Naval Procedure:

 

Daily Procedure:

 

1)      Calculate the morning nautical time (MNT) from the nautical almanac the night before.

    This is the time when we take our readings.

2)      At 45 min before MNT, recognise and identify the celestial bodies and fill up the table under Calculated.

3)      At MNT, measure the altitude of the celestial bodies and fill up the data under the Observed section

 

 

For example:

 

Serial No.

Stars/Planets

Calculated

Observed

Bearing

Sextant alt.

Gyro Bearing

Sextant alt.

D.W.T

1

Betelgeuse

43.1

66o 04.8í

 

-

-

2

Canopus

160.6

43 o 41í

 

44 o 45.4í

05 18 24

3

Jupiter

42.3

45 o 20í

 

49 o 53.6í

05 28 22

4

Sirius

106.2

61 o 21.5í

 

68 o 18.2í

05 30 37

5

Formalhaut

241

6 o 37.8í

 

-

-

 

Table of the commonly used 57 navigation stars for observation

 

 

A pictorial representation of the bearing and altitude of the stars with respect to the ship.

The largest circle represents the altitude 0 o .The middle circle represents the altitude 30 o

and the inner circle represents the altitude 60 o. The point above the ship represents 90 o.

 

4)      Using the sunís course to map out location on earth

         A position plotting chart is needed to find out the ship's direction and the ship's eventual course.

 

Time

Event

Sunrise

Measure sunís bearing

0830

Measure morning sunís altitude

1000

Calculate morning sun and plot Observed position (Sun Run Sun)

1115

Prediction of merpass of the sun

Merpass-15min

Measure merpass sunís altitude (Sun Run Merpass)

1400

Measure afternoon sunís altitude and bearing (Merpass Run Sun)

1530

Sun Run Sun

Sunset

Measure sunís bearing

 

5)      Predict the Evening Civil Time (ECT)

6)      Identify the stars 15 min before ECT

7)      At ECT, measure the altitude of the celestial bodies

8)      Prepare the next dayís MNT

 

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