Your Browser-Based Science Lab
Your astronomy observation toolkit — see tonight's sky conditions, golden hour, moon phases, twilight, and more. No signup, no upload, works offline.
Official Microsoft Store app · 100% offline — your files never leave your PC
June Solstice 2026 — June 21
Astronomy Tools
Solar Insight Pro
Golden hour calculator, sunrise sunset time, sun position tracker, UV index, and laundry daylight forecast — all in your browser.
Twilight Calculator
Dusk and dawn calculator: find civil, nautical, and astronomical twilight times for any date and location — zero upload.
MoonSync
Moon phase calendar, lunar calendar, moonrise moonset calculator, and lunar surface illumination — all in your browser.
Sidereal Time Calculator
Local sidereal time calculator for telescope alignment — compute LST & GST from any UTC date and longitude — offline, no upload.
Telescope FOV Calculator
Telescope FOV calculator: eyepiece field of view, magnification, exit pupil, and CCD sensor coverage — all in your browser.
Events Calendar
Meteor showers, eclipses, conjunctions and oppositions — plan your next observing night by date.
Desktop astronomy software
AstroSky — turn FITS captures into stunning images
Free Windows desktop app with intelligent auto-stretch, 12+ scientific color maps, RGB channel compositing and 8K export. Runs 100% offline — process the night at home.
- Automatic FITS stretch
- 12+ scientific color maps
- 8K wallpaper export
- 100% offline processing
Learn More
Guides, articles, and deep dives into the science behind our tools.
Blog
In-depth articles on astronomy, chemistry, and our tools.
How to Plan Astrophotography Around Twilight
Find the true dark-sky window for deep-sky imaging.
How to Track Moon Phases for Observation Planning
Understand lunar illumination and its impact on stargazing.
How to Choose the Right Eyepiece for Your Telescope
Compute magnification, exit pupil, and true field of view.
Sunrise, Twilight & Moon Times in Major Cities
Pre-calculated solar, twilight, and lunar data for major world cities — updated daily.