As so often seems to be the case, a short stroll from the mainstream channels uncovered rough diamonds.

In the programme, an aerial shot showed us clearly visible patterns in the earth, patterns that were partly concealed at ground level by dense undergrowth. The narrator explained that we were looking at ‘geoglyphs’ in the Amazon rainforest. Geoglyphs are shapes that have been deliberately formed in the land by the hand of man.

Like many pilots, I have come to love the way it is possible in the air to spot patterns in the earth that are hard to notice on the ground. Lines that are lost in their surroundings on terra firma, stand out luminously from 3000 feet. But my experience has been restricted to European Iron Age Hill Forts and the like. This was definitely new territory.

In the Amazon there are ‘negative’ geoglyphs, formed by digging ditches, often up to 4m deep – ‘negative’ only in the sense that something has been removed. In other parts to the world there are positive geoglyphs where shapes are formed by building up from the ground, using stones or similar.

You can imagine that my ears pricked more than a little when the anthropologist being interviewed, explained that the hundreds of shapes they had found in the Amazon were mostly aligned north-south. A little light digging of my own revealed this to be a far-from isolated example, many of the worlds geoglyphs are aligned with the cardinal points.

This is definitely not coincidental. The most likely explanation for geoglyphs, even when the exact explanation is elusive – as in the Amazon, is that there is a religious/spiritual explanation for these mammoth land sculptures. Once more there is the temptation to ask the question: “How did these old and technologically-basic civilisations manage to create architecture on near-perfect north-south lines.” This question is quite natural, but it is to misunderstand one important part of the ancient world: the sky.

Historically, most divine worship has looked upwards and outwards at least a little. The sky forms part of many ancient cultures’ creeds. From here it is simply a case of realising that the way the sky appears to behave and the directions we know as north, south, east and west and just two sides of the same coin. Anyone who spends time admiring the patterns in the day and night sky will come to know north, south, east and west, even if they use different words, because these are labels for the changes we see in the sky. East and west are the average directions of sunrise and sunset, wherever you are in the world, and north and south are the anchors of the night sky – the only two places where the stars cease their restlestness, the world over.

In the picture above we are looking at a geoglyph called the Paracas Candalabra in Chile. It is aligned almost perfectly north-south and can be seen from miles out to sea. There are a few more very good examples of geoglyphs here.

A False Temptation

I cover the idea above from a similar angle in my book, The Natural Navigator:

“There is sometimes a temptation to think that this is all a remarkable coincidence: how extraordinary that the sun should happen to sit neatly on certain lines, like north or south, at certain times, or that it should happen to rise exactly east or set west at others. It is, however, a false temptation, because the cardinal directions and the motion of celestial objects, including the sun, are just different ways of looking at the same thing…”

The astronomical explanations for all of the above can be found in the simple, and yet rich and revealing, revolution of the Earth on its axis and its orbit around the sun. Geoglpyhs are aligned with respect to the axis of the Earth’s rotation. Not because its architects were aware of such a motion, but because the sky betrays it.

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!

We started with theory indoors at the offices of Outward Bound Oman, with the help of planetarium software and makeshift whiteboards (paper Sellotaped to a cupboard). After three hours of theory, it was time to head out in 4x4s for a 3 hour drive into the desert, for some more practical training.

We tracked the sun down to the horizon and confirmed that it had indeed set a good 15 degrees south of west. We looked at the way the wind had shaped some small plants and then how the crescent moon was pointing perfectly south. After some dahl and rice it was time to sit on the mats on the sand and get apply the astronavigation theory to the night sky. Jupiter beamed brightly from the east.

At a latitude of 23 degrees and at that time of year the Plough is too low to use, so we focused on Cassiopeia. I also pointed out the Navigator’s Triangle and the way the ‘cross’ of Cygnus can be used to find north. The final method we used was the square of Pegasus. More importantly we studied the movement of the stars, before settling in for an early night.

The following morning there was too much cloud cover for stars so we packed up and got ready to make the most of the early morning cool for some daytime exercises. Picking my mat up off the sand I was confronted with the realisation that I had been sleeping over an unwelcome guest: a scorpion (see photo below). This was the first of many encounters in 48 hours. (That night, I felt a tickle on my foot as I went for a pee and a flash of the headtorch revealed that worse than poor aiming, it was another good-sized scorpion crawling over my foot. Like hornets and other unwelcome ‘friends’, scorpion sightings are fortunately much more frequent than scorpion stings, which remain rarer and much less deadly than their reputation. That was hopefully of some comfort to Gary Lyon, a consulting instructor, who was sleeping nearest me and received a nasty scorpion sting on his foot. He was much more stoical about the whole thing than I would have been!)

