Why use Celestial Navigation?

[arctic hobo]

Was treated to "Finding Your Way Without Map or Compass", by Harold Gatty for my birthday... what can I say but A++!
A superb book, all about natural skills with natural features, told by a very knowledgeable man indeed. I recommend this to all of you You can find it on Amazon.

 

[jamesraykenney]

Like pretty much everyone else here I think it's an essential skill, although less easy than you'd think. Finding north is fine, but if you have to go say 150 degrees it's hard to orientate yourself, especially if there are no landmarks. In the arctic we used (use?) it most of the time as with 24 hour darkness there's no reason why not, and it saves your hands for your ski sticks and rifle. Plus the further north you go the less accurate your compass is. A compass is great for backup, but in low temperatures you may find the compass fluid freezes (mine did and broke :roll. A cheap non-fluid compass is an important backup, as in the mountains you can be in cloud for weeks.
In more temperate climes a compass is of course the easiest way, and by no means un-bushcrafty: the Vikings used a "lodestone" (magnetic rock) compass for navigation.
Doc having been taught Sextants before (in fact I am qualified to teach it), I cannot see how you could use it on land. You need a perfect horizon fix - on the sea you're at sea level looking at a sea level horizon. Throw land in and you'll be all over the place! :?:

You were never taught how to use an artificial horizon???
They are very simple and at one time were considered standard equipment!

 

[jim_w]

The use of lodestone by the Vikings is uncertain but possible. Most of their deep sea navigation appears to have been achieved using a bearing dial or "sun compass"

I have tried one of these devices myself and they have the advantage of needing no modern equipment to make or set up, all can be done by observation.

I can't really work out how one of these things works from looking at that link... Any clues?

Oh, and hello all.

 

[Wayland]

Ok, this is how I would set one up from scratch with no known directions.

First you need a fixed height gnomen on a disk. Mark off a point on the edge (any point will do for now) place it on a level surface in the sun with the mark pointing at a fixed object (this is to make sure all your readings are taken without moving the dial).

Now as the sun rises the sun will cast a long shadow roughly westwards. When the lenght of the shadow is short enough that it's pointjust touches the edge of the dial make a mark at that point. As the day proceeds, the shadow will get shorter and pass the gnomen before starting to get longer again. eventually it will drop of the edge on the eastern side of the dial.

All through this process you are going to mark the point of the shadow's position, say every 30 minutes or so. The western and eastern points are very important, make sure you get them both. You should now be able to joint the dots to make a continuous, curved line from east to west.

The north south line will now be at right angles to an imaginary straight line between the east and west edge marks. These points can now be marked on the dial. All other points can now be marked, geometricly from north / south.

That is how it is made, so how does it work.

Firstly it will only work at aproximately the same latitude and time of year that it was made. So short term use really.

Take the dial, hold it level and rotate it until the length of the shadow is just the right length to touch the curved line. It will of course touch in one of two places so you need to know if it is morning or afternoon. in the morning use the westerly side of the dial and pm. use the easterly side.

When the shadow tip touches the line on the correct side of the dial, all points of the compass should now line up perfectly.

I hope that makes sense to you. I can see it perfectly but I have the andvantage of knowing how it works already. If it still doesn't make sense I'll try and explain it a different way if I can.

 

[jim_w]

Yeah, that makes perfect sense

I'm pretty sure I understand the principles there - in fact, I remember as a child thinking that a stick stuck in the ground could be used as a compass in much the same way!

Just one question - what's a gnomen? For once, google appears not to know!

Thanks a lot for that - next time I'm in the sun I'll try it!

 

[Wayland]

The gnomen is the bit that sticks up on a sundial.

On these things it is just a conical pin in the centre of the dial.

BTW. welcome to the forum. You'll find they're a nice bunch of people here, I've found out loads of things from them all.

I do quite a lot of work based around the Vikings with the guys at Murton Park just outside York.

 

[Ogri the trog]

Light pollution is a major problem for a lot of people in the Uk, a few years ago a campaign was started to try and educate local authorities on the benefit of none wasteful lighting systems ie ones that throw light where people need/want it and not all over the place.

I bet not many people in the uk have seen the Milky Way or looked through a telescope and appreciated just how many stars are up there and what beauty they are missing.

A friend of mine recently pointed out four of the planets in our solar system that you could see with the naked eye, had we had a pair of bino's or a scope, it would have been five, Neptune (IIRC) was just too far away

At home on a clear night, you can nearly read by starlight, we can regularly see satelites going overhead and the house can cast a shadow in the moonlight - something to amaze visitors.

Ogri the trog

 

[arctic hobo]

You were never taught how to use an artificial horizon???
They are very simple and at one time were considered standard equipment!

You don't need one at sea...?

 

[Stuart]

I hope that makes sense to you. I can see it perfectly but I have the andvantage of knowing how it works already. If it still doesn't make sense I'll try and explain it a different way if I can.

I think I have that worked out, but for those of us that are still confused (which might include me) would it be possible for you to put together a tutorial with pictures or diagrams?

 

[Wayland]

I can recommend and excelent book which covers the subject in detail.

Viking Navigation by Søren Thirslund. (Sun-compass guided Norsmen first to America) 2001

ISBN 87-984079-6-1

I got my copy in Norway but I believe you can get it direct from the publishers:

The Viking Compass, S. Thirslund, 342, Teglgårdsveg, DK-3050 HUMLEBÆK, Denmark

I'm not sure I could put together a tutorial but I'd be glad to demonstrate it if I ever get to one of the meet ups. (They all seem to happen when I'm unavailable )

 

[Stuart]

thanks Wayland

can you not make the moot at the end of july in south wales??? you'll really be missing out on a great weekend if you cant

 

[Wayland]

I'll be on my way to Lofoten then I'm afraid.

Well actually I'm not afraid at all, in fact I'm ecstatic if the truth be known but it does mean I'll miss the moot which is a shame.

Anything post September sounds good to me.

 

[arctic hobo]

thanks Wayland

can you not make the moot at the end of july in south wales??? you'll really be missing out on a great weekend if you cant

If we ever coincide meetups I can explain.. I've been reading up on my ancient navigation techniques