Here’s an interesting solstice fact for you: the Earth is actually receiving more solar radiation at this time of year than at any other time. This is because the Earth does not orbit the sun in a circle, but in an ellipse. In the northern hemisphere winter the Earth is at its closest to the sun, a point called ‘perihelion’, but in summer it is at its furthest point, or ‘aphelion’.

The Guardian have published a little article on the timing of the winter solstice.

However, my favourite solstice image is on a different page. The same technique used in the photo on that page, from the same position, but on the summer solstice would probably not catch the sun at all, or perhaps just a glimpse of it in the top corners.

At this time of year the sun is always lower at any time of day than it would be in the summer. This means the number of times when it is out of sight is also much greater. In one sense, of course, the sun is out of sight when it is nighttime – I always like to think of the sun being due north at midnight, even though it is underground. But there are many times when it is not night, but the sun is still so low that it is hard to find.

At the start of end of the day the sun will often hide behind clouds, buildings, woodland etc. Even in the middle of the day it will still be a full 47 degrees lower in the sky than in late June. That is to say you could fit almost five outstretched fists between the two solstice suns at midday, one on top of the other.

The fact that the sun is lower and there are more clouds in winter make it a good idea to remain aware of a simple technique. It is the sort of thing that when you think about it, it seems ridiculously obvious, yet it is easy to not consider it at all.

Clouds can act as a mirror, much in the way the moon does, and reveal the approximate direction of the sun. In the image above, which I took a few days ago, the sun has long since abandoned the surrounding land. It would be all too easy to imagine that it was lost as a source of direction-finding altogether. However, if you look at the clouds they are pointing the general direction of the sun for us, it is to the right of the picture. Since this was taken in the afternoon, the sun will be in the southwestern part of the sky and so we must be looking in a southerly direction.

If you are lucky you can find clouds in more than one direction that are lit on one side, sometimes a collection of mirrors forms that allow you to pinpoint the sun fairly accurately, despite the fact you cannot see it. (This is a technique I often find myself using on aircraft, if I am keen to work out the direction the aircraft is heading, but only have a perspective that does not include the sun).

There is one other aspect to this technique that makes it a favourite in winter. We get more unsettled weather in the winter months and the accompanying tall clouds. Bad weather is often preceded by towering cumuli and arrives with cumulonimbi, these giants can block out the sun, but they do occasionally hint at its whereabouts too.

The example above is obviously at the simplest end of the spectrum, sometimes it is much trickier – and can be more fun, if the pieces of the jigsaw fit! Which reminds me, it is nearly time for me click into Christmas mode.

I shall doubtless shortly be encouraged to help with some ludicrous jigsaw puzzle of the cardboard variety. But I shall seek my revenge by dragging everyone’s turkey-swollen bodies outside to do a cloud and sun jigsaw puzzle afterwards.

Happy Puzzling Times!

When I was told that we were going down a slate mine in Snowdonia and that it would be great if there were some natural navigation clues to help us find our way in the mine, I was initially a bit concerned. Natural navigation methods can be used in a very wide variety of locations, including underwater, but I have not spent any serious time caving or in mines and so feared it might be a non-starter. It quickly became clear that I was wrong and that there is not only a method that works, but one that is beautifully simple and almost foolproof.

As is so often the case, the clue had been if not under my nose, then at least above it for years, but I just did not think to look for it.

I have used the angle of the rock above ground, that is the angle that rock strata have been tilted by geological forces, many times. In the first picture you can see the rock layers, that would once have been horizontal, are now tilted from low to high as you look from left to right. Once you have tuned into the fact that the rock strata are tilted up at the southern end, it will prove a brilliant compass over wide areas of ground. Excitingly, it quickly proved to be an even better one underground.

After half an hour of exploring one of the largest slate mines in the world, descending two levels and taking many twists and turns, it was still incredibly straightforward to find the grain of the rock, look in the direction of the upwards incline and point south. Unbelievably it was easier to find direction underground than above it! In the photo of the slate wall we are looking east.

Fortunately I got a chance to escape all that by listening to Sarah’s memories of rowing, alone, across the Indian Ocean. She experienced plenty of drama as you might imagine, and this will all out in her book that is being published early next year, but the details that seized me were the ones that many others may have found prosaic.

