The natural Navigation: The Right Course, Naturally

Another very enjoyable Beginner’s Guide to Natural Navigation course at the Royal Geographical Society yesterday. The diversity of interests and experiences never fails to amaze me; from desert wanderers to cruise ship sailors and even a sailor from a tall ship in the Pacific. Wonderful!

It was a beautiful full moon last night and I got to experiment with a new lens that I have bought. Still a long way to go until I take a photo of the moon that I am happy with, but always learning which is satisfying.

The phase of the moon appears the same all over the world, but the orientation changes depending on your latitude. In other words, a full moon will be full all over the world, but its features may appear upside down from the opposite hemisphere. When high in the sky, crescent moons will appear closer to ‘vertical’ at higher latitudes and ‘horizontal’…

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…with a little help from the sun.

An interesting article on the BBC website today about the seasonal habits of Puffins.

The most interesting thing other than learning more about the puffins’ whereabouts was the method they used for understanding where the birds were at any one time. Using ‘geolocator tags’ that logged the time of sunrise, sunset the research team were able to deduce their location.

‘The loggers work by measuring light levels, recording when dawn and dusk occurs each day.

With this data, researchers can calculate day length, when midday occurs, and the daily longitudinal and latitudinal co-ordinates for the individual bird.’

The tags also detected when the birds’ feet were wet, the hope being that this would give information about when the birds were airborne, but the puffins foxed the researchers here: they like to tuck their feet up into their plumage when asleep. Their feet were dry even as they bobbed on…

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Last night, looking west through some tree branches, I took this picture of the orange star, Arcturus. It is one of the five brightest stars in the night sky and is part of the constellation Bootes. It is in fact the brightest star in the northern half of the celestial sphere.

It is navigationally interesting because of its declination or ‘celestial latitude’. At 19 degrees north it passes overhead a lot of major cities, including Honolulu, Mumbai and Mexico City.

The easiest way to find Arcturus is to follow the the handle of the Plough on its curved path away from the ’saucepan’. The star that can just be seen in the top right of the photo is the end of the saucepan handle.

I took this photo in St Peter Port, Guernsey, about ten days ago. This big fat gin palace probably doesn’t get lost very often, all they need do is squint at the setting sun through their ice cold sundowners, think about the season and latitude, then wait for the blue to turn black and the stars to appear. Or they could just turn on one of the many lovely gizmos sprouting all over the top of the boat. GPS would do it, radar would too, or they could make a satellite call and ‘phone a friend’.

Sticking with a midsummer theme for another day, I came across this picture today. It was taken in a place called Uttakleiv in northern Norway. The time lapse shows how the sun does get lower, the angle being directly related to the latitude, but at this high latitude even its lowest point is not below the horizon. I was fortunate enough to witness the midnight sun in Kiruna in north Sweden a few years ago, but my photos were a lot less dramatic than this. Something to do with the fact I had flown about ten hours that day in a tiny aircraft. That and the fact that I am not a very good photographer.

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

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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…

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Last night I spent a few minutes re-reading a couple of passages from Barry Cunliffe’s book about Pytheas the Greek. About 2300 years ago Pytheas went seriously far north for a Mediterranean, but the debate still rages about how far he went. Some of it seems to revolve around an expression about there being enough light to ‘pick the lice from your shirt’ at midnight. Now that’s what I call natural.