NewtonianVignetting.java

package com.clarke.agnes.experiments;

import java.util.ArrayList;
import java.util.List;

/**
 * Calculates the vignetting caused by the size of the Newt secondary and the f ratio.
 * Units are mm.
 * Created by Ags on 5/12/2015.
 */
public class NewtonianVignetting {

    public static void main(String[] args) {
        double aperture = 250.0;
        double fRatio = 5.2;
        double[] secondaries = {46.0, 50.0, 63.0, 70.0};
        double focusser = 45.0;
        double tubeGap = 30.0;

        List<List<String>> columns = new ArrayList<>();
        ArrayList<String> fieldStop = new ArrayList<>();
        columns.add(fieldStop);
        fieldStop.add("Field Stop");
        for (int i = 0; i < 100; i++) {
            fieldStop.add(""+i);
        }

        for (double secondary : secondaries) {
            ArrayList<String> col = new ArrayList<>();
            col.add(""+secondary);
            columns.add(col);
            double mirrorRadius = aperture / 2.0;
            double secondaryRadius = secondary / 2.0;
            double d = mirrorRadius + tubeGap + focusser;
            double focalLength = aperture * fRatio;
            double coneWidth = d / fRatio;
            double fiftyMmField = 50.0 * (focalLength - d) / focalLength;

            double secondaryDist2 = secondaryRadius * secondaryRadius;
            double coneDist2 = coneWidth * coneWidth / 4.0;

            System.out.println("d = " + d);
            System.out.println("aperture = " + aperture);
            System.out.println("secondary = " + secondary);
            System.out.println("coneWidth = " + coneWidth);
            System.out.println("fRatio = " + fRatio);
            System.out.println("focalLength = " + focalLength);
            System.out.println("fiftyMmField = " + fiftyMmField);

            boolean first = true;
            double centerVal = 0.0;
            for (double ii = 0.0; ii <= 50.0; ii += 0.5) {
                double i = ii / 50.0 * fiftyMmField;
                double count = 0.0;
                for (double x = -mirrorRadius; x < mirrorRadius; x += 0.1) {
                    for (double y = -mirrorRadius; y < mirrorRadius; y += 0.1) {
                        double distFromSecondaryCenter = (x * x) + (y * y);
                        double distFromConeCenter = ((x + i) * (x + i)) + (y * y);
                        boolean onSecondary = (distFromSecondaryCenter <= secondaryDist2);
                        boolean inCone = (distFromConeCenter <= coneDist2);
                        if (onSecondary && inCone) {
                            count++;
                        }
                    }
                }
                if (first) {
                    first = false;
                    centerVal = count;
                }
                double v = count / centerVal;
                System.out.printf("%.2f: %.2f: %.2f\r\n", ii, i, v);
                col.add(""+v);
            }
        }
        System.out.println();
        System.out.println("---------------------------------------");
        System.out.println();


        for (int i = 0; i < 100; i++) {
            for (List<String> column : columns) {
                System.out.print(column.get(i) + ',');
            }
            System.out.println();
        }

    }

}