Nyx: Dark Sky Planner

About

Where should you go, and on which night, for the darkest sky? Nyx gives each night a darkness score from 0 to 100, from the Moon, the clouds, the sky glow and the hours of true darkness: for the 63 US national parks, for parks and dark-sky places around the world, and for any spot you save. It tells you what it doesn't know. Free. No account, no ads, no tracking. ONE SCORE, WITH ITS REASONS Four parts add up, and the weakest can cap the total, so a cloudy night never looks good. The line under the score names the cap. At the US national parks, closures from the National Park Service sit beside the number; elsewhere Nyx says plainly that it cannot check closures and links the park's own site. THE US NATIONAL PARKS All 63, checked by hand: named viewing spots, Bortle estimates, park alerts, ranger night-sky programs, campgrounds, step-free notes and access notes for parks reached by boat or plane. AROUND THE WORLD About 3,400 national parks and certified dark-sky places in 172 countries, from Wikidata, and starting points in about 31,500 towns and cities. Almost anywhere on land, sky brightness comes from NASA's satellite night lights and the usual clouds from ten years of weather records, both labeled as estimates. Save your own spot, a backyard or a pullout, and it is scored like a park. PLAN See tonight's darkest places within a straight-line radius, or browse the world by country and on a map. Each place has a month calendar with its best stretch of nights marked, and thirty nights on a timeline where the Moon changes shape as you scrub. Times are always local to the place. AN HONEST FORECAST For the next few days the cloud forecast counts in full. Further out it eases toward each place's usual clouds for the month, and beyond the forecast the usual clouds count alone, and say so. At the US national parks, three weather models are compared and heavy smoke can cap the score. WHAT'S UP TONIGHT Each night lists the Milky Way core, in either hemisphere, with its Moon-free hours; the planets; meteor showers with a rate range; and lunar eclipses the place can see. They never change the score. FIELD MODE On site, a red, dimmed screen for night-adapted eyes counts down to true darkness and each milestone of the night, and "Where to look" turns the real sky to wherever you point your iPhone. ON YOUR WRIST AND IN THE ROOM Apple Watch shows tonight's score, with complications that turn red at dusk. On Apple Vision Pro, stand under a US national park's computed sky. KEEP A LITTLE OF THE NIGHT Save places and get optional reminders for promising nights. Keep a private journal with notes and photos; each night becomes a star in your own constellation. Widgets show the best sky among your saved places. FOR MORE PEOPLE Nyx is designed for VoiceOver and the largest text sizes. Audio graphs let you hear a month of darkness, and a red mode keeps the whole app readable to night-adapted eyes. Nyx speaks English, Spanish, German, French and Japanese. PRIVATE AND OFFLINE Your location, journal and photos stay on your device. Three public services supply data, each with its own switch: park alerts from the National Park Service, and forecasts and smoke from Open-Meteo. Places abroad are asked for by whole regions, never one at a time, and a spot you save is sent only rounded to about 11 km. The Moon, the Milky Way, the calendar and your journal work offline. PLEASE NOTE Scores are planning estimates. They do not confirm clear skies or open roads. Check current conditions with the park before you travel. Weather data by Open-Meteo.com (CC BY 4.0). Smoke and usual clouds: Copernicus (CAMS, C3S). Night lights and Moon imagery: NASA. Places: Wikidata (CC0) and GeoNames (CC BY 4.0). Maps: Natural Earth. Meteor showers: IMO. Lunar eclipses: Fred Espenak, NASA's GSFC. Park data: National Park Service. Nyx is not affiliated with or endorsed by the National Park Service, NASA or DarkSky International.