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Kern Arc
The Kern arc is an extremely rare atmospheric optical phenomenon belonging to the family of ice crystal halos. It is a complete and faint circle around the zenith, in contrast to the related and much more common circumzenithal arc, which is only ever a partial circle. The Kern arc is named after H.F.A. Kern in the Netherlands, who first reported it on October 8, 1895.S. W. Visser: ''Optische verschijnselen aan de hemel'', bladzijde 58, § 44: ''De gespiegelde circumzenitale boog. Boog van Kern'' Since then it has been reported on six occasions. (Mikkilä's description of the observation.) It is formed by rays entering the top faces of horizontal plate crystals and leaving through a near vertical side face. Kern arc rays undergo an internal reflection off a side face inclined at 60° to the exit face. Near ''triangular'' hexagonal crystals with three alternate side faces much shorter than the others allow the Kern arc to occur. The first photographs of the Kern arc were taken by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Phenomenon
Optical phenomena are any observable events that result from the interaction of light and matter. All optical phenomena coincide with quantum phenomena. Common optical phenomena are often due to the interaction of light from the Sun or Moon with the atmosphere, clouds, water, dust, and other particulates. One common example is the rainbow, when light from the Sun is reflected and refracted by water droplets. Some phenomena, such as the green ray, are so rare they are sometimes thought to be mythical. Others, such as Fata Morganas, are commonplace in favored locations. Other phenomena are simply interesting aspects of optics, or optical effects. For instance, the colors generated by a prism are often shown in classrooms. Scope ''Optical phenomena encompass a broad range of events, including those caused by atmospheric optical properties, other natural occurrences, man-made effects, and interactions involving human vision (entoptic phenomena)''. Also listed here are unexplain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halo (optical Phenomenon)
A halo () is an optical phenomenon produced by light (typically from the Sun or Moon) interacting with ice crystals suspended in Earth's atmosphere, the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Many of these appear near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky. Among the best known halo types are the circular halo (properly called the 22° halo), light pillars, and sun dogs, but many others occur; some are fairly common while others are extremely rare. The ice crystals responsible for halos are typically suspended in cirrus cloud, cirrus or cirrostratus clouds in the upper troposphere (), but in cold weather they can also float near the ground, in which case they are referred to as diamond dust. The particular shape and orientation of the crystals are responsible for the type of halo observed. Light is reflection (physics), reflected and refraction, refracted by the ice cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumzenithal Arc
The circumzenithal arc, also called the circumzenith arc (CZA), the upside-down rainbow, and the Bravais arc,"Mémoire sur les halos et les phénomènes optiques qui les accompagnent", J. de l' École Royale Polytechnique 31(18), 1-270, A. Bravais, 1847 is an optical phenomenon similar in appearance to a rainbow, but belonging to the family of halos arising from refraction of sunlight through ice crystals, generally in cirrus or cirrostratus clouds, rather than from raindrops. The arc is located a considerable distance (approximately 46°) above the observed Sun and at most forms a quarter of a circle centered on the zenith. It has been called "a smile in the sky", its first impression being that of an upside-down rainbow. The CZA is one of the brightest and most colorful members of the halo family. Its colors, ranging from violet on top to red at the bottom, are purer than those of a rainbow because there is much less overlap in their formation. The intensity distribution a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Netherlands. The Netherlands consists of Provinces of the Netherlands, twelve provinces; it borders Germany to the east and Belgium to the south, with a North Sea coastline to the north and west. It shares Maritime boundary, maritime borders with the United Kingdom, Germany, and Belgium. The official language is Dutch language, Dutch, with West Frisian language, West Frisian as a secondary official language in the province of Friesland. Dutch, English_language, English, and Papiamento are official in the Caribbean Netherlands, Caribbean territories. The people who are from the Netherlands is often referred to as Dutch people, Dutch Ethnicity, Ethnicity group, not to be confused by the language. ''Netherlands'' literally means "lower countries" i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sotkamo
