How to find compass error


Azimuths are tabulated from North or South towards East or West. Amplitudes are tabulated from East or West from North or South.

Step 1 – Observe suns bearing on the celestial horizon note it with the time of observation.

Step 2 – We will have to find the time in GMT so that we can use the time in Nautical Almanac.

Step 3 – Find Declination, (if the value is increasing, the d correction is to be added otherwise subtracted.)

Step 4 – Find LHA

Step 5 – Compare observed azimuth to calculated azimuth. Compass Error is the difference between the two values.

Tan Z = (( Cos DEC ) (Sin LHA)) / ((( Cos Lat ) ( Sin Dec )) – (( Sin Lat) ( Cos Lat )( Cos LHA)))

If LHA is More than 180 than it is entered as negetive. If Dec and Lat are contrary name,Dec is entered as a negetive. If Z is negetive add 180 degrees.

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