# Ephemeris

> Every day had its sky. Keep yours. Ephemeris turns a date and a place into a poster: the real weather and sky of that day, drawn by mathematics and given a name of its own. Printed in Europe.

Ephemeris (https://ephemerisart.com) is a studio that draws the real weather and sky of any day since 1940, anywhere on Earth, as a poster. The weather is ERA5 reanalysis from the Copernicus Climate Change Service, hourly; the sun's and moon's positions are computed. Each day is drawn as six figures and given a name coined from Latin and Greek roots. It is sold as digital files or as a printed poster. Made in France by Zakaria Hajji.

## Use it

- [Studio](https://ephemerisart.com/): choose a date and a place, see the six figures, buy the files or a poster
- [About, figures, prices and FAQ](https://ephemerisart.com/about)

## Products and prices (EUR, VAT included)

- Digital files: €9. The poster in every size as vector SVG and print-ready PDF, and the figure alone; sent by email a minute after payment. For your own prints, at home or at a print shop, as often as you like.
- Posters: A4 €35, 30 × 30 €42, A3 €45, 30 × 40 €49, A2 €69, 50 × 70 €79. Premium matte paper, 200 g/m², uncoated, printed in Europe, delivered in 4 to 7 working days, files included. Shipping €6.

## The six figures

- **I · Isotherm Relief**: The day's temperature as a mountain seen from above, read like a clock with noon at the top. Contour lines: the temperature hour by hour: the relief reaches further out at warmer hours; Hour ring: the 24 hours; the two small triangles mark the warmest and the coolest hour; Softened relief: humidity; Surface grain: cloud cover; Off-centre massif: pushed downwind by the day's mean wind; Small lakes: one for each hour of rain.
- **II · Wind Ledger**: The day's wind as a field of streamlines, from midnight on the left to midnight on the right. Direction of the lines: where the wind was blowing at each hour; Colour: the temperature through the day; Line weight: wind speed; Turbulence: how gusty and changeable the wind was; Short slanted strokes: rain, tilted by the wind.
- **III · Almanac Dial**: A 24-hour instrument face, noon at the top, read from the outside in. Arrows: wind direction and strength, north up; Light and dark sectors: night, the three twilights and daylight, from the sun's position; Spokes and curve: the temperature every 15 minutes, with the day's extremes; Rays: sunrise and sunset; Shaded ring: cloud cover, hour by hour; Inward bars: rainfall; Thin trace: air pressure; Centre: the moon, in its exact phase.
- **IV · Pulse Ridges**: Forty profiles, one every 36 minutes, from midnight at the top to midnight at the bottom. Height: temperature; Drift of the crest: the east–west wind; Roughness: humidity; Fine chatter: rain.
- **V · Pendulum**: A harmonograph, the Victorian drawing machine of swinging pendulums, tuned by the day. Shape of the loops: the pressure: a building high or a deepening low; Slow turning into bands: the mean wind; How long the pen swings: humidity; Size: cloud and warmth; Starting points: the moon's age and the times of sunrise and sunset; Colour: the temperature as the pen moves.
- **VI · Celestial Plate**: The sky above the place as if you were lying on your back: the zenith at the centre, north up, east on the left. Outer rings: the twilights, down to 18° below the horizon; Sun's path: computed every ten minutes; hourly marks coloured by temperature, larger when the sun shone; Moon: its path, and its disc at its highest, in its exact phase; Grid: height above the horizon every 15°, bearings every 30°.

## FAQ

### What is Ephemeris?
Ephemeris turns a date and a place into a poster: the real weather and sky of that day, drawn by mathematics and given a name of its own. Printed in Europe. It is a studio at https://ephemerisart.com: choose a date and a place, and see the day drawn as six figures.

### Where does the weather come from?
From ERA5, the reanalysis of the Copernicus Climate Change Service (ECMWF): hourly temperature, humidity, pressure, precipitation, cloud cover and wind for the model grid cell nearest the place (about 25 km). The sun's and moon's positions are computed by Ephemeris.

### Which dates and places can I choose?
Any date from 1 January 1940 to about a week ago, and any place on Earth, by name or by coordinates.

### What do I receive?
Either the digital files for €9: the poster in every size as vector SVG and print-ready PDF, plus the figure alone, by email a minute after payment. Or a poster from €35 to €79 (A4, 30 × 30, A3, 30 × 40, A2, 50 × 70), printed in Europe on premium matte paper, 200 g/m², uncoated, delivered in 4 to 7 working days, with its files included.

### Is every poster unique?
Every poster is computed from one day's real data. The same day, place, figure and palette always give exactly the same artwork; each carries an edition number and a fingerprint.

### How is the name of the day chosen?
A word coined for this day by AI, built from Latin and Greek roots that describe its weather and sky. It becomes the title of the poster. You can ask for another, or type your own title.

### Where do you ship?
To 20 countries, including France and the rest of the EU, the UK, Switzerland, Norway, the US and Canada. Shipping is €6 per poster.

### Can I return a poster?
Posters are made to order for a specific day, so they can't be returned for a change of mind; a damaged or faulty print is always replaced.

## Legal and contact

- Contact: studio@ephemerisart.com
- [Mentions légales](https://ephemerisart.com/legal/mentions-legales), [CGV](https://ephemerisart.com/legal/cgv), [Confidentialité](https://ephemerisart.com/legal/confidentialite)
- Share image: https://ephemerisart.com/og.png