Cosmoss – Night Sky Guide

Cosmoss turns your phone into a personal observatory.

Wherever you are, Cosmoss calculates exactly what's happening in your sky right now — no guessing, no generic star charts. Every reading is computed for your real location and the current moment.

TONIGHT, AT A GLANCE
See tonight's Moon phase, sunrise and sunset, and a Stargazing Score that factors in Moon brightness, twilight, and real cloud-cover forecasts — so you know at a glance whether it's a good night to look up, before you ever step outside.

FIND ANYTHING IN THE SKY
A real star field and constellation lines, rendered for your exact location and moment — not a generic chart. Guide Me points you straight at the Sun, Moon, or any planet using your phone's compass and motion sensors — just follow the on-screen guide until it's centered.

NEVER MISS A COSMIC EVENT
A full calendar of solar and lunar eclipses, meteor showers, planetary conjunctions and oppositions, full and new moons, equinoxes and solstices — with reminders so you don't miss the ones worth stepping outside for. Meteor showers include real peak dates, hourly rates, and radiant positions for the year's ten major showers, sourced from the International Meteor Organization.

EXPLORE THE SOLAR SYSTEM
Browse the Sun, all eight planets, the Moon, and the dwarf planets with real astronomical data, imagery, and side-by-side comparisons of size, distance, and orbit. Pick any two objects and compare them directly — see exactly how much bigger Jupiter is than Earth, or how far Saturn really is compared to Mars.

KEEP AN OBSERVATION JOURNAL
Log what you've seen — attach a photo, rate the seeing conditions, and build a personal record of every object you've spotted, organized and searchable over time.

TONIGHT, ON YOUR HOME SCREEN
Add the Cosmoss widget to see tonight's Stargazing Score, Moon phase, and best visible object at a glance — no need to open the app (iOS).

MADE FOR NIGHT VIEWING
A dedicated Night Vision mode dims and shifts the interface so you can check the app without losing your eyes' adjustment to the dark.

TAILORED TO WHAT YOU CARE ABOUT
Tell Cosmoss what interests you — stargazing, planets, meteor showers, eclipses, astrophotography, and more — and your Tonight dashboard and event recommendations adjust around it.

No account, no sign-up — Cosmoss works the moment you open it, and every sky calculation happens right on your phone, not on a server.

Available in English, French, Spanish, and Arabic, with full right-to-left support.

Cosmoss is ad-supported and free to use.