冲毕业第五周记录

接下来将由已经处理过的j2000转为视赤经赤纬，再转为地平坐标 J2000_x_hor。

设定时间为2022.12.10. 20：00，儒略日为2459924，经纬度为合肥{31.8642, 117.287}

int main()
{
    ifstream inFile("C:\\Users\\hp\\Downloads\\hip2.dat\\J2000_2.csv");
    ofstream outFile("C:\\Users\\hp\\Downloads\\hip2.dat\\J2000_2_hor.csv");
    cat_entry fk5;
    site_info loc = {31.8642, 117.287}; // 温度10摄氏度 高度10米 大气压1013毫巴=1013百帕

    double ra, dec, zd, az, hgmag;
    string lineStr;
    double tjd = 2459924;

    while (getline(inFile, lineStr))
    {
        stringstream ss(lineStr);
        string str;
        getline(ss, str, ',');
        fk5.starnumber = stod(str);
        getline(ss, str, ',');
        fk5.ra = stod(str);
        getline(ss, str, ',');
        fk5.dec = stod(str);
        getline(ss, str, ',');
        fk5.promora = stod(str);
        getline(ss, str, ',');
        fk5.promodec = stod(str);
        getline(ss, str, ',');
        fk5.parallax = stod(str);
        getline(ss, str, ',');
        hgmag = stod(str);
        app_star(tjd, &fk5, &ra, &dec);
        // outFile << fk5.starnumber << "," << ra << "," << dec << "," << hgmag << "\n";
        equ2hor(tjd, &loc, ra, dec, &zd, &az);
        outFile << fk5.starnumber << "," << az << "," << 90 - zd << "," << hgmag << "\n";
    }

    system("pause");
    return 0;
}

算6.5等星也只需0.131s

2等星 46个星当前时刻地平以上的有20个

3等星 165个星当前时刻地平以上的有67个

4等星 480个星当前时刻地平以上的有214个

5等星 1471个星当前时刻地平以上的有708个

6等星 4559个星当前时刻地平以上的有2219个

6.5等星 7982个星当前时刻地平以上的有3933个

目前文件夹目录下有这些文件

试试用qt显示

2等星

3等星

和下方对比差不多

4等星

5等星

画到五等星还算较快，后面就很慢了可以尝试用qpen来画

6等星

6.5等星

研究半圆球上的基准点的均匀性问题。还是很难实现，并且没有玻尔兹曼熵来作为参考，并且需要从天顶出发实时计算高度方位，当我望远镜转至该位置时，其他星点已离开螺旋基准点最终形成的星点方位高度可能不均匀。

还是决定使用全天球的螺旋基准点，并且所有恒星围绕极轴转是一个天然的性质。并且可以一次选取终生可用任意时间可用。（但这也是错的想法，并不适用于地平式望远镜选星，只适用于星敏感器的导航星筛选。

将赤经赤纬坐标转为xyz轴

以右手坐标系为例，z轴指向北极点（高度角90度），x指向东（方位角90度），y指向北（方位角0度）

极坐标转xyz轴

double x = sin(ra) * sin(dec);
double y = cos(ra) * sin(dec);
double z = cos(dec);

#include <bits/stdc++.h>
using namespace std;
string num = "2";
const double DEG2RAD = 0.017453292519943296;
int main()
{
    double ra, dec, x, y, z;
    ifstream inFile("C:\\Users\\hp\\Desktop\\hip2.dat\\J2000_" + num + ".csv");
    ofstream outFile("C:\\Users\\hp\\Desktop\\hip2.dat\\J2000_" + num + "_xyz.csv");
    string lineStr;
    while (getline(inFile, lineStr))
    {
        stringstream ss(lineStr);
        string str;
        getline(ss, str, ',');
        string starnumber = str;
        getline(ss, str, ',');
        double ra = stod(str);
        getline(ss, str, ',');
        double dec = stod(str);
        getline(ss, str, ',');
        getline(ss, str, ',');
        getline(ss, str, ',');
        getline(ss, str, ',');
        double hgmag = stod(str);

        ra *= DEG2RAD;
        dec *= DEG2RAD;
        x = sin(ra) * cos(dec);
        y = cos(ra) * cos(dec);
        z = sin(dec);
        outFile << starnumber << "," << x << "," << y << "," << z << "," << hgmag << "\n";
    }
    system("pause");
    return 0;
}

测了一下正20面体的12个顶点的玻尔兹曼熵为0

0.850650808352040	-0.525731112119134	0
0.850650808352040	0.525731112119134	0
-0.850650808352040	0.525731112119134	0
-0.850650808352040	-0.525731112119134	0
0	0.850650808352040	-0.525731112119134
0	0.850650808352040	0.525731112119134
0	-0.850650808352040	0.525731112119134
0	-0.850650808352040	-0.525731112119134
-0.525731112119134	0	0.850650808352040
0.525731112119134	0	0.850650808352040
0.525731112119134	0	-0.850650808352040
-0.525731112119134	0	-0.850650808352040

再测个足球 https://blog.sciencenet.cn/blog-2321-383987.html

.850651,0,2.327438;
.262866,.809017,2.327438;
.262866,-.809017,2.327438;
-.688191,.5,2.327438;
-.688191,-.5,2.327438;
1.701301,0,1.801708;
.52573,1.618035,1.801708;
.52573,-1.618035,1.801708;
-1.376383,.999999,1.801708;
-1.376383,-.999999,1.801708;
1.964166,.809017,1.275977;
1.964166,-.809017,1.275977;
1.376381,1.618035,1.275977;
1.376381,-1.618035,1.275977;
-.162461,2.118035,1.275977;
-.162461,-2.118035,1.275977;
-1.113517,1.809017,1.275977;
-1.113517,-1.809017,1.275977;
-2.064574,.5,1.275977;
-2.064574,-.5,1.275977;
2.389492,.5,.425326;
2.389492,-.5,.425326;
1.213921,2.118035,.425326;
1.213921,-2.118035,.425326;
.262865,2.427051,.425326;
.262865,-2.427051,.425326;
-1.639248,1.809017,.425326;
-1.639248,-1.809017,.425326;
-2.227033,.999999,.425326;
-2.227033,-.999999,.425326;
2.227033,.999999,-.425326;
2.227033,-.999999,-.425326;
1.639248,1.809017,-.425326;
1.639248,-1.809017,-.425326;
-.262865,2.427051,-.425326;
-.262865,-2.427051,-.425326;
-1.213921,2.118035,-.425326;
-1.213921,-2.118035,-.425326;
-2.389492,.5,-.425326;
-2.389492,-.5,-.425326;
2.064574,.5,-1.275977;
2.064574,-.5,-1.275977;
1.113517,1.809017,-1.275977;
1.113517,-1.809017,-1.275977;
.162461,2.118035,-1.275977;
.162461,-2.118035,-1.275977;
-1.376381,1.618035,-1.275977;
-1.376381,-1.618035,-1.275977;
-1.964166,.809017,-1.275977;
-1.964166,-.809017,-1.275977;
1.376383,.999999,-1.801708;
1.376383,-.999999,-1.801708;
-.52573,1.618035,-1.801708;
-.52573,-1.618035,-1.801708;
-1.701301,0,-1.801708;
.688191,.5,-2.327438;
.688191,-.5,-2.327438;
-.262866,.809017,-2.327438;
-.262866,-.809017,-2.327438;
-.850651,0,-2.327438