Sotkamo is a municipality of Finland, located in the Kainuu region about east of Kajaani, the capital of Kainuu. Vuokatti, in west of Sotkamo, is the most populous village in the municipality and also a popular skiing resort. Both Hiidenportti National Park and Tiilikkajärvi National Park are located in the municipality. The municipality has a population of () and covers an area of of which is water. The population density is . In sports, Sotkamo is known for its pesäpallo team, Sotkamon Jymy. The Hiukka Stadium is the home field of Sotkamon Jymy, and its well-known competitor is Vimpelin Veto from Vimpeli, known as long-time arch-enemy of Sotkamon Jymy. One of the major landmarks of Sotkamo is the sandy beach of Hiukka, which locates by the lake Iso Sapsojärvi, just beside the Sotkamo center. In Vuokatti ski center you can find the lake Nuasjärvi and the Vuokatti Hill. History Sotkamo has grown beside a water route formed by a continuous band of lakes and rivers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finland
Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, opposite Estonia. Finland has a population of 5.6 million. Its capital and largest city is Helsinki. The majority of the population are Finns, ethnic Finns. The official languages are Finnish language, Finnish and Swedish language, Swedish; 84.1 percent of the population speak the first as their mother tongue and 5.1 percent the latter. Finland's climate varies from humid continental climate, humid continental in the south to boreal climate, boreal in the north. The land cover is predominantly boreal forest biome, with List of lakes of Finland, more than 180,000 recorded lakes. Finland was first settled around 9000 BC after the Last Glacial Period, last Ice Age. During the Stone Age, various cultures emerged, distinguished by differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowgun
Snowmaking is the production of snow by forcing water and pressurized air through a "snow gun", also known as a "snow cannon". Snowmaking is mainly used at ski resorts to supplement natural snow. This allows ski resorts to improve the reliability of their snow cover and to extend their ski seasons from late autumn to early spring. Indoor ski slopes use snowmaking. They can generally do so year-round as they have climate-controlled environments. The use of snowmaking machines has become more common as changing weather patterns and the popularity of indoor ski resorts create a demand for snow beyond that which is provided by nature. Snowmaking machines have addressed the shortage in the supply of snow; however, there are significant environmental costs associated with the artificial production of snow. According to the European Environment Agency, the length of snow seasons in the northern hemisphere has decreased by five days each decade since the 1970s, thus increasing the deman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursa (Finland)
Ursa Astronomical Association () is the largest Astronomy, astronomical association in Finland. Ursa was founded on 2 November 1921. Founding members include a renowned Finnish astronomer Yrjö Väisälä. In 1926 Ursa established the Ursa Observatory in Kaivopuisto district of Helsinki. In 2007 the Tähtikallio Observatory & Education Center was established in Artjärvi, its current equipment includes an Astrofox 36" Folded Newtonian Open tube telescope, an Alluna 16" Ritchey-Chrétien telescope, a Meade Instruments, Meade 16" Meade LX200, LX200GPS Schmidt-Cassegrain telescope, a Sky-Watcher ED 120mm Refracting telescope, refractor telescope fitted with a Baader AstroSolar Astronomical filter#Solar filters, Solar Filter and a piggybacked Coronado SolarMax 40 H-Alpha telescope. Ursa's primary functions include advancing amateur astronomy and astronomical education. They have published a magazine ''Tähdet ja avaruus'' since 1971 and have provided awards to exceptional members of am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halo (optical Phenomenon)
A halo () is an optical phenomenon produced by light (typically from the Sun or Moon) interacting with ice crystals suspended in Earth's atmosphere, the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Many of these appear near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky. Among the best known halo types are the circular halo (properly called the 22° halo), light pillars, and sun dogs, but many others occur; some are fairly common while others are extremely rare. The ice crystals responsible for halos are typically suspended in cirrus cloud, cirrus or cirrostratus clouds in the upper troposphere (), but in cold weather they can also float near the ground, in which case they are referred to as diamond dust. The particular shape and orientation of the crystals are responsible for the type of halo observed. Light is reflection (physics), reflected and refraction, refracted by the ice cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumzenithal Arc
The circumzenithal arc, also called the circumzenith arc (CZA), the upside-down rainbow, and the Bravais arc,"Mémoire sur les halos et les phénomènes optiques qui les accompagnent", J. de l' École Royale Polytechnique 31(18), 1-270, A. Bravais, 1847 is an optical phenomenon similar in appearance to a rainbow, but belonging to the family of halos arising from refraction of sunlight through ice crystals, generally in cirrus or cirrostratus clouds, rather than from raindrops. The arc is located a considerable distance (approximately 46°) above the observed Sun and at most forms a quarter of a circle centered on the zenith. It has been called "a smile in the sky", its first impression being that of an upside-down rainbow. The CZA is one of the brightest and most colorful members of the halo family. Its colors, ranging from violet on top to red at the bottom, are purer than those of a rainbow because there is much less overlap in their formation. The intensity distribution a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
