Night Sky Tools is a small independent site. It answers practical questions about the sky, such as what the Moon looks like tonight, when it is full, how long the 2027 eclipse lasts in a given town and which planets are up, and it answers them for the place where you are.
How the figures are computed
Nothing here is copied from another website. Every date, time and angle is calculated by Astronomy Engine, an open-source library published under the MIT licence. Its positions for the Sun, the Moon and the planets agree with NASA’s reference ephemerides to about one arcminute.
The calculations run in two places. Pages that do not depend on you, such as the calendar of a month or the timetable of an eclipse in Luxor, are computed once when the site is built. Everything that depends on your position, such as moonrise, the planets tonight or the eclipse seen from your street, is computed in your browser.
How far to trust them
- Moon phases agree with published tables to within about one minute. We check them in automated tests.
- Rise and set times are correct to about a minute for a flat horizon at sea level. Your real horizon matters more than the calculation.
- Eclipse durations use the lunar radius adopted by the NASA eclipse canons. They match published values to within a second or two; tables that model every mountain on the Moon’s edge can differ by that much.
- Planet visibility depends on thresholds that we state on the page. A clear sky and an open horizon are assumed.
If a figure looks wrong, it probably is: write to us and we will check it.
What we do not do
We do not sell eclipse tours or telescopes, and no page asks you to create an account. The site is not affiliated with NASA or with any observatory. The background map of the eclipse pages comes from Natural Earth, which is in the public domain.
Updated November 11, 2026