Scribd
Upload
87 views3 pages

1.1. Daily Page: GHA, Dec For Hour of Observation and D'

The document summarizes the steps taken to calculate the compass error from observational data taken on 26 Feb 2018 at 22:45 UTC. [1] The GHA, declination, and other data were obtained from the Nautical Almanac. [2] The LHA, declination, and azimuth were calculated using the Nautical Tables. [3] The true bearing was calculated as 262.2 degrees, while the observed gyro bearing was 262 degrees, indicating a 0.2 degree error to the east. [4] The magnetic compass error of 15.8 degrees west and deviation of 4.4 degrees west were then determined.

Uploaded by

sara
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
87 views3 pages

1.1. Daily Page: GHA, Dec For Hour of Observation and D'

The document summarizes the steps taken to calculate the compass error from observational data taken on 26 Feb 2018 at 22:45 UTC. [1] The GHA, declination, and other data were obtained from the Nautical Almanac. [2] The LHA, declination, and azimuth were calculated using the Nautical Tables. [3] The true bearing was calculated as 262.2 degrees, while the observed gyro bearing was 262 degrees, indicating a 0.2 degree error to the east. [4] The magnetic compass error of 15.8 degrees west and deviation of 4.4 degrees west were then determined.

Uploaded by

sara
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 3

COMPASS ERROR

Date: 26 Feb 2018 Gyro: 108°

Time (UTC): 22:45:00 Magnetic: 124°

Lat: 12°00.5’ N Variation: 11.4W

Long: 068°51.1’W Observed BRG: 262°

1. Nautical Almanac (NA). Requires the GHA, Dec and ‘d’ of the Sun on 26th Feb 2018.

1.1. Daily Page: GHA, Dec for hour of observation and ‘d’

1.2. Increments and corrections: GHA correction for minutes and correction for ‘d’(d corr. – when Dec deacreasing)
1.3. Calculation of GHA and Dec

GHA Dec d

Daily page 26 Feb 2018; 22:00 UTC 146°48.0’ 8°28.4’S 0.9

Increments for 45min 00sec 11°15.0’

‘d’ correction -0.7’

Sum for 26 Feb 2018 22:45:00 UTC 158°03.0’ 8°27.7’S

1.1. Calculation of LHA (Local Hour Angle)

LHA = GHA + Long. (- for W, + for E)

LHA = 158°03.0’ + (- 068°51.1’)

LHA = 089°11.9’

2. Norie’s Nautical Tables (A B C Azimiuth tables)

2.1. Table A is entered with LHA and Lat, name opposite to the Lat., except when the LHA is beetwen 90° and 270°

2.2. Table B is entered with LHA and Dec, always named the same as the Dec
2.3 Table C is entered with Lat and calculated C as below:

If A & B have the SAME name, C = (A+B) and C takes the name of A & B

If A & B heve DIFFERENT names, C = (A ˜ B) and C takes the name of A or B, whichever is the larger.

2.4 Calculating Azimuth

The Azimuth is N or S depending on the name of C and E or W depending on the value of LHA

(E if the LHA is between 180° and 360°. W if the LHA is between 0° and 180°)

A = 0.0

B = 0.14 S

C = 82.2

Azimuth = S82.2W

True BRG = 180° + 82.2°

True BRG = 262.2°

3. Calculating gyro compass error

True BRG 262.2°

Observed BGR 262.0°

Gyro error 0.2E

4. Calculating error and deviation of magnetic compass

Magnetic 124.0°

Gyro 108.0°

Gyro error 0.2°E

Magnetic error 15.8°W

Variation 11.4°W

Deviation 4.4°W

You might also like