add create LSST filters script

#!/usr/bin/env python3

# Author: Akke Viitanen

# Email: akke.viitanen@helsinki.fi

# Date: 2026-02-06 12:34:02

"""

Create the LSST filters in EGG format

"""

import glob

import astropy.units as u

import fitsio

import numpy as np

# filename_in  = sys.argv[1]

# filename_out = sys.argv[2]

# NOTE: git clone 'https://github.com/lsst/throughputs.git'

if __name__ == "__main__":

    filenames = glob.glob("data/egg/share/filter-db/inaf/throughputs/baseline/hardware_*.fits")

    for filename_in in filenames:

        x, y = np.loadtxt(filename_in).T

        x *= u.nm.to(u.um)

        norm = np.trapz(y, x)

        y /= norm

        assert np.isclose(np.trapz(y, x), 1.0)

        filename_out = filename_in.replace(".dat", ".fits")

        fitsio.write(filename_out, {"LAM": np.array([x]), "RES": np.array([y])})