AstroColor

A Python library for converting between photometric systems, true color calculation, and space image processing.

It performs synthetic photometry on low-resolution (5-nm wavelength grid step) spectra as well as spectral reconstruction from measurements in filters based on Tikhonov regularization.

Pre-alpha version! Do not use!

Installation

Use AstroColor in a virtual environment:

python3 -m venv .venv
.venv/bin/pip install git+https://github.com/Askaniy/AstroColor.git

Or add AstroColor to your uv project:

uv add git+https://github.com/Askaniy/AstroColor.git

Key features

• Calculate synthetic photometry

import astrocolor as ac

spectrum = ac.Spectrum(
    wavelength_nm=[400, 500, 600, 700],
    spectral_dist=[1, 2, 2, 1]
)
v_band = ac.Filter.get('Generic_Bessell.V')
flux_value, flux_error = ac.observe(spectrum, v_band)

• Create a filter system

johnson_system = ac.FilterSet.get(
    'Generic_Bessell.B',
    'Generic_Bessell.V',
    'Generic_Bessell.R'
)
photospectrum_BVR = ac.observe(spectrum, johnson_system)

• Reconstruct photometry measurements into a smooth spectrum

reconstructed = ac.spectral_reconstruction(photospectrum_BVR, requested_wavelengths=[400, 700])

• Convert measurements directly between photometric systems

sloan_system = ac.FilterSet.get('SLOAN_SDSS.g', 'SLOAN_SDSS.r')
photospectrum_gr = ac.observe(photospectrum_BVR, sloan_system)

• Work on your wavelengths

custom_filter_set = ac.Filter.monochromatic(656.279) | ac.Filter.monochromatic(486.135)

• Calculate true colors

color_xyz = ac.ColorPoint.from_spectral_data(ac.sun_CALSPEC)
color_system = ac.ColorSystem('sRGB', 'Illuminant E') # recommended
color_rgb = color_xyz.to_color_system(color_system)
color_rgb.maximize_brightness = True
color_html = color_rgb.to_html()

• Model spectra

bb_3000K = ac.BlackBodyModel(3000).determine_at_wavelengths([400, 700])

• Process images via spectral cube reconstruction

# coming soon after debugging

• Error propagation with covariance matrices

# coming soon after debugging

History

TrueColorTools were created in 2020 to resolve disputes regarding the color of celestial bodies. It features a graphical user interface and a user-expandable spectral database. Over time, the core of the program became self-contained enough to be spun off into a library. The refactoring took place in 2026; it opens up a general astronomical application.

For developers

Use uv sync --group dev to set the environment and build the library. Use uv run pytest for testing. Use \dev folder for local experiments.

Any changes suggested by AI must be thoroughly reviewed by the person who generated them. The responsibility always lies with the person.