Rough Science and position finding

[Paul]

I've been trying an experiment in basic navigation over the last week whilst staying at Coningsby, Lincolnshire. (53°06'33"N and 0°10'11"W)

Its the one where the television program Rough Science used a protractor to measure the height of the pole star and a radio, watch, and sundial to work out your latitude.
The weather didn't help (poor sun, plenty of rain) but I eventually managed to set up a sundial and find solar midday.

By using the protractor and a bit of fishing line, I measured the angle to the north star.
Nearest I could get was 53°.
That's the easy part. The longitude is the hard bit.
In 1 minute the world turns 360º / 24hr x 60 mins or ¼ of a degree.

Once I had worked out solar midday with my sundial, all I did was count the number of seconds from solar noon till the long pip happened at 1 pm. (Remember because of British Summer time GMT is one hour behind)

57 seconds (I minute as near as damn it). So my longitude was 0 degrees, 15 minutes West (long pip came after solar noon).

So my Rough Science position was 53°N 0° 15' W

Using a thing called a great circle calculator at http://www.movable-type.co.uk/scripts/latlong.html, I found that I was only 17 km (10 miles) off.

Not brilliant you're thinking but a heck of a lot better for a search team flying a box search to find you.

Go one, try it. It's a bit of fun.

[Skean Dhude]

Paul,

Sounded great up o the pips bit. If you need that then you can't do it without technology. What can you replace the clock with to make it something we can use after an event?

[Paul]

Time is always the critical thing when measuring longitude.
Rough science talks of time keeping using a pendulum to keep time, but the whole system falls down without a calibrated local or GMT noon signal.
Using a sextant, star fixes, and a good up to date almanac is an alternative. BUT even then the tabulated reading are roundups/downs of maths so all have errors. Besides, when learning to sail I tried a sextant. Nearest consistant accuracy I could get was 1/2 a degree or 2 minutes longitude time.

Having said that, total destruction of all comms gears seems a bit unikely.
After all what would be the use of prepping?????
I've made a trench radio before. Dead easy except for the blueing of the razor blade and getting my pencil sharp enough to get the detector to run sweetly (never could get a safety pin to work!). THat enabled me to listen to the 200khz Rugby Transmission and a host of MF stations.
I've got to believe some automated transmitter on LF or even MF will be running.
If nothing is, why would you need to locate yourself anyway.
My goal was to learn the ability to aid a search party to my location. If there is no technology ANYWHERE, what's the point is calling for help???

[Skean Dhude]

Well it is not just having a working transmitter. It is having a working transmitter that gives the time. Most stations get the time from Rugby so when Rugby stops either is destroyed or runs out of power we will lose that capability.

As to why do you need to locate yourself. In our situation you are rprobably ight we are never far from somewhere we can use to define our location but eventually we will end up somewhere out in the wilds and we will need to find out where we are. Then as we start to explore the new world we will. So not as much at the start but in the long term.