143 lines
5.1 KiB
Python
Executable file
143 lines
5.1 KiB
Python
Executable file
#!/usr/bin/env python
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# ▄████████▄ + ███ + ▄█████████ ███ +
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# ███▀ ▀███ + + ███ ███▀ + ███ + +
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# ███ + ███ ███ ███ █████████ ███ ███ ███ ███
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# ███ +███ ███ ███ ███ ███▐██████ ███ ███ ███
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# ███ + ███ ███+ ███ +███ ███ + ███ ███ + ███
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# ███▄ ▄███ ███▄ ███ ███ + ███ + ███ ███▄ ███
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# ▀████████▀ + ▀███████ ███▄ ███▄ ▀████ ▀███████
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# + + + ███
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# + ▀████████████████████████████████████████████████████▀
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#
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# This script requires the following file in the extra/ directory:
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# https://github.com/astronexus/HYG-Database/blob/cbd21013d2bb89732b893be357a6f41836dbe614/hyg/CURRENT/hygdata_v41.csv
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import csv
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import sys
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import math
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import re
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PATH = "extra/hygdata_v41.csv"
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#def entry(ra_hour, ra_min, ra_sec, dec_deg, dec_min, dec_sec, mag, name, color_index):
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# return [
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# ra_hour*15 + ra_min*0.25 + ra_sec*0.004166,
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# dec_deg + dec_min/60 + dec_sec/3600,
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# mag,
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# name,
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# color_index,
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# ]
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#
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#
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#CUSTOM_ENTRIES = [
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# entry(0, 42, 44.3, 41, 16, 9, 3.44-15, 0.63, "Andromeda Galaxy"),
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#]
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# Lower apparent magnitude = brighter.
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# Sun = -26.7
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# Sirius = -1.44
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# Betelgeuse = 0.45
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# Polaris (north star) = 1.97
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# Meissa (orion's head, 8th brightest star in orion) = 3.33
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MAX_APPARENT_MAGNITUDE = 7.0
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SOL_ABSMAG = 4.83
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SOL_RADIUS = 696.3e6
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SOL_LUMINOSITY = 3.828e26
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STEFAN_BOLTZMANN_CONSTANT = 5.670374419e-8
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print("// This file was autogenerated by \"genrate_starchart.py\" using data from the")
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print("// HYG database: https://github.com/astronexus/HYG-Database/tree/main/hyg")
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print("// License: CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/")
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print("// Each star's values: (x, y, z, magnitude, absolute magnitude, color index, name)")
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print("[")
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def render(i, x, y, z, ra, dec, mag, absmag, ci, dist, name):
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# Takes ra/deg in degrees
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ra = float(ra)
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dec = float(dec)
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mag = float(mag)
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x, y, z = float(x), float(y), float(z)
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name = re.sub(r'\s+', ' ', name)
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if name == 'Sol':
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return
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#radius = star_radius(float(ci), float(absmag))
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# distance = 1.0
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# ra_radians = math.radians(ra * 15) # ra is in [0, 24], multiplying by 15 gives degrees in [0, 360]
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# dec_radians = math.radians(dec)
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# #print(f"ra_radians={ra_radians}, dec_radians={dec_radians}, dec={dec}, ra={ra}", file=sys.stderr)
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# x = distance * math.cos(dec_radians) * math.cos(-ra_radians)
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# y = distance * math.cos(dec_radians) * math.sin(-ra_radians)
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# z = distance * math.sin(dec_radians)
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#
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# # Correct for differences in coordinate system axes
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# x, y, z = x, z, y
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#brightness = 2.512 ** (0 - mag)
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print(f'({x:.04},{y:.04},{z:.04},{mag:.04},{absmag:.04},{ci},"{name}"),')
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def clean_name(string):
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return "".join([c for c in string if c.isalnum() or c in ' -_'])
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def star_radius(color_index, absolute_magnitude):
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# Convert color index to temperature (using Ballesteros' formula approximation for B-V)
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temp = 4600 * ((1 / (0.92 * color_index + 1.7)) + (1 / (0.92 * color_index + 0.62)))
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# Convert absolute magnitude to luminosity (in solar luminosities)
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lum = 10 ** (0.4 * (SOL_ABSMAG - absolute_magnitude))
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# Calculate the radius using Stefan-Boltzmann law (output should be in meters)
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radius = math.sqrt(lum * SOL_LUMINOSITY / (4 * math.pi * STEFAN_BOLTZMANN_CONSTANT * temp ** 4)) # Luminosity in watts for the Sun ~ 3.828e26
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# Convert radius from meters to solar radii (1 solar radius ≈ 6.96e8 meters)
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radius_solar = radius / SOL_RADIUS
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return radius_solar
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total = 0
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count = 0
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count_extra = 0
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entries = []
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with open(PATH, "r", encoding="utf-8") as f:
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for index, entry in enumerate(csv.DictReader(f)):
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entries.append((index, entry))
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entries.sort(key=lambda entry: float(entry[1]['mag']))
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for index, entry in entries:
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total += 1
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ra = entry['ra']
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dec = entry['dec']
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x = entry['x']
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y = entry['y']
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z = entry['z']
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mag = entry['mag']
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absmag = entry['absmag']
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ci = entry['ci']
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dist = entry['dist']
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name = clean_name(entry['proper'])
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if not name:
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name = clean_name(entry['bf'])
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if not name:
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name = clean_name(entry['gl'])
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if not all([ra, dec, mag, ci]):
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continue
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if float(mag) > MAX_APPARENT_MAGNITUDE:
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continue
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render(index, x, y, z, ra, dec, mag, absmag, ci, dist, name)
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count += 1
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#for entry in CUSTOM_ENTRIES:
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# render(entry[0], entry[1], entry[2], entry[3], entry[4])
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# count_extra += 1
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print("]")
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print(f"Wrote {count} stars (total={total}) + {count_extra} extra entries.", file=sys.stderr)
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