Copernicus Sentinel vs Sundial Builder

The Sentinel App is a gateway to knowing the Copernicus Sentinel satellites. It lets users track the satellites in real-time, discover their key elements, read the latest news and learn more about their products. Users can, among other things, explore detailed 3D models of the satellites, see the last and next time they have been and will be over the user's location, move the satellites to the time of the last data transmission and smoothly move them back to their current location over the 3D globe. Notifications can also be set to be warned when the satellites are flying by. ESA is developing a series of next-generation Earth observation missions, on behalf of the joint ESA/European Commission initiative Copernicus (previously GMES - Global Monitoring for Environment and Security). The goal of the program is to replace current and older Earth observation missions, such as ERS and Envisat, which have reached or are close to reaching the end of their operational life span. This will ensure a continuity of data so that there are no gaps in ongoing studies. Each mission will focus on a different aspect of Earth observation, such as Atmospheric, Oceanic or Land monitoring, and the data will be of use in many applications.

HORIZONTAL SUNDIAL Built on a flat horizontal surface. - Hour lines converge toward true south in the northern hemisphere, or true north in the southern hemisphere. - The gnomon is fixed at the "center of the sundial," where the hour lines meet, is tilted relative to the horizontal plane by an angle equal to the absolute value of the local latitude, it must point to the celestial north pole (northern hemisphere) or celestial south pole (southern hemisphere). Required data: - Latitude between 5° and 80° (use negative values for southern hemisphere) - Longitude (used only to calculate correction between solar time and civil time) - Location can be entered manually or retrieved via the device's GPS - Gnomon length: between 10 cm and 30 cm. The final tilted length is calculated by the app - Equation of Time and longitude correction are shown on screen and in the CSV file --- VERTICAL SUNDIAL Built on a vertical wall facing any direction (south, west, east, north, or intermediate). - Hour lines start from the "center of the sundial" and extend downward - The gnomon is fixed at this center point - The gnomon is inclined based on latitude and wall orientation. It equals the latitude only when facing due south or due north - The gnomon must point to the celestial north pole (northern hemisphere) or celestial south pole (southern hemisphere) Required data: - Latitude between 5° and 80° (use negative values for southern hemisphere) - Longitude (used only for time correction) - Location can be entered manually or via GPS - Gnomon length: between 10 cm and 30 cm. The app computes the final inclined length - Wall orientation: - Northern hemisphere: from 270° (east) to 360°≡0° (south) to 90° (west) - Southern hemisphere: from 270° (east) to 180° (north) to 90° (west). --- GENERAL NOTES - The scale factor changes the sundial’s visual size but not the CSV values - Sundials near the edge of a time zone may show up to 30 minutes of difference between solar time and civil time - The app calculates the inclined gnomon length from the center - Alternatively, you can place a perpendicular gnomon from the origin point; in this case, only the tip’s shadow indicates the time - Wall orientation is measured clockwise from south: - 0° = South - 90° = West - 180° = North - 270° = East