Your First Analysis with SNID SAGE¶
Welcome to SNID SAGE! This guide will walk you through your first supernova spectrum analysis in just 5 minutes using the GUI interface.
What You'll Learn¶
- How to load and analyze a spectrum
- Choosing the best cluster when multiple options exist
- Understanding basic results
- Simple visualization
- Next steps for deeper exploration
Get Sample Data¶
You'll need a supernova spectrum to follow along. We recommend SN 2018bfi:
- Download: SN2018bif spectrum from WISeREP
- Save: Create a
data/folder and save the file there asSN2018bif.csv - Note: This is a CSV format spectrum from the PESSTO survey
Step-by-Step Analysis¶
Step 1: Launch SNID SAGE¶

The main window opens with a clean interface ready for analysis. The toolbar at the top provides quick access to essential functions.
Step 2: Load Your Spectrum¶
- Click the "Load Spectrum" button (grey button at top)
- Navigate to your
data/folder - Select
SN2018bif.csv - Alternative: You can also drag and drop the spectrum file directly onto the plot area
- The spectrum appears in the plot area

Once loaded, your spectrum appears in the main plot area. The interface shows: - Raw spectrum in the main plot - File information in the status bar - Available actions become enabled
Step 3: Preprocess Your Data¶
- Click "Preprocessing" button (amber - now enabled)
- Right-click for "Quick SNID Preprocessing" (automatic)
- Left-click for "Advanced Manual Preprocessing" (custom settings)
- Review the cleaned spectrum

The flattened view shows the continuum-removed spectrum, making absorption and emission features more prominent. This is the direct output of preprocessing.

The preprocessing dialog shows your spectrum with preprocessing options: - Filtering: Remove noise and artifacts - Rebinning: Adjust spectral resolution - Continuum removal: Normalize the spectrum - Apodization: Smooth spectral edges
You can switch to the flux view by clicking the Flux button in the top-left corner.
Step 4: Run Analysis¶
- Click "SNID Analysis" button (magenta - now enabled)
- Right-click for default quick analysis
- Left-click for specific analysis settings
- Wait 10-30 seconds for analysis to complete

The analysis dialog shows: - Progress bar: Current analysis stage - Status messages: What's happening - Cancel button: Stop analysis if needed
- Results appear automatically
Step 5: Choose Your Cluster (If Available)¶
If SNID SAGE finds multiple viable clusters, a Cluster Selection Dialog will appear:

What you'll see: - 3D Interactive Plot: Shows all clusters in redshift vs type vs correlation space - Cluster Dropdown: Click "▼ Select Cluster" in top-left to see all options - Top Matches Panel: Right side shows spectrum overlays for the selected cluster - Automatic Selection: Best cluster is pre-selected (marked with BEST)
How to choose: - Hover over clusters to highlight them - Click on any cluster to select it - Use dropdown to see all clusters with their types and redshifts - Review matches in the right panel to see template quality - Click "Confirm Selection" when satisfied
Tips: - Best cluster is usually correct - the automatic selection is reliable - Check the matches panel - better template overlays indicate better classification - Close dialog to use automatic selection if unsure - Multiple clusters often indicate ambiguous cases (e.g., II vs TDE)
Understanding Your Results¶
The analysis provides a clear classification:

This view shows your spectrum overlaid with the best-matching template: - Your spectrum (blue line) - Best template (red line) - Match quality indicators - Redshift information

The summary provides: - Top matches with scores - Spectral classification - Redshift estimates - Confidence levels
Final classification: - Type: Main supernova type (e.g., II, Ia, Ib, Ic) - Quality: High/Medium/Low confidence level - Subtype: Detailed classification (e.g., IIn, IIP, norm)
Measurements: - Redshift: Determined redshift with uncertainty - Age: Days from maximum light with uncertainty
Template matches: A ranked list of best matching templates showing: - Template name and type - HσLAP-CCC score (final metric) - Individual redshift and age estimates

This plot shows: - Redshift distribution across templates - Age estimates for different redshifts - Confidence regions - Best-fit parameters

The subtype analysis reveals: - Detailed classifications - Subtype proportions - Template contributions - Classification confidence
Basic Visualization¶
- Zoom: Mouse wheel or box selection
- Pan: Click and drag
- Reset View: Double-click
- Toggle Views: Switch between flux and flattened views
Quick Tips¶
- Keyboard Shortcuts:
Ctrl+O- Load spectrumCtrl+Enter- Quick preprocessing + analysis- Button Colors: Grey → Amber → Magenta → Purple (workflow progression)
- Status Bar: Check for progress updates and messages
CLI Analysis (Alternative Method)¶
Prefer the command line? The CLI produces identical results with a single command:
Common options:
sage data\SN2018bif.csv --output-dir results\ --complete # All outputs + plots
sage data\SN2018bif.csv --output-dir results\ --minimal # Summary only
sage data\SN2018bif.csv --output-dir results\ --forced-redshift 0.02435
sage data\SN2018bif.csv --output-dir results\ --type-filter Ia II
| GUI | CLI |
|---|---|
| Interactive cluster selection | Automatic selection |
| Step-by-step workflow | Single command |
| Display + files | Files only |
See the CLI Reference for all options.
Next Steps¶
Now that you've completed your first analysis, explore:
- GUI Complete Guide - All interface features
- CLI Reference - Command-line interface
- AI Features - AI-powered analysis
Need Help?¶
- Buttons disabled? Follow the workflow: Load → Preprocess → Analyze
- Poor results? Check signal-to-noise and wavelength coverage
- More help: See Troubleshooting
Congratulations!¶
You've successfully completed your first SNID SAGE analysis! You can now: - Load and analyze supernova spectra - Interpret basic classification results - Use the GUI interface effectively - Generate basic visualizations
Ready for more? Check out our GUI Complete Guide for advanced features and techniques.