We spent the morning looking at clues in the sun, the dunes, the trees, the wind and clouds. Then we did some exercises in gauging distance using paces and perspective.

We sat out the midday heat in the shade, which gave me a chance to have a really fascinating discussion with Eric Staples. Eric is an authority on medieval Arabic navigation, he has personally overseen the rebuilding of many historical Omani sailing vessels and has a passion for historical Arabic navigational techniques. Together we spent a wonderful couple of hours trying, successfully I believe, to unlock some secrets in a Arabic text regarding the use of the Pole Star by reference to the lunar mansions. It was great teamwork, Eric’s knowledge of medieval Arabic is of the highest order and my familiarity with some of the techniques they referred to helped us solve some tricky passages. Great fun, but not for the faint-hearted!

Later that day we were able to use a ‘kamal‘ that Eric had fashioned from traditional materials of wood and twine. This simple instrument was used by the earliest sailors and desert travellers as a means of establishing latitude. More on that another time.

I also was privileged to spend time with Dr. Andrew Spalton, the leading conservationist authority in Oman.

On the final morning at 5am we enjoyed good sightings of Orion, Leo, Mars, Gemini, Procyon, Taurus, Pleiades and a whole host of others. We used Capella and Auriga to find north. As the sun rose, 15 degrees south of east, it was sadly time to go.

My heartiest thanks to Mark Evans at Outward Bound Oman for inviting me to Oman and to his instructors for the patience and enthusiasm. What a country!

In the photo at the top we are looking north along linear sand dunes. These dunes form when two complementary winds channel the sand into long, often dependable dunes. The winds had clearly blown more from the southeast than the southwest, as the eastern flank was the firm shallower windward side and the western side was the softer steeper slip-face.

I’m just back from a week’s holiday with my wife on the Greek island of Kefalonia. It was our first holiday without the kids for about seven years, which felt bizarre from start to finish. This is the only, admittedly weak, excuse for the navigational lapse that ensued.

In Fiskardo, at the northern end of Kefalonia, we hired a small day-boat and spent many mornings motoring up and down the east coast of Kefalonia. We pursued the not very stressful business of hunting quiet bays and seeking secluded beaches for a swim.

On the fifth morning we putt-putted all the way round the northern Kefalonian coast to a beach at the northern tip of the island called, Dafnoudi beach.

We had spent almost all of the week on the east coast of the Kefalonia looking across the water, to the east, and seeing the beautiful Ithacan coastline.

After a quick swim at Dafnoudi we decided to head across to Ithaca, the land of Odysseus, and explore the beaches there. It was a little over 3 miles to the northern promontory of Ithaca, but I only know this now because I have researched it and I only researched it because we nearly didn’t get there. Yes, I know, there is a better order to researching journeys and undertaking them, but Greek islands have such a wicked way of mixing our ideas concerning being careless and being carefree.

Almost all small boat journeys in hired boats are done by line-of-sight navigation in these waters, from one landmark to the next. No proper charts, no compasses, no GPS. The distances are small and the visibility is usually pretty good.

On the late morning in question, the visibility was actually quite poor, a languid mist hugged the sea and the lower land. The photo above should give a fair taste of how the sea, land and sky like to merge a little in these conditions.

About five minutes after setting off two things in quick succession made me realise my massive and embarrassing mistake. The first was that I became subconsciously (through a feeling of unease) and then consciously aware that the sun was not where I was expecting it. I had grown used to seeing and feeling it dominate the southern half of the landscape as we pottered south, east and west. The only time we ever headed north for any serious time was when motoring back home from a foray to a southern beach.

The problem was that we were supposed to be heading east to Ithaca and yet the sun was nowhere to be seen. It should have been peeking below the canopy to my right and roasting my right cheek. It was not. What’s more I suddenly realised that I could feel it on the back of my neck.

This sudden dawning – I should say ‘near-middaying’ – made me scour the mist soaked land ahead with much keener interest than I had before. Then I saw a lighthouse where I was not expecting to see one.

‘Oh my God!’ I said out loud.

‘What’s wrong?’ My wife asked, with a voice that suggested that she did not want to know too many details if we were in serious danger.

‘We’re heading for completely the wrong island. We’re heading towards Lefkada!’

Lefkada is another neighbour of Kefalonia, but it is north of the island, not east, and at least another mile further away.

I corrected our course by a mere 100 degrees and half an hour later we were swimming on a beautiful deserted Ithacan beach. It was a bonus that this beach was deserted as I needed time to let my blushes subside.

