Natural Navigation - Sun quiz added

[roadrunner]

And while I would say that I don't use the sun much for orienteering navigation, I certainly felt disconcerted by it being in the north in Australia.

I was even more confused a while ago on holiday in the Southern Hemisphere to find that the sun was still South rather than North at midday

(If you're near enough to the equator, the Sun's in one direction at midday in summer and the opposite in winter!)

[tristgo]

I think you would have the sun on your right hand side(ish).

Mrs H wins the prize... for bravery at this point!

I'll see if there are any other takers out there before spoiling the fun, but will post the answers to 1 & 2 tonight. Such a tease.

[Mrs H]

sorry that was my answer to question 1 and so I might as well go for broke and say the answer to question 2 is to run straight back towards the sun
I don't mind being the fall guy.
.......and you see you have got the answer to question 3 - the one about why orienteers prefer to navigate using a map and a compass instead of lichen, moss and the sun/stars - because they don't want to wait around all day to finish a course!!!

Seriously Tristgo - I'm finding you definition of natural navigation quite restricted - given that we are almost totally reliant on observing the terrain - either through the course of making the map in the first place (no one has mentioned that yet) or relating the map to the natural features around us.

Do you think perhaps you should start considering a sequal to you book? How about "Natural Navigation - The Lay of the Land"

[Wayward-O]

1) On a December morning in the UK you run towards the sun for a half an hour at sunrise. How could you use the sun to help you run back to your starting point at sunset?

Keep sun on LHS (~90°)

2) How would you use the sun to cover the same ground, out and back, in June?

Out - Keep sun on LHS (~90°).
Back - Run towards sun.

[greywolf]

precise angles & bearings depend on yr latitude, so the exact answer is different from S of England to N of Scotland...

but crudely, in December if you run towards the sun at sunrise you are heading SE, but in an arc which curves to the right (more south than east) as the sun moves across the sky* in front of you (7.5 degrees every half hour). to retrace your steps, as the sun set in the south west you would need to start with the sun on your left hand side - this time you curve to the left a bit (towards the sun) - so if you started with the sun at 90 degrees left, after 30 mins it would be 75 degrees left

to cover the same ground in June, when the sun rises in the NE, you'd need to start with the sun away on yr left, and keeping it at a constant angle as you curve to the right. returning would involve starting to run more or less towards the sun (but again depends on yr latitude), but then as the sun moves right across the sky, you'd have to curve left.

*yes i am aware that it is the earth that rotates around the sun [/size]

[graeme]

December : use the light from the sun to pick out your footsteps in the snow. Follow.
June: As GW says, bearings depend on where you are. So best is to remember where you went in December.

What colour was the bear?

[tristgo]

Congratulations Wayward-O and Greywolf, both correct. Mrs H still gets the prize for bravery though.

Greywolf you're correct in stating that it varies by latitude. But are you ready for real spotter time?

The sun's bearing does not change by 15 degrees per hour (unless you are at one of the poles). Even though it is moving by 15 degrees per hour, due to the Earth's rotation, it is not normally moving parallel to the horizon and so its bearing will change by less than that at the start and end of the day for lower latitudes.

(The angle that the sun rises is very close to a figure called your colatitude, that is 90 degrees minus your latitude.)

To give you a really extreme example of this: the sun's bearing changes by nothing for several hours after rising at the equator on one of the equinoxes, but then flips and changes bearing instantly by a full 180 degrees at midday, from due east to due west.

I really must get out more...

[Spookster]

1) On a December morning in the UK you run towards the sun for a half an hour at sunrise. How could you use the sun to help you run back to your starting point at sunset?

I'd use it to try to keep warm in the 6 hours or so I'd been unnecessarily hanging around...

[rebbid]

yes trisco. Go orienteering.

[tristgo]

1) On a December morning in the UK you run towards the sun for a half an hour at sunrise. How could you use the sun to help you run back to your starting point at sunset?

I'd use it to try to keep warm in the 6 hours or so I'd been unnecessarily hanging around...

But Spookster, you would have finished long ago by using the stars, surely?

Random fact: the stars rise and set in the exact same place every single night when viewed from the same place, unlike the sun and moon which roam up and down the horizon.

[rebbid]

I'm sure if you can finish the black course at Tarn Hows without an unnatural map and compass someone may even buy your book.

[Roger]

Random fact: the stars rise and set in the exact same place every single night when viewed from the same place

...if you ignore the precession and nutation of the earth's axis of rotation.

[Scott]

Once precession comes into play you've definitely been out for too long.

[Mrs H]

Hey Tristgo - I see from your website that

At the moment, I’m trying to get the word out to the orienteering community about the joys of natural navigation

[Adventure Racer]

Most TV satellite dishes in the UK tend to point closer SSE (152 degrees, at the Astra 2 satellite).

To be pedantic, most should point at about 145 degrees if they're accurately lined up (closer to SE than SSE). The calculation to point at 28 degrees East is a little more complicated than simple subtraction - and of course varies depending on the latitude as well as the longitude (though it doesn't vary much over Britain, since Britain approximates a line pointing straight at Astra 2).

Of course just to be contradictory mine points at ~154 degrees (or should do, I doubt the alignment is that accurate)