🟥SUBJECT: GYRO ERROR SAMPLE COMPUTATION Here’s a sample calculation for finding the gyro error. I usually use an Excel calculator for quick results, but it’s also good to review the manual method. Knowing both helps you stay sharp and well-rounded in navigation. =========== Sample calculation (Azimuth-Sun): On 09th of May 2006 at 05h 30m 00s UTC, a vessel in position 55° 00'N & 002° 00'W observed the Sun bearing 073° by magnetic compass. Find the compass error. If variation is 5 W, calculate the deviation. Declination (09d 05h) N 017° 19.2' d(0.7): (+) 00.4 ___________________________________ Declination Sun: N 017°19.6' ============================= GHA Sun (09d 05h) 255°53.2' Increment (30m 00s) 007°30.0' ___________________________________ GHA Sun: 263°23.2' Longitude (E +/ W-) 002°00.0' ___________________________________ LHA Sun: 261°23.2' P= 360-261°23.2'= 98°36.8' (If LHA > 180°, P=360-LHA) A = Tan Latitude/ Tan P A = Tan 55 00‟/ Tan 98 36.8‟ A = 0.216327037 N (A is named opposite to latitude, except when hour angle is between 090 and 270 ) B = Tan Declination/ Sin P B= Tan 017°19.6'/ Sin 98°36.8' B = 0.315534702 N (B is always named same as declination) C = A+B = 0.531861739 N (C correction, A+/- B: If A and B have same name- add, If different name- subtract) Tan Azimuth = 1/ (C X Cos Latitude) = 3.278007549 Azimuth = N 73.0 E (Azimuth takes combined name of C correction and Hour Angle- If LHA is between 0 and 180 , it is named “west”, if LHA is between 180 and 360 , it is named “east”) True Azimuth= 73.0° Compass Azimuth= 73.0° Compass Error = NIL Variation = 5.0° West Deviation = 5.0° East - @onlinethirdmate