About SunnyTracker: Methods, Sources & Contact
Who makes SunnyTracker, how sun, moon, twilight and eclipse times are calculated, how accurate they are, which data sources are used and how to reach us.
- SunnyTracker is an independent project by André Pfohl from Stutensee near Karlsruhe, Germany – a web app in ten languages and an Android app. Every figure on these pages is calculated for the exact coordinates of the place; nothing is looked up from other websites.
- Sunrise and sunset: NOAA's solar algorithms (after Jean Meeus). Sunrise and sunset are the moment the upper edge of the sun touches the horizon, with 0.833° for refraction and the sun's radius. Accurate to about a minute at mid latitudes; the height above sea level and mountains on the horizon are not taken into account.
- Twilight and photo hours: Civil twilight ends at 6°, nautical at 12°, astronomical at 18° below the horizon. The golden hour is the time with the sun between 4° below and 6° above the horizon, the blue hour between 6° and 4° below.
- Moon: Phases and the distance to Earth after Meeus, Astronomical Algorithms (ch. 47 and 49): phases to a few minutes, the distance to a few hundred kilometres. A full moon closer than 362,000 km counts as a supermoon.
- Eclipses: Solar eclipses from NASA's Besselian elements (Fred Espenak), with the local circumstances after the Explanatory Supplement to the Astronomical Almanac – contact times to seconds, coverage to a percent. Lunar eclipses from NASA's Five Millennium Catalog.
- Time zones and clock changes: The IANA time zone database built into every browser and phone, so clock changes are right for any year without a hand-kept table.
- Places and solar yield: Places and populations from GeoNames (CC BY 4.0), checked against official statistics. Solar yield from PVGIS, the photovoltaic tool of the European Commission's Joint Research Centre, with hourly satellite data.
Contact
- sunnytracker@lyonberg.de