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.
June Solstice 2026
The longest day of the year is approaching — plan your observation session now.
Learn More →Astronomy Tools & Science & Environment
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.
Coord Converter
Free latitude longitude converter: WGS84, GCJ02 (China Mars), BD09 (Baidu) coordinate systems — no upload, 100% in your browser.
Telescope FOV Calculator
Telescope FOV calculator: eyepiece field of view, magnification, exit pupil, and CCD sensor coverage — all in your browser.
Planetary Hour Calculator
Classical Chaldean planetary hours for any date and location — calculated in your browser.
AstroSky
Windows desktop app — turn FITS data into stunning images. GPU-accelerated, 100% offline.
Science & Environment
Molar Mass Calculator & Eco-Metrics
June Solstice 2026 — June 21
7d leftSunday, June 21, 2026
Longest day of the year in the Northern Hemisphere. Calculate your local sunrise, sunset, and solar noon for the solstice.
Generate your first card to start your collection!
Use the Share button on any tool page to create and collect artwork cards.
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.
Monthly Astronomy Digest
Get sunrise/sunset times, moon phases, and stargazing tips for 50 world cities — delivered to your inbox once a month.
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