About NowSky
NowSky is an interactive sky and solar-system simulator that recreates tonight's sky from your location and the motion of the solar system with real orbital calculations. Find constellations, planets, satellites and eclipses in the sky above you, and run probes and comets along their orbits through time. Alongside that, it puts everything from a proton (10⁻¹⁵ m) to the observable universe (10²⁷ m) on one ruler for size and speed comparisons.
Why it exists
There is plenty of astronomy content, but few tools show "how big Jupiter is" and "where Jupiter is right now" in one place, with an honest sense of proportion. Textbook diagrams exaggerate scale, and professional planetarium software has a steep learning curve. NowSky aims for the middle: numerically grounded, but instantly usable in a browser with your fingers. It is a reference and learning aid — for precision work such as observation planning, please cross-check professional sources.
Data sources
- Planet & moon orbits — mean orbital elements (J2000) with Kepler-equation solutions. Moon and Sun positions use abridged series from Meeus' Astronomical Algorithms (60 longitude/distance and 60 latitude terms for the Moon).
- Star catalog — bright stars and constellation figures are approximations (J2000) based on public catalogs such as HYG.
- Satellite orbits — public TLE data from Celestrak.
- Object photos & write-ups — public material from Wikimedia Commons/Wikipedia, shown with attribution.
- Event times — eclipse times are computed from our own new/full-moon solutions and match published values within a few minutes; pages note that they are approximate.
On accuracy
On-screen positions are approximations. Stars use J2000 places without precession or proper motion; planet positions come from mean elements and can be off by arcminutes. Magnification features intentionally break true scale. Each view's footer explains its specific approximations under "How it's computed".
Who writes the articles, and how
Every article, object page, guide and blog post is written by BrightK, who runs NowSky. BrightK drafts each text and its structure, AI tools help polish wording and layout, and BrightK checks every figure, date and source before publishing. Unconfirmed schedules are marked as planned, unknown figures are left out, and superlatives are avoided. The reference date and calculation method behind each figure are stated on the page.
Found a mistake? Tell us on the contact page — confirmed corrections update the page and its date, and every change is listed in the update log.
Who runs this
NowSky is an independent project built and run by BrightK, a single developer who writes the simulator, the articles and the fixes. Suggestions and bug reports are welcome on the contact page. Terms and the privacy policy are linked in the footer.