navigational astronomy :: practical astronavigation
 
Navigational Astronomy
Practical Astronavigation

Theory

1. If the theory is boring you, you can omit her, well position astro it is possible to find not having the slightest idea about the theory.
2. If you have so much perseverance in yourself that you want to know roughly, what it concerns - read far.

 

A. ESSENTIAL PRINCIPLE

 

Positional lines

 

What resemblance consists in - can see from the drawing.

1. The lighthouse is standing on the wharf, so the measurement is always the same in the same place (independently of the time).
2. Position CN there is a variable in the time, it is necessary so to have the exact time in the moment of the measurement.
3. You are as a rule very far (a few hundred miles) from the CN throw to the surface of the Earth (point CN'), so it won't be possible to draw the result on the map. It is necessary to do it differently, about what far.

 

B. NOTIONAL APPARATUS, that is what is what?

 

1. Dec. - declension (you will find in the 'Nautical Almanac').

 

Declension of the Sun

 

2. GHA - Greenwich Hour Angle - (you will find in the 'Nautical Almanac')
3. LHA - Local Hour Angle

 

 

 

 

C: AMENDMENTS, it won't be sufficient to read only

1. CHRONOMETER

Correct the tense deciphered on the chronometer according to principles:
Ch - reading of the chronometer
 +St - state of the chronometer (+ if is late, - if is in a hurry)
    Uo - time GMT
If you used the centre half, add the time to it from the centre half.

2. SEXTANT

You measured the height CN = ho
Add the constant misconception of the sextant, taken from the certificate = cc
Add the mistake of the index measured up before or after the measurement = ci
You are receiving together ho+cc+ci=hs

 

The interactive sextant

 

 

 

 

 

 

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