An excerpt from his account of his travels is a good reminder of how much better connected the travellers of old were to the incestuous relationship between the sun, time and direction.

We hurried into the town where we were to change
horses, but our haste was fruitless. There we were obliged to wait
until our baggage came up long, long after us, and until it was
adjusted upon fresh cattle. If we now had galloped all the way to
Lhasa the sun would have been in the south before we could have
been in the august presence of the Tagin. This was exceeding
discomfort to my Munshi, but great comfort to me. I much dis-
liked the idea of hurrying to Lhasa, and without any kind of
refreshment going before the mandarins, sweltering and heated, my
boots hurting me every step I set; and I could not comprehend
what crime it was for travellers like us who could not command
prompt attendance, arriving an hour sooner or an hour later.

In winter full moons rise north of east, in summer they rise south of east. They rise further from east the nearer we get to the solstices. The full moon always behaves in the opposite way to the sun, in time and direction, as it is opposite the sun in its cycle.

Fire rainbows (see photo) are very rare and form in cirrus ice crystals at high altitudes; their coloured arcs are near horizontal and parallel to the horizon. Fire rainbows can only come into being if the sun and atmospheric conditions meet very stringent criteria, another of nature’s beautiful balancing acts. There is more background to these extraordinary light shows on the National Geographic website.

As this website explains, fire rainbows can only occur when the sun is high enough in the sky (58 degrees or more) and sadly that rules them out from highish latitudes like the UK for most of the year.

At nine minutes past three this morning, GMT, the sun was overhead the equator.  To celebrate, here are a few things that you may or may not know about the equinox. Only one of them is not true.

The sun will rise due east and set due west for everyone today.

The direction (bearing) of sunrise and sunset changes by more each day at this time of year than at any other time.

On the December side of the equinoxes the sun is always overhead the southern hemisphere, on the June side it is always overhead the northern hemisphere.

Everyone on the planet shares an equal length day and night on the equinoxes.

Satellites that appear stationary and stay over the same spot on the Earth’s surface are called geostationary or geosynchronous and they remain in orbit over the equator. As the sun passes over the equator at the equinoxes, it passes behind these satellites and can cause interference in telecommunications.

Many of the world’s religions observe the autumnal equinox, including the Druids and the Native American tribe, the Chumash.

Eggs can be balanced on their end on the equinoxes.

The sun, trees, churches, clouds and satellite dishes all played their parts, but there are so many lesser known roles in the epic production that is ‘City Navigating’.

As if to prove this I received a message a couple of days ago from someone who had read the book and got in touch with some intriguing urban ideas. Clem McEwen drew my attention to two methods which sounded familiar, but which are certainly not well known to me, or used by me… yet!

1) Street numbering. Streets are normally numbered in ascending order away from the centre of a town, with the numbers 1 and 2 being closest to the centre, normally on opposing sides of the street.

2) The crossbars on telephone poles are always on the side nearest Charing Cross in London.

Both of these seem strangely familiar and yet, like so much of the navigation experience, are not things that I have been consciously aware of recently. I do have vague recollections of my mother mentioning the Charing Cross idea when I was a child, but then again she was much more likely to have been giving me some variant of her standard navigational advice: ‘Drink lots of water and wear a vest if it’s white outside!’

The final act of my Grand London Foray was a three mile traverse that clipped a corner of Hyde Park; it went without a hitch, but then Hyde Park is an obscenely large and easily recognised landmark.

I have not yet had a chance to research the methods sent over by Clem in any detail, practically or theoretically, but if anyone has any light to shed on them or experience in using them, then please drop me a line.

Marcus is sculpting a series of ‘tidal bells’ that will ring out at high tide around the country. There is no mention of springs or neaps in the article, so I’m presuming the bells are being placed low enough to ring at a neap tide (the narrowest range between high and low).

In the book I touch on the fact that humans have become very adept at approximating tidal behaviour, but it is still impossible to predict tidal times or heights with absolute precision. The tides are influenced by the orbits of the Moon about the Earth of course, but also very significantly by the orbit of the Earth around the Sun, which fewer people realise. These are the factors that are relatively easy to predict. The effects of wind, air pressure, temperature and the motion of the previous tide’s water are harder to predict and this chain continues almost all the way down down to the flap of a butterfly’s wings in Australia.

Technical challenges of predicting tides aside – these bells are not being designed to replace Caesium clocks in laboratories – it is a beautiful concept and I can’t wait to hear a bell ring out. Regular blog readers will know that I get an intense pleasure whenever creative works embrace the natural world and this is accentuated when there is a navigational connection. My thanks to Angela Williams for bringing my attention to the story and best of luck to Marcus in his work.