About
What is NightSeam?
A deep-sky night-planning app. The web version runs entirely in your browser; the Windows desktop version adds the full Image Catalog for organizing your FITS captures.
12,116catalog objects
197curated showpieces
0servers involved
100%works offline
How it works
All calculations run on your device using standard astronomy algorithms — no internet service is involved. Sun, moon and twilight times follow the classic Meeus formulas, and object positions are accurate to well under a tenth of a degree.
Data, privacy & credits
- Catalog: Messier + OpenNGC (CC BY-SA 4.0).
- Images: Wikimedia Commons, each image under its own license.
- Weather: Open-Meteo, loaded on demand; weather data © Open-Meteo.com.
- Your data: stays on your device — in the browser's local storage or in a
datafolder next to the desktop app. Nothing is uploaded. See the privacy policy. - License: the software is free and open source (MIT license); the catalog data is CC BY-SA 4.0.