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From a letter by Leonhard Euler some speculations on the height of auroas in the atmosphere can be derived.

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Based on visual noctilucent cloud data, the effect of the autumn transition of winds in the mesosphere is investigated. Following the autumnal transition of the mesospheric winds no noctilucent clouds were observed. The higher temperature of the winter mesosphere can be physically explain the fact that no noctilucent clouds occur during winter of the Northern Hemisphere. Accordingly, noctilucent clouds only occur on the typical summer mesosphere related to the low temperature there and due to the stable condition of the then mesospheric region.

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The development of the great aurora of January 18, 1770 has been discussed in a fundamental paper by Silberschlag (1770) and other authors. The aurora was observed in middle and low latitudes and in Northern latitude. In Central Europe it displayed all typical auroral forms, including the Corona.

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It is shown that during the Maunder Minimum auroras were observed frequently and the solar cycle was regular.

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A new interpretation of celestial phenomena became apparent after the appearance of the great aurora of March 1716. The philosopher Wolff presented a general lecture to the public in which he explained the aurora as a normal celestial phenomenon.

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A compilation of German auroral observation data for 1949-1964 is given. The observations are analysed with respect to the K p-index and seasonal variation. The appendix contains a full list of these observations.

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Sydney Chapman (1888–1970), the English geophysicist had close connections with German scientists both before and after World War II. The most important result of this co-operation is the monumental Chapman-Bartels monography on geomagnetism. The paper includes data on celebrations with Chapman and dedicated to Him.

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The data of increased airglow during the night June 30–July 1, 1908 as the Tunguska event has been noted, are analyized in detail. During the nights June 30–July 1, and July 2, 1908 noctilucent clouds has been observed. Furthermore some increased airglow has been noted.

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