Magnetic South position lost.

[Pinwheel]

Hi Gang, Well I have had to do some painting & carpentry on the sundeck where I also use my telescope at night. Anyway I painted over my tripod marks for true South/North. So my question is this "As true north & magnetic north degrees differ, does the same applies to South + or -" ?
This time around I will drill some marks in the deck as to not loose my position.:shrug:

[koputai]

Yep, true North is 180^ away from true South, just as magnetic North is 180^ away from magnetic South.

Cheers,
Jason.

[Pinwheel]

Yes we know that but what about Magnetic veriance is it + or - how many degrees?

[GeoffW1]

Hi,

In your area it is +10 deg 0 sec, ie East of true North.

This means that when you turn around and face South, magnetic South will be 10 deg West of true South, and therefore the SCP, or to the right as you see it. You would therefore place the compass pointer on 170 deg, and note the position of true South on the scale at 180.

http://www.iceinspace.com.au/forum/showthread.php?t=15990

Cheers

[Pinwheel]

Thanks Geoff, I roughly thought that but needed clarification..

[koputai]

Isn't that what I said?

[mithrandir]

That's not necessarily true. The line joining the magnetic poles does not have to pass through the centre of the earth. It will be close, but not 180 degrees away.

Hang a plumb bob on the deck. Mark the shadow at local solar noon. This will be exactly N/S. Solar-Noon (http://www.solar-noon.com/) (and various other programs) will calculate the time for you for every day of the year.