Notes on Celestial Navigation

CNAP - Calculate an Assumed Position

Description: Calculates the Assumed Position (AP) for use with sight reduction tables and Saint-Hilaire's method.

Inputs:

GHAGHA of the celestial object
LatDR Latitude of the observer
LonDR Longitude of the observer

Outputs:

AP LatLatitude of the Assumed Position
AP LonLongitude of the Assumed Position

Sample execution:

GHA? 350,02.2
Lat? 42,32.4
Lon? 18,08.5

AP Lat: 43° 00.0'
AP Lon: 17° 57.8'

(For explanation of notation, conventions etc, see python-programs).



Copyright (C) 2024 Ian Staniforth

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.


# CNAP - Calculate an Assumed Position for Saint-Hilaire's method

from math import *
from CN_LIB import *

gha = stod("GHA? ")
lat = stod("Lat? ")
lon = stod("Lon? ")

aplat = floor(lat+0.5)

lha = (gha+lon+360)%360
e = lha-floor(lha+0.5)

aplon = lon-e

print("")
print("AP Lat: "+dtos(aplat))
print("AP Lon: "+dtos(aplon))