Quote:
Originally Posted by ColinS
I am new to this and it dont seem so easy.
I live in Rockingham W.A. and want to find true south. I have been to the Government site shown above and it gives me a reading of -4.634, however, someone else told me that I should point my compass due magnetic south and then the true south would be 12 degrees to the east of that. If the declination says -4.634, is that the difference, or 12 degrees. Is the -4.634 degrees or some other measurement.
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Place Names Search Results
NAME STATE FEATURE CODE STATUS LAT (DD MM) LONG (DD MM) ELEVATION (m)
ROCKINGHAM WA LOCB (Towns & Localities) Official -32 16 115 43 -
Australian Geomagnetic Reference Field Computation
Requested: Latitude -32o 16' 00", Longitude 115o 43' 00", Elevation 0 km, Date 2011/01/1
Calculated: Latitude -32.2667o, Longitude +115.7167o, Elevation 0.00 km, Epoch 2011.0000
Magnetic Field Components
D = -1.833 deg
Therefore your accurate, compensated magnetic compass will be pointing about 1.8 deg west of true north. Equally 1.8 deg east of true south. That should be within the azimuth adjustment range of any GEM if you were to start with the mount aligned on magnetic south.
If your tripod is steel or there is any steel fences/reinforcing/tanks/etc nearby, it will affect your compass.
Andrew