Calculating Variation on AutoPilot

[Bop]

Hoping someone can help me calculate/understand my magnetic variation (v A r) setting on my ST60 auto pilot. I have calculated my variation/declination as show below using the NOAA calculator with my lat/long coordinates.

Date Declination
2021-06-06 9° 28' W ± 0° 24' changing by 0° 1' E per year

Where I am getting confused with whether this 9°W is a plus or minus (+/-) input. Reading online i am seeing the following:

By convention, declination is positive when magnetic north is east of true north, and negative when it is to the west.

Am I West of magnetic north or is West of me?

Anyone have any experience with this?

 

[Alhuriyah]

Google the Agonic Line. It should show you where you are in relation to True North. E/W.

 

[mquiet]

True heading plus variation in your case is W (+) equals magnetic heading. Minus Eastern deviation will equal your magnetic course on your boats compass.

 

[Bop]

True heading plus variation in your case is W (+) equals magnetic heading. Minus Eastern deviation will equal your magnetic course on your boats compass.

Thank you. So would I not be inputed -9 degrees since "Magnetic North" is "West" of me?

 

[fr8dog]

Handy way to remember. East is least (minus) and West is best (plus).

 

[Bop]

Handy way to remember. East is least (minus) and West is best (plus).

That is a great saying thanks. However, I still am not clear, does "East is least" mean it is east of me, or I am east of it? On the chart below, I have circled my location for perspective.

 

[ttmott]

This guy does the best job explaining.

 

[nealtrombley]

Handy way to remember. East is least (minus) and West is best (plus).

ahh pilot training school

 

[fr8dog]

That is a great saying thanks. However, I still am not clear, does "East is least" mean it is east of me, or I am east of it? On the chart below, I have circled my location for perspective.
View attachment 106741

Using your chart you can see your location is between 5 West and !0 West. West is best, so you would add the number.

 

[Bop]

This guy does the best job explaining.

Thank you, that is a fantastic video!

 

[hughespat57]

That is a great saying thanks. However, I still am not clear, does "East is least" mean it is east of me, or I am east of it? On the chart below, I have circled my location for perspective.

here is what your asking and none of the maps so far are not showing.
True north is the North geographic Pole, Magnetic North is geographically in northern Canada

So if you were anywhere on a line that went thru BOTH the North Pole and Magnetic North Pole your compass would point true North and Magnetic North at the same time (zero Deviation)
You are currently standing East of that line, the adjustment is West 9 (+9)

Why? Because we reference True North, so if you want TN you have to add 9 degrees.
TN becomes MN + 009 you steer 009M to be heading TN

 

[Bop]

here is what your asking and none of the maps so far are not showing.
True north is the North geographic Pole, Magnetic North is geographically in northern Canada

So if you were anywhere on a line that went thru BOTH the North Pole and Magnetic North Pole your compass would point true North and Magnetic North at the same time (zero Deviation)
You are currently standing East of that line, the adjustment is West 9 (+9)

Why? Because we reference True North, so if you want TN you have to add 9 degrees.
TN becomes MN + 009 you steer 009M to be heading TN
View attachment 106770

Thank you. So the easy way to view is that if the Agonic line is West of me, I add the degrees, if the Agonic line is East of me, I deduct the degrees. Does that make sense?

 

[hughespat57]

east is least, west is best you got it...

 

[Bop]

east is least, west is best you got it...

Thanks for your (and everyone's) help!

 

[swaterhouse]

I cant wait until the magnetic poles flip again, we are way overdue for one!

 

[mquiet]

That is a great saying thanks. However, I still am not clear, does "East is least" mean it is east of me, or I am east of it? On the chart below, I have circled my location for perspective.
View attachment 106741

So looking at the diagram and where you circled...if you know true heading then add the West variation to get magnetic heading then deviation to get compass heading. If you are using your compass first, then add in the deviation which gives you magnetic course and then subtract the variation to find true heading.

 

[alnav]

A couple more nmemonics:
"Can Dead Men Vote Twice At Elections?"
"Timid Virgins Make Dull Companions, Add Whiskey"
Probably only familiar to those who had maritime services air or sea navigation training.

Then there's: "Ho Mo To" - related to celestial navigation but probably too politically incorrect to be used these days, but not for the reason you think.