hertzsprung.py

import matplotlib.pyplot as plt
from matplotlib.colors import LogNorm
import csv, math
import numpy as np

mag = []
bprp = []

with open('files/combined2.csv', 'r') as f:
    table = csv.reader(f)

    firstLine = True
    
    for row in table:
        if firstLine:
            firstLine = False
            continue
        try:
            parallax = float(row[9])
            apparent_magnitude = float(row[50])
            absolute_magnitude =  apparent_magnitude + 5 - 5 * (1 + math.log10(1/parallax))
            colour = float(row[55])-float(row[60])
            mag.append(absolute_magnitude)
            bprp.append(colour)           
            
        except:
            pass

print("Number of stars: ", len(mag))

plt.hist2d(bprp, mag, bins=3500, norm=LogNorm(), cmap="plasma")

plt.ylabel(r"Mean Absolute Magnitude (mag)")
plt.xlabel("Mean BP Mag - Mean RP Mag (mag)")

#plt.xscale("log")
plt.colorbar()
plt.ylim(28, 0)
plt.xlim(-2,6)
#plt.gca().invert_yaxis()

plt.savefig("hertzprung_russell_alldata_colour_hist3.png")
plt.show()