Frequently Asked Questions

AstroIndexer is a comprehensive astrophotography management and analysis application. It indexes your FITS and XISF files, measures quality metrics (FWHM, HFR, SNR, eccentricity) with PixInsight-grade accuracy, discovers patterns with 6 Imaging Intelligence modules, and helps you plan imaging sessions with a full-lifecycle planner.

AstroIndexer runs on:

• Windows 10 and later (64-bit)
• macOS 12 (Monterey) and later (Apple Silicon & Intel)
• Linux Ubuntu 22.04+ and compatible distributions

Full support: FITS (.fits, .fit, .fts), XISF (.xisf), TIFF (.tif, .tiff)

Partial support: RAW formats (CR2, NEF, ARW) via dcraw, JPEG, PNG (limited metadata)

Extension matching is case-insensitive, so .FIT, .Fits, .XISF all work. Compatible with files from N.I.N.A, SGPro, APT, Voyager, Seestar S50, ASIair, and other capture software.

No. AstroIndexer never modifies your original image files. It only reads metadata from files, creates thumbnails in its own directory, and stores analysis results in its local database. Your images remain untouched.

Windows: Download the installer (.exe), run it, and follow the wizard. You can choose both the install location and the data directory.

macOS: Download the .zip, extract, and drag AstroIndexer to Applications. On first launch, right-click → Open to bypass Gatekeeper.

Linux: Download the .tar.gz archive, extract, and run the included launcher.

This is normal for newly downloaded software.

• Windows SmartScreen: Click "More info" then "Run anyway"
• macOS Gatekeeper: Right-click the app → Open, or go to System Settings → Privacy & Security → "Open Anyway"

• Windows: %LOCALAPPDATA%\AstroIndexer\
• macOS: ~/Library/Application Support/AstroIndexer/
• Linux: ~/.local/share/AstroIndexer/

The database (astro_indexer.db), thumbnails, and configuration are stored in this directory. On Windows, the installer lets you choose a custom data location.

Yes. AstroIndexer can catalog images on any accessible drive (USB, NAS, network share). The drive must be connected for viewing and analysis, but thumbnails are cached locally for offline browsing. If drive letters change, use "Update Paths" to reconcile.

FWHM (Full Width at Half Maximum) measures star diameter in pixels. Lower values mean sharper stars and better focus/seeing:

• Excellent: < 2.0 px
• Good: 2.0 – 2.5 px
• Acceptable: 2.5 – 3.0 px
• Poor: > 3.0 px

Note: these are general guidelines. AstroIndexer scores frames relative to your own equipment's typical performance, not fixed thresholds.

The quality score (0–100) is a weighted combination of four metrics:

• FWHM (40%) — star sharpness (lower is better)
• SNR (30%) — signal-to-noise ratio (higher is better)
• Star Count (20%) — number of detected stars (optimal range)
• Eccentricity (10%) — star roundness (lower is better)

Scoring bands: Reject (<30), Needs Work (30–50), Ready (50–75), Good (75–90), Exceptional (90+).

AstroIndexer's Quality Analysis uses Moffat PSF fitting and produces FWHM, HFR, eccentricity, and SNR measurements that are within ~5% of PixInsight SubframeSelector values. It processes frames in batch automatically, whereas SubframeSelector requires manual setup per session.

Common reasons:

• Image has no stars (clouds, daylight, calibration frames)
• Extremely out of focus (no detectable star shapes)
• Very short exposure (insufficient signal)
• Corrupted file data

Calibration frames (darks, flats, bias) are automatically detected and skipped.

AstroIndexer includes 6 specialized Imaging Intelligence modules:

1. Environmental Patterns — correlates quality with temperature, humidity, altitude
2. Exposure Optimization — recommends sub-exposure times based on your equipment and conditions
3. Sensor Heatmap — maps quality across your sensor to find vignetting, dust, aberrations
4. Session Analysis — identifies quality trends within and across imaging sessions
5. Pattern Predictions — predicts quality based on conditions
6. AI Insights — generates personalized improvement recommendations

Plus a Stacking Advisor that recommends optimal frame selection for each target.

Imaging Intelligence becomes increasingly useful as your library grows. Basic patterns emerge with 100+ analyzed frames. Environmental correlations and equipment recommendations are most accurate with 500+ frames across multiple sessions and conditions.

Every imaging project moves through 5 states:

1. Queued — on your wishlist, not yet configured
2. Planned — equipment, framing, exposure plan, and goal hours set
3. Scheduled — has specific night blocks on your calendar
4. Active — currently being imaged
5. Completed — imaging goal reached

Yes. The Session Planner can export projects as N.I.N.A sequence files, including target coordinates, exposure plans, and filter sequences. Set up your project in AstroIndexer, then export and load in N.I.N.A for automated imaging.

Yes. You can export file lists for BatchPreprocessing, import PixInsight's SubframeSelector measurements, compare quality scores, and export selected frames to specific folders for processing.

AstroIndexer is compatible with any software that writes standard FITS headers. Tested with N.I.N.A, SGPro, APT, Voyager, Seestar S50, ASIair, Siril, and PixInsight. CSV export lets you use data in Excel, Google Sheets, or any analysis tool.

Yes. AstroIndexer offers a 30-day free trial with full access to all features. No account or credit card required. Just download and start using it.

The application enters read-only mode. You can still view and export your existing data, but new imports and analysis are disabled. All your data remains intact — nothing is deleted. Purchase a license to restore full access.

All licenses are one-time purchases with lifetime updates included. No subscription, no recurring fees.

1. Check that your license is valid (or you're within the trial period)
2. Run as Administrator (Windows) or check Security settings (macOS)
3. Check if antivirus software is blocking the application
4. Delete config.json in the data directory to reset settings
5. Reinstall if the issue persists

• Go to Tools → Maintenance → Optimize to compact the database
• Reduce thumbnail size in preferences
• Limit gallery to 4–6 columns
• Close unused tabs
• Ensure adequate free disk space

• Reduce "Max stars to analyze" in QA settings (500–1000 is usually sufficient)
• Process in smaller batches
• Close other resource-intensive applications
• AstroIndexer uses adaptive thread pooling — more CPU cores = faster analysis

1. Note the exact steps to reproduce the issue
2. Include any error messages shown
3. Attach the log file from logs/astroindexer.log in your data directory
4. Email support@astroindexer.com