如何用 Python 绘制中国古代星图 (IV)

原创已于 2025-09-18 07:33:59 修改 · 385 阅读

3 ·

CC 4.0 BY-SA版权

文章标签：

#python #开发语言 #matplotlib

于 2025-09-17 20:58:43 首次发布

西方星座边界图

为了绘画西方星座的边界图以供对比，你需要以下几项：

星座名称：清楚列出你想要绘制的所有西方星座的名称。
星座边界信息：找到每个星座的边界坐标相关资料，以确保绘制的准确性。
绘图工具：可以使用专业的绘图软件（如 Python matplotlib 绘图包)。

例如：中国的太微垣约在西方的室女座与狮子座之间。

图1：中国的太微垣

图2: 西方的88个星座

绘画西方星座边界程序：

# constellation_boundaries.py
def dd2dms(dd):
    is_positive = dd >= 0
    dd = abs(dd)
    minutes,seconds = divmod(dd*3600,60)
    degrees,minutes = divmod(minutes,60)
    degrees = degrees if is_positive else -degrees
    return (str(degrees)+":"+str(minutes)+":"+str(seconds))

def dms2dd(degrees, minutes, seconds):
    is_positive = degrees.find('-')           # is_positive = -1 if positive
    dd = abs(float(degrees)) + float(minutes)/60 + float(seconds)/(60*60);
    dd = dd if  is_positive == -1 else -dd
    return dd

def deg_ra(hms):
    parts = hms.split(':')
    lon = dms2dd(parts[0], parts[1], parts[2])
    return (lon*15)

def deg_dec(dms):
    parts = dms.split(':')
    lat = dms2dd(parts[0], parts[1], parts[2])
    return (lat)

import matplotlib.pyplot as plt

fig = plt.figure(1, figsize=(64, 40))
plt.clf()  # 清画布

# 加入赤纬标志
positions =[60,50,40,30,20,10,0,-10,-20,-30,-40,-50,-60]
labels = ["60°","50°","40°","30°","20°","10°","0°","-10°","-20°","-30°","-40°","-50°","-60°"]
plt.yticks(positions, labels)

# 加入赤经标志
positions = [360, 330,300, 270, 240, 210, 180, 150, 120, 90, 60, 30, 0]
labels = ["0h", "22h", "20h", "18h", "16h", "14h", "12h", "10h", "8h", "6h", "4h", "2h", "0h"]
plt.xticks(positions, labels)

# 绘画黄道
import ephem
eclx_values  = []
ecly_values = []
for d  in range (0, 361, 2):
    m = ephem.Ecliptic(dd2dms(d),"0")             # 黄道 long 和 lat
    equ = ephem.Equatorial(m)                     # 转变为赤道 ra 和 dec
    # 找出对应的赤道座标系 x,y
    x = deg_ra(str(equ.ra))
    y = deg_dec(str(equ.dec))
    eclx_values.append(x) 
    ecly_values.append(y)     
    # 每15度加一标记及寫上黄道经度
    if  d % 15 ==0:
           plt.annotate(str(d), (x, y), ha='center', size=6)
           plt.plot(x,y, "|", color = "green")
plt.plot(eclx_values, ecly_values, color="green", linestyle="dashed", linewidth=1)

# 绘画西方星座边界
ra_cst=[];dec_cst=[]
old_cst = "AND"      # 由室女座开結
with open("const_boundaries.txt", "r", encoding="utf-8") as filestream:
    next(filestream)                                          # 跳过第一行
    for line in filestream:
        currentline = line.split(";")                         # 分隔符是分号
        if currentline[2].strip() == old_cst:                 # 同一星座?
           ra_cst.append(float(currentline[0]))               # 是, 放在同一列表内
           dec_cst.append(float(currentline[1]))
        else:
           # 否则是新的一个星座
           # 先画之前的星座
           plt.plot(ra_cst, dec_cst, color="green", linestyle="dotted", linewidth=0.2)
           # 新的一个星座, 先清列表
           ra_cst = []
           dec_cst = []
           ra_cst.append(float(currentline[0]))
           dec_cst.append(float(currentline[1]))
           old_cst = currentline[2].strip()                 # 更新星座名称

# 写出星座简称
import constellation_names
constellation_names.write_text(plt)

plt.xlim(360, 0)                # x 轴反方向
plt.ylim(-62,62)                # y 轴
axes=plt.gca()                  # 长宽比
axes.set_aspect(1)              # x/y  = 1
axes.grid()                     # 加入格线

plt.tight_layout()
plt.show()

