Wednesday, June 6, 2018
Basic Training - Basic Celestial Navigation
Don't panic or go crazy. The celestial navigation we're going to use is only the most basic.
If you don't have a compass, knowing the cardinal directions (that's North, South, East, and West for Common Core grads) is enough for starters.
If you want to learn greater detail than that, plot the constellations, define your latitude or find noon with a sextant, ROWYBS; you'll have to take a much more in-depth course. It's beyond the scope of a class for basic training, but feel free on your own time to go deeper.
What we're concerned with, quite simply, is finding North, or South.
In the Northern Hemisphere, assuming a clear night sky and basic intelligence, you do two things.
You find Ursa Major, i.e. the "Big Dipper". (And for Brits, "The Plough".)
Then you take the two stars that form the far lip of the dipper opposite the "handle", follow them in the direction they align for about 5½ times as far as they are apart, and you come to Polaris, in Ursa Minor, aka the "Little Dipper".
From wherever you're standing in the Northern hemisphere, straight down to the horizon from that point is due north.
Once you know North, you can figure out East, West, and South.
You can do the same thing in reverse in the Southern Hemisphere (because you can't see Polaris from there) by finding the Southern Cross.
Absent a compass or protractor and map, anything else is navigation by guess and by God, and pretty rough indeed.
Beyond that, the sun and moon both rise in the East, and both set in the West.
How far North or South of directly East and West is a function of the season, and your actual latitude on the globe.
And the moon rotates on a roughly 28+ day cycle: there is a full moon every four weeks, and a new moon (blacked out) the same span apart, 14 days later. People who don't pay attention should know that the moon starts appearing on the right side of the crescent, and fills out from right to left, then disappears in the same way. So if you didn't know before, know you know whether the moon's getting bigger ("waxing") or smaller ("waning"), and again by calibrated eyeball, you know how many days until it's full, or dark ("new").
On cloudy nights, you're S.O.L. for any of this.
For basic wayfinding though, it could be enough to get you pointed in the right direction. Or headed away from a bad one.