc St. Hilaire method. either one takes training.

[sailr69]

Originally Posted by nigel1

Download Bowditch Practical Navigator from here
Maritime Safety Information
Big chunk on sextant use and celestial nav

More info here
A Short Guide to Celestial Navigation

and here
Practice @ Celestial Navigation


Try to get to understand the principles of celestial nav, helps to get an understanding of what you are doing.
Dont sweat the maths, thats the easy bit

Try and borrow a sextant and just practice using the thing

the math is spherical trig, can be done with Norries tables of haversines and with the use of logrithims. I did not find it very easy. some might. you may program some scientific calculators to solve some of the problems. I think nowadays you can find some already programed.I used to be very good at it, one sighting took me 15 minutes to get a reduction.using the Marc St. Hilaire method. to use celestrial navigation only, to find your way around the seas it would take morning to dusk to make a navigational day. sun azimuth in morning, noon sight, afternoon sun azimuth and then evening stars with several stars. and with dr plotting every hour. busy day! air navigation tables speeds it up but the plotting is harder. you also need the appropriate HO book

[goboatingnow]

Originally Posted by sailr69

just learning how to use a sextant is not hard, are you referring to using a sextant to get fixes? that is not easy. taking sights in the 18th century was a military secret. the us military published the method for all to use and study. there are books to use but the best way to learn it is from classes and on the job training. there are two ways to reduce sights, air navigation tables or Marc St. Hilaire method. either one takes training.

The methods were published ( in so much as there were there) long before the US military even existed

Dave

[goboatingnow]

Originally Posted by sailr69

the math is spherical trig, can be done with Norries tables of haversines and with the use of logrithims. I did not find it very easy. some might. you may program some scientific calculators to solve some of the problems. I think nowadays you can find some already programed.I used to be very good at it, one sighting took me 15 minutes to get a reduction.using the Marc St. Hilaire method. to use celestrial navigation only, to find your way around the seas it would take morning to dusk to make a navigational day. sun azimuth in morning, noon sight, afternoon sun azimuth and then evening stars with several stars. and with dr plotting every hour. busy day! air navigation tables speeds it up but the plotting is harder. you also need the appropriate HO book

I would not recommend anything other then a method that can be worked through without ANY electronic assistance. Table based spherical trig solutions are very error prone and not really for thing for a newbie , use a paper worksheet approach and learn a completely paper based approach first. , intercept / st. Hilare is a simple to use method with no complex tables and purely add and subtract math.

Air tables are the best for small boat use

[Meandercp]

I used Celestial Navigation with H.O. 249 by John Milligan to learn in the late '70s.

When I Googled it to see if it was still in print, I ran across a free downloadable version at:

CELESTIAL NAVIGATION BY H. O. 249 - DOWNLOAD FREE

As long as I was looking, I found downloadable HO 249 tables at:

Ho 249 sight reduction tables - free eBooks download

It does seem a bit odd to use a computer search and downloads in the furtherance of luddites.

[sailr69]

Originally Posted by goboatingnow

I would not recommend anything other then a method that can be worked through without ANY electronic assistance. Table based spherical trig solutions are very error prone and not really for thing for a newbie , use a paper worksheet approach and learn a completely paper based approach first. , intercept / st. Hilare is a simple to use method with no complex tables and purely add and subtract math.

Air tables are the best for small boat use

what is a purely paper approach? that one is new to me. I print a paper form for reductions but still need to do the math to fill it in. btw, I don't do celestial anymore, not for 20-25 years. maybe some things have changed