Preprocessing (GUI)

How to prepare spectra before analysis.

Quick SNID Preprocessing

  • Purpose: Minimal steps to prepare a spectrum for SNID.
  • Actions: log rebinning, optional smoothing, apodization, continuum handling.
  • When to use: Most cases; fastest path to classification.

Manual Preprocessing

  • Open via: Preprocessing → Manual wizard

  • Steps (subset; tooltips in dialog):

  • Input and range

  • Wavelength range (wmin, wmax): leave blank for auto
  • Smoothing
  • Savitzky–Golay window (savgol_window): 0 disables; typical 11–21
  • Savitzky–Golay order (savgol_order): default 3
  • Telluric and sky features
  • Remove A-band (aband_remove): masks ~7600–7650 Å
  • Sky line clipping (skyclip)
  • Emission line clipping redshift (emclip_z): -1 disables
  • Emission width (emwidth, Å)
  • Apodization
  • Apodize percent (apodize_percent): typical 5–15%
  • Masks
  • Custom wavelength masks: e.g. 6550:6600 7600:7700

Best practices

  • Inspect S/N before aggressive smoothing
  • Prefer specific masks over broad ranges
  • Keep apodize_percent modest to preserve edges

CLI parity

GUI options map to sage flags:

sage spectrum.dat --output-dir results/ \
  --savgol-window 11 --savgol-order 3 \
  --aband-remove --skyclip \
  --emclip-z 0.02 --emwidth 40 \
  --wavelength-masks 6550:6600 7600:7700