SDSS F Star Spectra Visualization

A Python toolkit for downloading and visualizing stellar spectra from the Sloan Digital Sky Survey (SDSS) Data Release 18, focused on F-type stars with effective temperatures around 6500 K.

Live Demo

• Interactive Sky Map - Explore star positions, hover to see spectra
• Spectrum Gallery - Browse all spectrum plots

Features

Spectrum Plots

• Publication-quality plots with labeled spectral absorption lines
• Major features marked: Balmer series (Hα, Hβ, Hγ, Hδ), Ca II H & K, Na D, Mg I b
• Color-coded line markers by element type
• Noise panel showing flux uncertainty (σ = 1/√ivar) vs wavelength
• Stellar parameters displayed: Teff, log g, [Fe/H], coordinates, S/N

Interactive Sky Map

• Plotly-based HTML visualization of star positions (RA vs Dec)
• Points colored by metallicity [Fe/H] using Viridis colorscale
• Hover over any star to see its full spectrum as a popup
• Proper astronomical convention (RA increases right-to-left)

Requirements

• Python 3.9+
• numpy
• matplotlib
• astropy
• plotly

Usage

Generate spectrum plots for all FITS files:

/opt/miniconda3/envs/py39/bin/python plot_spectra.py

Generate the interactive sky map:

/opt/miniconda3/envs/py39/bin/python sky_map.py

Output

• spectrum_plots/ - PNG plots for each spectrum
• spectrum_plots/index.html - Gallery view of all spectra
• sky_map.html - Interactive sky map with spectrum popups

Data

The dataset contains 100 F-type stars from SDSS DR18 with:

• Effective temperature: Teff ≈ 6500 K
• Surface gravity: log g ranging from ~2.2 to ~4.4
• Metallicity: [Fe/H] from -3.1 to 0.0
• Signal-to-noise: 10 to 111

Stellar parameters are stored in spectra_metadata.json and were obtained from the SDSS Stellar Parameter Pipeline (SSPP).

File Structure

├── plot_spectra.py        # Spectrum plotting script
├── sky_map.py             # Interactive sky map generator
├── spectra_metadata.json  # Stellar parameters (Teff, log g, [Fe/H], etc.)
├── spec-*.fits            # SDSS spectrum FITS files
├── spectrum_plots/        # Generated PNG plots
│   └── index.html         # Gallery view
└── sky_map.html           # Interactive sky map

License

MIT