NavList:

Ross Henderson, you wrote:
"I ended up in the wrong ocean!!"

There's a famous and, even more so, horribly infamous, trillionaire who smartly believes in engineering by iteration, otherwise known as "learning from mistakes" or in the case of rockets "learning from explosions". So there's nothing wrong with ending up in the wrong ocean if we figure out how we got there. :)

In real-world navigation, I repeat a fundamental principle: you're never lost. You can always put your thumb down on a chart and say 'I'm inside this thumbprint'. How big is the thumbprint in miles?? Well, that just depends on the scale of the chart. ;) Maybe twenty miles. Maybe two hundred miles. But it's never two thousand miles. Another way of saying this is that you can always start with your "D.R." position and work from there (but it doesn't have to be a literal dead reckoning position). Celestial navigation does not determine our position on the globe; it refines it.

If you end up in the wrong ocean while analyzing a puzzle in a virtual world --also known as an armchair analysis mode-- rest assured that this would never happen in the real world. In a case with a very large error in position, bigger than that "thumb-sized" estimate of your position that you start with, you would immediately recognize that something is wrong and go back seeking an error in your work or a problem with the input data. Huge errors in position reveal themselves in the real world.

In this latest example, you're seeing Dubhe on the meridian. I don't quite agree with that, but it's a good starting point. You then look up the GHA of Dubhe for the given date and 22:53 GMT/UT and find 143° so you select 143° W as the longitude. But think about the time here... We're only an hour from 00:00 UT. We know that at 00:00 the Sun will be nearly over the global anti-meridian or 180° longitude (nearly, give or take a quarter of an hour for the equation of time). So at this time, it must be daylight near 143° W longitude. Again, in the real world, this would be instantly clear to a navigator --not so much in a virtual puzzle.

So what went wrong?

The problem with your analysis as given so far is that Dubhe is near the observer's meridian "below the pole" and that means you have to add 180° to your chosen longitude. It looks like that would put your best estimate of position in Russia, east of St. Petersburg, which is unlikely (though there are some big lakes). However, you could try my trick and shift the date of the photo from August 17 to August 27 (see my prior post). If you do that, your fix would end up in the middle of the Gulf of Finland, which might fit nicely.

To repeat, though, I don't quite agree that Dubhe is on the meridian :). It's close, so it's a good starting point nonetheless.

Frank Reed