Sarah described how the birds changed as she closed on land, how the quantity of litter grew and the formation of clouds altered noticeably. My favourite moment that day was Sarah’s recollection that all the whales she encountered were heading south. Now that is what I call a pod of wonderful compasses!

Unsurprisingly, perhaps, Sarah is not staying in the UK for too long. Her next big adventure begins soon and as she puts it, ‘I knew my next project had to involve both green and blue bits of the globe.’ There is more information about London to London: Via the World on Sarah’s website.

There were some spectacular sights as the sun rose and fought back the mist over the Arun Valley. The views were filled with colour experiments too as the pinks and oranges of the sky rose in a crescendo that battled with the whites and greens closer to the ground. In the end the orange clashed too grossly with the yellows of a field of rapeseed and I had to look away.

Yesterday afternoon I received the following email from a young navigator called Luke Hardy:

This Saturday, just gone, myself and two friends went on our local walking competition – the Charnwood Hike.  The aim is to complete the 20 mile hike in the fastest time possible. (you are allowed to run)  Unfortunately it is in the hike’s rules that we must take a map and compass.  There are various checkpoints along the route.  We were awarded points for speed and map reading- I’ve finished reading your book by now- so at the check points we showed our map reading skills to the officials, found the direction in which we had to travel (eg.SE) and, with a bit of persuasion, we put the map in David’s bag- when the officials weren’t looking- and set off looking for natural clues.  David and Sam (the two friends) were completely inspired, especially when they found that we got a better score this time than when the map was used last year. I told my two little converts that if they want to see the book they have to buy one – so there is another two sold!  I could have let them borrow it, but I have two nicknames for my copy already, “second holiest book” and “the fourth emergency service”.

What an email to receive, but take care Luke!

Anyway, flower pot time. Take a look at this photo that I took yesterday just before lunch. Note the wet ground in the shade and how the shadow of the pot has moved ‘up’ leaving a wet area in its wake. The shadow is moving west to east, away from the camera. As it is close to the middle of the day, the sun is close to south and to the right of the picture. The shadow of the young tree is a near perfect north-south line.

There is also a shadow in the pot itself, on the right, southern side. This shade is allowing one side to stay moist longer than the other, northern, side. There is more moss close to the southern edge of the pot.

This photo was actually taken eleven minutes after local midday, which is logical since it was taken in the west of Phuket and Phuket itself is in the west of the country, about 2 degrees west of Bangkok. The sun will be at its highest point over Phuket about eight minutes after it has reached its highest point when viewed from Bangkok.

Tristan


I managed to rope in a friend at the end of an evening’s BBQ and together we plumb-bobbed Polaris, set out two posts and then strung a string between them. We checked with a compass and, despite the evening’s beers, we were actually almost spot on!

The next day we checked the shadow at 1.00 (12 noon GMT) and found this lined up on our string. Impressed or what!

Richard

——————

Hi Richard,

I can see I’m going to need to come up with some sort of merit/badge/star system just to complete the back to school experience!

A link that I will have mentioned on the day is here:

http://aa.usno.navy.mil/data/docs/AltAz.php

If you plug in your latitude and longitude, it will give you the altitude and azimuth of the sun (or moon) for a whole day by GMT. Due south is often very close to clock midday, but it can wander off it depending on your longitude and because of something called the ‘equation of time’.

All the best,

Tristan

The small patch of moisture that is in the sun reveals the direction that the shadow is shortening, a crude north-south line as we near the middle of the day.

It strikes me that the world of navigation training has strayed a little off course. If you type “navigation courses” into Google you get nearly five and a half million results. I’d be prepared to wager that more than five million of these are associated with ‘traditional’ training. To my mind the majority of these are falling between two stools. They focus on using tools but not the best ones. The two ends of the spectrum are electronics and nature. Nobody, myself included, argues that natural methods are more accurate than electronics when it is working. Equally, nobody in their right mind would want to challenge someone holding a working GPS to a position-fixing competition using compass back-bearings. Where am I going with this?

Well, why do we concentrate the vast majority of our training and learning in the area that is now neither the most accurate nor the most resilient? Electronic navigation is the most accurate when it works and natural navigation cannot break. I am not suggesting that we don’t continue to learn how to use compasses and other tools that are less accurate and not immune to failure, I am just questioning whether we should have so many eggs in those baskets at the expense of natural awareness. Would we not be better off spending a small fraction of that time studying the world around us without any tools at all?