About Above

Above shows the real sky over the place you stand, at the moment you look, and helps you find your way around it. It is free, with no accounts and no adverts.

How it works out the sky

Nothing on the screen is a picture of the sky. Each time a page opens, your own device works it out: the time where you are, how far the Earth has turned against the stars, and from that, where every star, the planets, the Sun and the Moon stand above your horizon.

The stars come from a catalogue of measured positions, brightness and colour: 8,920 of them, down to the faintest you can see from a dark site. The Sun, the Moon and the planets come from the formulas observatories publish. Checked against a professional ephemeris for 2026 to 2028, they land within a sixth of the Moon’s width of where they really are, and rising and setting times within fifteen seconds.

The colour of the sky, the twilight and the way faint stars drown in it follow the Sun’s true height below your horizon. Two things are drawn rather than measured: the hills along the bottom edge, which stand at the true compass points but are not your real skyline, and the fine texture inside the Milky Way, whose outline is measured.

The calendar was worked out the same way and then checked line by line against the published tables of the US Naval Observatory, NASA and the International Meteor Organization.

Your location stays with you

If you let Above use your location, your browser gives the position to this page, and the page works out the sky from it on your device. It is never sent anywhere. The site is a set of plain files; nothing on the other end asks for your position, and there are no accounts, no analytics and no cookies.

To remember your place and night mode for next time, the page keeps them in your browser’s own storage, with the position rounded to about a hundred metres. The name shown beside it, such as “Near Lisbon”, is the closest city in a list that comes with the site, found on your device too. Clearing this site’s data in your browser removes all of it.

Out under the sky

Red night mode turns every pixel red, the sky included, so your eyes stay used to the dark. It is the circle at the top of every page, or the N key.

Once you have opened Above, it keeps a copy of itself on your device, so it still works in a field with no signal. You can add it to your home screen and open it like an app.

Data sources and licences

Everything Above shows rests on the work of the people and institutions below. The full licence texts that must travel with the files are in licenses.txt.

Stars

The HYG database, version 4.1, by David Nash (astronexus.com), licensed under CC BY-SA 4.0. HYG brings together the Hipparcos, Yale Bright Star and Gliese catalogues.

Above keeps the 8,920 stars of magnitude 6.5 and brighter, with their positions, brightness, colour, constellation, proper names and Greek letters. The positions are turned into degrees and rounded, and a star with no measured colour is given a colour like the Sun’s. This trimmed copy, data/stars.json, is shared under the same licence, CC BY-SA 4.0.

Constellations

The Milky Way

The outline is the Milky Way Outline Catalog by Jose R. Vieira, as distributed with d3-celestial (BSD 3-Clause). Above fills its five brightness steps, softens their edges and draws a texture inside; the shape and place of the band are the catalogue’s.

Cities

GeoNames, licensed under CC BY 4.0. From its list of places with more than 15,000 people, Above keeps the 1,100 capitals and cities of more than 600,000, with their positions and time zones. Greenwich, the starting place, is added by hand at the Royal Observatory.

Sun, Moon and planets

The Sun and the Moon follow Jean Meeus, Astronomical Algorithms (second edition, 1998). The planets follow the Keplerian elements of E. M. Standish, Jet Propulsion Laboratory, for 1800 to 2050. The difference between the Earth’s clock and atomic time follows the polynomials of Fred Espenak and Jean Meeus for NASA, and the turning of the sky the IAU’s 1976 and 1982 conventions.

On the solar system page, sizes come from NASA’s planetary fact sheets, the directions of the poles from the IAU Working Group on Cartographic Coordinates and Rotational Elements, and the edges of Saturn’s rings from NASA’s Saturnian rings fact sheet.

Calendar

Moon phases, seasons, oppositions, conjunctions and eclipses for 2026 and 2027 were computed with Astronomy Engine by Don Cross (MIT licence) and checked against the US Naval Observatory’s Astronomical Applications tables and NASA’s eclipse lists. Eclipse predictions by Fred Espenak, NASA’s GSFC; where each solar eclipse can be seen is described in NASA’s words.

Meteor shower rates, radiants, dates of activity and the solar longitude of each peak are from the International Meteor Organization’s Meteor Shower Calendars for 2026 and 2027 by Jürgen Rendtel.

Clusters, nebulae and galaxies

Positions, kinds, sizes and constellations from OpenNGC by Mattia Verga, release v20260501, licensed under CC BY-SA 4.0.

The distances and brightness of the 110 Messier objects come from the table in Wikipedia’s article Messier object, after the SEDS Messier catalogue; for the other 27 objects, from the Wikipedia article on each one, which names the measurement it uses, and for the Jewel Box’s brightness, from the SEDS NGC pages. Wikipedia’s text is licensed under CC BY-SA 4.0. Above’s list of 137 objects, data/dso.json, is shared under the same licence.

Object pages

The facts about each star come from the HYG database above: its distance from the parallax the Hipparcos satellite measured, its kind from its spectral type, and the light it gives out. Deneb is too far for a sure parallax, so its page gives the distance from Schiller and Przybilla (2008), about 2,600 light years, and says how far the estimates spread. The sizes, distances, days, years, temperatures and moons of the Sun, the Moon and the planets come from NASA’s planetary fact sheets (NSSDCA, Goddard Space Flight Center), which are in the public domain. The one-sentence summaries are Above’s own. data/objects.json is shared under CC BY-SA 4.0.

When each object rises, stands highest and sets is worked out on your device for your place, in the same way as the rest of the sky.

Type and code

Mona Sans by the Mona Sans Project Authors at GitHub, under the SIL Open Font License 1.1, served from this site. Smooth scrolling by Lenis from darkroom.engineering, MIT licence. Everything else, the sky included, is drawn by Above’s own code.