星座边界的数据可以在以下网站找到:
https://cdsarc.cds.unistra.fr/viz-bin/cat/VI/49

VI/49 星座边界表的格式：RAJ2000;DEJ2000;cst;type

该表列出了星座边界的赤经 (RAJ2000) 和赤纬 (DEJ2000)，星座名称 (cst)，type I 代表插入值，type O 代表原有值。

RAJ2000;DEJ2000;cst;type
353.035698;+35.1897736;AND ;I
352.027387;+35.1880264;AND ;I
351.018963;+35.1860695;AND ;I
350.010539;+35.1838989;AND ;I
349.002342;+35.1815186;AND ;I
347.994003;+35.1789322;AND ;I
346.985692;+35.1761322;AND ;I
345.977554;+35.1731300;AND ;I
344.969329;+35.1699181;AND ;I
344.465304;+35.1682358;AND ;O
344.460181;+36.1682281;AND ;I
344.454889;+37.1682205;AND ;I
344.449482;+38.1682091;AND ;I
344.443932;+39.1682014;AND ;I
共有 12948行。

在星图上写出星座名称的程序：

#constellation_names.py
def write_text(plt):
    # 星座位置: RA, DEC, 星座名称: Const_abbreviation
    cst_names =  [355, 36,   "And", 9, 22,     "And", 39, 41,     "And", 154, -39.5, "Ant",
                  358, -22,   "Aqr", 314, -14, "Aqr", 292, -11.5, "Aql", 260, -47,    "Ara",
                  47, 11,      "Ari", 95, 32,    "Aur",  227, 8,      "Boo", 73, -46,    "Cae",
                  58.8, 53.2,"Cam", 310, -27,"Cap",110,-52.5,  "Car", 22, 51,     "Cas",
                  359, 51,    "Cas",   225,-32,"Cen",173, -56,   "Cen",322, 56,    "Cep",
                  20,-19.5,   "Cet",  50, 7,     "Cet", 110,-33,   "CMa", 118, 0.3,   "CMi",
                  132, 8,     "Cnc", 95, -42,   "Col", 202, 15,   "Com", 276, -45,   "CrA",
                  246, 27,   "CrB",177,-8,     "Crt", 184,-57,   "Cru", 192,-13,      "Crv",
                  195, 32,    "CVn",325, 32,  "Cyg", 312, 3,    "Del",  67, -49.8,   "Dor",
                  283, 48,    "Dra", 225, 55.5,"Dra",320, 3,    "Equ", 65, -2,        "Eri",
                  33, -57.5, "Eri",  36, -26,   "For",112, 13,   "Gem",346, -38,   "Gru",
                  268, 21,   "Her", 63.5, -41.3,"Hor",143, 5,   "Hya" ,  215, -24, "Hya", 
                  320, -47,  "Ind", 342, 36,    "Lac", 165, 12,  "Leo", 89, -26.5,   "Lep",
                  237, -9,    "Lib", 159, 28.5, "LMi", 239, -31, "Lup",132, 34,      "Lyn",
                  99, 54.5, "Lyn",  285 ,27,  "Lyr",  320, -29.5,"Mic", 105, -9.5, "Mon",
                  247, -44,  "Nor", 259,-29.5, "Oph", 274, 13,  "Oph",  94, -3,     "Ori",
                  342, 3,    "Peg", 2.5, 20.5, "Peg", 66, 32,    "Per",   28, -42,   "Phe",
                  358, -41, "Phe",  89, -46,    "Pic",  346,-26, "PsA",  12, 10.5,  "Psc",
                  349, -3,   "Psc", 125, -22,   "Pup",140, -26, "Pyx",  59, -55,    "Ret",
                  25,  -26,   "Scl", 359, -26,   "Scl", 260, -32, "Sco",  282, -15,  "Sct",
                  233, -3,    "Ser", 274, -15,   "Ser", 162, -11, "Sex", 291, 18,   "Sge",
                  295, -32,  "Sgr",  67, 11,     "Tau", 285, -47, "Tel",  28,  32,    "Tri",
                  148, 42,   "UMa",216, 55.5, "UMa",165, -42,  "Vel", 213, -19,  "Vir",
                  316, 20.5, "Vul"]
    
    for i in range(0, len(cst_names), 3):
        plt.text(cst_names[i], cst_names[i+1], cst_names[i+2], color="#1f77b4", fontsize=8)

运行结果：