DarkHours

Report scope
[■]Lunar[■]Weather[■]Targets & Milky Way[■]Space Weather Events[■]Meteor Showers[■]Clear Dark Hours[■]Sky & Horizon Glow[■]Satellites

Built for landscape astrophotography. Not for subscriptions.

Most of us only get a handful of clear, dark hours each month to do what we love. I built DarkHours because I needed a highly precise predictive tool for my own landscape astrophotography. It's open-source, free, and designed to help make the most of every dark hour.

Features

Target Windows

Every shootable target with its peak time and window, and why others are blocked due to clouds, moonwash, or light domes.

Milky Way Planner

A 360° view of the galactic plane over your horizon—altitude, bearing, and the best minute to shoot.

Sky & Horizon Glow

A horizon map of light domes around you. Know more than just the Bortle.

Nearby Dark Sky

Search for low bortle locations you can actually reach, with routing to facilities like parking, campgrounds, and viewpoints. All sorted by drive times.

Moonlight Modeling

Most tools treat the moon as binary: up means ruined. DarkHours models real scattered moonlight brightening at your target from live aerosol data. A crescent barely registers. A bright gibbous gets called out.

360° Sky Simulation

Drag around a rendered dome of tonight's actual sky: stars, Milky Way, moon phase, and light domes to scale. Scrub sunset to sunrise and watch visibility accurately change with conditions across the timeline

Aurora Forecast

NOAA space-weather data run through a geomagnetic visibility model for your exact location. Tiered honestly as overhead, naked eye, camera capture only, with the bearing to look toward.

Satellite Passes

ISS, Hubble, and Tiangong passes with rise, peak, and set times. Newly launched Starlink trains are tracked while they're still bunched and bright.

30 Day Best Night

A 30 day outlook. Compare conditions across multiple nights to identify the best windows.

Smoke & Haze Forecast

Wildfire smoke and upper-air aerosol data from ground sensors, and satellites.

Meteor Shower Predictions

Know when the next meteor shower will peak, the estimated meteors per hour, and visibility from your location.

Tailored Weather Forecasts

A two week, hour by hour forecast for: cloud cover, temperature, wind and humidity cloud layers, and wind - updated twice an hour. Plus three day atmospheric seeing, and transparency provided by 7Timer.
Plus the fundamentals:

Bortle class & SQM analysis, clear weather dark hours calculations, seeing & transparency forecasts, and cloud layers by altitude. Also a one-tap red night-vision mode for checking the forecast at 2 AM without losing your dark adaptation. Every metric sourced and time-stamped. Free, open-source, no account required.

View a sample report
Sedona, AZBortle 7 suburb — the dark-sky finder at workDeath Valley, CABortle 1 — pristine desert benchmarkCherry Springs, PABortle 2 — the East Coast classic