Fix position of the vessel from Stars & Planets

GHA Body

Greenwich Hour Angle The hour angle between the Greenwich Meridian and the meridian of a celestial body is known as the Greenwich Hour Angle. Equivalent to longitude on earth. It can be followed by East or West. The value of GHA is taken from Brown's Nautical Almanac Daily Pages entering with appropriate date and full hours time UTC.

+ SHA (Only Star)

Sidereal Hour Angle Because the fixed stars (they are not really fixed, but they are so far away that they don't seem to move much), don't move relative to each other, rather than give the GHA of each star for each hour of the day, for each day of the year, the Nautical Almanac publishes only the list of GHA for a fictitious point called "first point of Aries" (also denoted by the Zodiac sign of the Ram). The SHA of the stars is simply a coordinate relative to this point. So to calculate the GHA of a star all you have to do is: GHA(star) = SHA(star) + GHA(aries). The value of SHA is taken Almanac Daily Pages entering with appropriate date and full hours time UTC.

+/- Cv (Moon /
Planet)

Cv Correction The value of v-correction is taken from the bottom of Daily Pages of Brown's Nautical Almanac for appropriate planet for further entering and taking of the value from the Increments and Corrections table. If GHA between current time and next hour is increasing add the v Correction value

+ INCREMENT

Increment The value is taken from the Increments and Corrections table of Brown's Nautical Almanac entering with minutes and seconds of our UTC time.

GHA Calculated

+/- EP Longitude

Longitude If we have E longitude then add to GHA Calculated.
If we have W longitude then subtract.

LHA Body

Local Hour Angle LHA is the angle between the meridian of the observer and the meridian of the geographical position of the celestial body.
If LHA > 360 then subtract 360 from it.
If LHA < 0 then add 360 to it.