Monday, September 13, 2010

The Navigation Lesson


  •  Navigate One of the things I am most keen to do is to learn celestial navigation. Not out of a desire  to keep a dying art alive but out of my Big Chicken Baby tendency to think of every possible dire scenario and how I would handle it. What will we do if the chart plotter fails and all of our GPS aids are lost because an errant sea gull is attracted to the shiny bits and flies off with them?!?!? My answer- navigate by sextant, watch and charts. Of course at this point in time, I have no idea how to use a sextant but we will get there.

    Mark is one of those folks who can quickly grasp a concept at face value, examine it and perfect it. I have a capable enough intellectual capacity, but I also possess this wacky brain which thrives on tangential “rabbit chasing”. To his credit, Mark just takes my weirdo thought processes in stride and soldiers onward. Here’s an example.

    Mark and I were sitting at the dining room table after dinner with the globe. We do this from time to time to think about where we might like to travel. This time, Mark was going to start my navigation lessons. It went something like this:

    Mark: Ok, there are 360 degrees in a ….
    Me: Circle
    Mark: Right. The Earth is a circle and therefore it has 360 degrees but in navigation parlance, the prime meridian or 0 is at Greenwich England.
    Me: Why did they pick Greenwich? Nobody goes to Greenwich. London makes more sense. They should just say London.
    Mark: Greenwich is home to the Royal Observatory and since the British Admiralty developed all the charts they get to choose the prime meridian.
    Me: I wonder how the Spanish feel about that. They’re probably just a bit bitter.
    Mark:  We aren't concerned with how the Spanish might or might not be feeling, lets move on. With Greenwich being 0 degrees longitude, the Earth is measured in 15 degree increments going to 180 degrees East or 180 degrees West.
    Me: Why do they do that?
    Mark: Why do they do what?
    Me: Reuse the numbers, only going to 180 .Wouldn't’t it make more sense to count all the way to 360 rather than reusing numbers and confusing people by having a 30w and a 30E? That sounds like they were being obstinate just to confuse people.
    Mark: No,  they weren't being obstinate, they were…never mind. You understand, yes?
    Me: Yes.
    Mark: Ok, each degree of longitude is divided into 60 minutes and further divide into 60 seconds.
    Me: Why do they call it minutes and seconds? That makes no sense.
    Mark: Yes, it does. They have to call it something and since early navigation utilized chronometry minutes and seconds it was.
    Me: So really the minutes and seconds mean nothing, just a means of measurement?
    Mark: Yes, you could call it anything so long as the measurement was precise.
    Me: So we could call it degrees, door knobs and doughnuts?
    Mark: Umm..
    Me: Doughnuts would be a good name. That would make me hungry though. Then I’d crave carbs. Carbs are the devil.
    Mark: (places head in hands) What ever, do you understand so far.
    Me: yes, I understand perfectly. I still think the Spanish are probably bitter about the Greenwich thing though.


  1. I love it!! Sounds like how one of our "lessons" go down around our house too. Thank goodness our men have a lot of patience! I'm happy to hear that I"m not the only one whose mind goes to worse case scenario, maybe it's a Mom thing ~ safety first!!

  2. GPS is the same as celestial only using man made *stars* which send out electrical signals instead of photons.

    It's just trigonometry YUCK and taking an accurate sight and having a precise clock. I took a class at the planetarium and practiced for a season with my Davis Sextant... and used it in the Marion Bermuda race... but it's gathering dust in a locker. GPS is quite reliable and cheap and I have 3 or 4 of them now.