Changes

[https://de.wikipedia.org/wiki/Halde_Hoheward#Horizontobservatorium Horizon Observatory] (left) and horizontal [https://en.wikipedia.org/wiki/Sundial Sundial] with [https://en.wikipedia.org/wiki/Obelisk Obelisk] (right), [https://de.wikipedia.org/wiki/Halde_Hoheward Hoheward Spoil tip], [[Arts#IndustrialHeritageTrail:Category:Industrial Heritag Trail|The Industrial Heritage Trail]] <ref>360–degree [https://en.wikipedia.org/wiki/Panorama Panorama] Photo by [https://commons.wikimedia.org/wiki/User:Panofreak Panofreak], April 12, 2009, [https://de.wikipedia.org/wiki/Halde_Hoheward Hoheward Spoil tip] in [https://en.wikipedia.org/wiki/Herten Herten], [https://en.wikipedia.org/wiki/North_Rhine-Westphalia North Rhine-Westphalia], Germany, [[Arts#IndustrialHeritageTrail:Category:Industrial Heritag Trail|The Industrial Heritage Trail]] , view over the [https://en.wikipedia.org/wiki/Ruhr Ruhr area]. The observatory consists of a circular, flat surface of 88 m diameter, and a center forum lowered by 1.50 m with 35 m diameter with two arcs spanning [https://en.wikipedia.org/wiki/Meridian_%28astronomy%29 meridian] and [https://en.wikipedia.org/wiki/Celestial_equator celestial equator]. The horizon observatory is a modern version of [https://en.wikipedia.org/wiki/Prehistory prehistoric] [https://en.wikipedia.org/wiki/Stone_circle stone circles] and monuments such as [https://en.wikipedia.org/wiki/Stonehenge Stonehenge]. If the observer is located exactly in the lowered center, the plateau of the tip spreads in all directions like an artificial horizon, and with the help of bearing points the [https://en.wikipedia.org/wiki/Sunrise sunrise] and [https://en.wikipedia.org/wiki/Sunset sunset] at [https://en.wikipedia.org/wiki/Summer_solstice summer solstice], [https://en.wikipedia.org/wiki/Winter_solstice winter solstice] or [https://en.wikipedia.org/wiki/Equinox equinox] can be observed, by means of further bearing points also [https://en.wikipedia.org/wiki/Moon moon] solstices and the [https://en.wikipedia.org/wiki/Precession precession] of [https://en.wikipedia.org/wiki/Earth%27s_rotation Earth's axis] based on bearings of [https://en.wikipedia.org/wiki/Fixed_stars fixed stars]. The arcs divide the [https://en.wikipedia.org/wiki/Celestial_sphere celestial sphere] in eastern and western half as well as in [https://en.wikipedia.org/wiki/Northern_Hemisphere northern] and [https://en.wikipedia.org/wiki/Southern_Hemisphere southern hemisphere] and therefore serve as a [https://en.wikipedia.org/wiki/Solar_calendar solar calendar] at day, and at night, with the help of a [https://en.wikipedia.org/wiki/Luminous_paint self-luminous] scale as a guide of the [https://en.wikipedia.org/wiki/Night_sky night sky], [http://www.halden.ruhr/halden.html Halden im Ruhrgebiet] (German)</ref>