Import stars in blender

import csv
import bpy
import colorsys

# Compute the color of a star from its color index:
# see https://stackoverflow.com/questions/21977786/star-b-v-color-index-to-apparent-rgb-color
def bv2rgb(bv):
    r,g,b = 0,0,0
    #extrema and out of range values
    if (bv<-0.4):
        bv=-0.4
    if (bv> 2.0):
        bv= 2.0
    #red
    if bv>=-0.40 and bv<0.00:
        t=(bv+0.40)/(0.00+0.40)
        r=0.61+(0.11*t)+(0.1*t*t)
    elif bv>= 0.00 and bv<0.40:
        t=(bv-0.00)/(0.40-0.00)
        r=0.83+(0.17*t)
    elif bv>= 0.40 and bv<2.10:
        t=(bv-0.40)/(2.10-0.40)
        r=1.00
    #green
    if bv>=-0.40 and bv<0.00:
        t=(bv+0.40)/(0.00+0.40)
        g=0.70+(0.07*t)+(0.1*t*t)
    elif bv>= 0.00 and bv<0.40:
        t=(bv-0.00)/(0.40-0.00)
        g=0.87+(0.11*t)
    elif bv>= 0.40 and bv<1.60:
        t=(bv-0.40)/(1.60-0.40)
        g=0.98-(0.16*t)
    elif bv>= 1.60 and bv<2.00:
        t=(bv-1.60)/(2.00-1.60)
        g=0.82-(0.5*t*t)
    #blue
    if bv>=-0.40 and bv<0.40:
        t=(bv+0.40)/(0.40+0.40)
        b=1.00
    elif bv>= 0.40 and bv<1.50:
        t=(bv-0.40)/(1.50-0.40)
        b=1.00-(0.47*t)+(0.1*t*t)
    elif bv>= 1.50 and bv<1.94:
        t=(bv-1.50)/(1.94-1.50)
        b=0.63-(0.6*t*t)
    return [r,g,b]

#Create one star
def createBlenderStar(x,y,z, col,mag):
    #create an icosphere
    bpy.context.scene.cursor_location = (x,y,z)
    bpy.ops.mesh.primitive_plane_add(radius=0.2)
    #add the vertex color
    mesh = bpy.context.active_object.data
    vertexColour = mesh.vertex_colors.new()
    faces = mesh.polygons
    for d in mesh.vertex_colors[0].data:
        d.color = col

#Delete everything but the earth
"""
bpy.ops.object.select_all(action="SELECT")
bpy.data.objects["Earth"].select = False
bpy.ops.object.delete(use_global=False)
"""

#Path to the csv file
starFile = "/home/loic/Downloads/hygdata_v3.csv"

#Read in the 1000 first stars
reader = csv.DictReader(open(starFile))
for i, row in enumerate(reader):
    if i<1000:
        x = float(row["x"])
        y = float(row["y"])
        z = float(row["z"])
        mag = float(row["absmag"])
        col = bv2rgb(float(row["ci"])) if row["ci"]!="" else [0.8,0.8,0.8]
        createBlenderStar(x,y,z,col,mag)
        print(i)

#Assign the emissive/vertex color material
for o in bpy.data.objects:
    if o.name!="Earth" and o.type=="MESH":
        #assign the material
        mat = bpy.data.materials.get("Material")
        if o.data.materials:
            o.data.materials[0] = mat
        else:
            o.data.materials.append(mat)