Dark Sky Meter Pro

Turn your iPhone into a sky brightness meter. Measure in SQM and Bortle scale, log readings, and see how your night sky compares—with cloud forecast and map.

Dark Sky Meter Pro turns your iPhone’s camera into a sky brightness meter. Point at the night sky to get scientific readings in SQM (magnitudes per square arcsecond) and Bortle scale, plus NELM (naked-eye limiting magnitude) and an estimate of visible stars—so you can track light pollution and compare sites.

Measure

One-tap measurement: cover the lens for a dark frame, then point at the sky. Results in seconds.

Device-specific calibration (zero point) for better accuracy; optional FOV setting (default 20° for SQM-style comparison). Readings include location and time for your records.

My Data Save measurements locally and, with Sign in with Apple, sync across your devices. Export to CSV for analysis or sharing. Review history with SQM, Bortle, NELM, and location.

Clouds Simple cloud forecast for your location so you can plan when to go out.

Map See your (and optionally others’) measurements on a map to compare sky quality by place.

Info

Sunrise, sunset, and darkness window; moon phase, moonrise, and moonset for your location.

Built for stargazers, astrophotographers, researchers, and anyone curious about light pollution and dark skies. No extra hardware—just your iPhone.