celestial navigation | Concept of celestial sphere | astro navigation | Systems of Coordinates Equatorial System | part 2

celestial navigation | Concept of celestial sphere | astro navigation | Systems of Coordinates Equatorial System | part 3

welcome to Marine Courses Center today we will complete celestial navigation & Concept of celestial sphere & astro navigation

 

Systems of Coordinates

Celestial navigation 

 

1stEquatorial System of Coordinates

 

Local Hour Angle (L.H.A)

Is the arc on the equinoctial or the angle at the pole, from the upper observer’s meridian, to the meridian of the heavenly body, measuredwestward, from 0˚ to 360˚.

Local Hour Angle (L.H.A)
Local Hour Angle (L.H.A)

Declination  (Dec.)

Is the arc on the meridian of the heavenly body, from the equinoctial, to the heavenly body, measurednorth or south, from  0 to 90˚.

 

Declination  (Dec.)

 Polar Distance (P. D)

Is the arc on the meridian of the heavenly body, from the elevated pole, to the heavenly body, measured  0˚ to 180˚.

Polar Distance (P. D)

 Component of 1st equatorial system of coordinates 

                      L.H.A and Dec. / P.D

Component of 1st equatorial system of coordinates

the relation  between  Dec.  And  P.D

  P.D  =  90    Dec         if    Lat & Dec     Same name
  P.D  =  90  +  Dec        if    Lat & Dec     Contrary name

the relation  between  Dec.  And  P.D
the relation  between  Dec.  And  P.D

Calculate the Polar Distance of the heavenly body where:
    
  Latitude of the observer 40 N, Declination of H.B  30 S
P.D  =   90  +  Dec
P.D  =   90  +  30
P.D   =   120

Parallel of Declination (Diurnal Circle)

It is the apparent daily motion of the heavenly body in the westward direction.

Parallel of Declination (Diurnal Circle)

Parallel of Declination (Diurnal Circle)

2nd  Equatorial System of Coordinates

2nd  Equatorial System of Coordinates

Sidereal Hour Angle (S.H.A)

Is the arc on the equinoctial or the angle at the pole, from the meridian      of  1stpoint of Aries, to the meridian of the heavenly body, measured westward, from 0 to 360˚.

Sidereal Hour Angle (S.H.A)
 

Right Ascension (R.A)

Is the arc on the equinoctial or the angle at the pole, from the meridian of first point of Aries , to the meridian  of heavenly body, measured Eastward from 0 to 24 hours.


Right Ascension (R.A)
 

Greenwich Hour Angle (G.H.A)

Is the arc on the equinoctial or the angle at the pole, fromthe upper meridian of Greenwich, tothe meridian of the heavenly body, measured westward, fromto 360˚.


Greenwich Hour Angle (G.H.A)
Greenwich Hour Angle (G.H.A)

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