Magnetic North vs. True North

Newbie question here. I know there is a difference between Magnetic North and True North. I have been told that my Tempest needs to be aligned with True North. According to the NOAA Magnetic Declination Estimated Value calculator, my declination value is 0 degrees 52’ east +/- 22’, changing by 0 degrees 5’ west per year. My question is this. How far to the left of Magnetic North do I turn my Tempest base to set for True North or am I over thinking this?

My iPhone compass app has a setting to change to True North.

yes you are overthinking it. of course it should be as precise as possible and rotate the 52’, but this is so small nobody will notice. However in other places it can be a lot more. Have a look at

I aligned mine with the polar star.


Each degree is 60’ so you are less than a degree off. As @sunny said, you are over thinking it. If you don’t have a compass app which can show true North, try a magnetic one or use the satellite view of a map like Google or Bing maps and find some reference true North of your location and use that to align your Tempest.

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This web site explains some options to find true North.
cheers Ian :slight_smile:

the title suggests it only works for true south :wink: :wink:

Thanks everyone. I figured I was overthinking the deal. Since I am using part of the mounting for my old system and it has North already marked on it, I will recheck the North alignment, put my Tempest up and call it all good.