What if Sirius and Canopus swapped places?


The transparency of the air is also of the greatest importance when observing the starry sky. The air is almost never the same warm everywhere, therefore not equally dense and the difference in density in neighboring air layers, the "streaks", cause a deflection of the light that comes from the stars and at the same time a decomposition into its colors, and thus the Appearance that is called the twinkling, the "scintillation" of the stars. Three things have to be kept apart: the change of location, the apparent restlessness of the stars, which occasionally can even increase to the point of jumping, the change in brightness and the change in color. Rising warm air currents make the otherwise invisible air visible through the resulting streaks. You can easily observe that over a sunlit roof, over a field. The streaks are moved by the wind and the light beam coming from the star must alternately penetrate thicker and thinner layers of air. Wind always blows, if not on the ground, then at a great height. At an altitude of 10,000 to 150,000 m we always have a wind that blows from the west. The scintillation is always stronger on the horizon than further up. From a height of 30 to 40 degrees, the change in brightness is simultaneous for all colors, so that the colored scintillation comes to an end at this height.

The dull glow there

The individual is from Cassiopeia,

And there is Jupiter.

Schiller, Wallenstein's death.

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Special hint

This chapter is part of the Springer Book Archives digitization project with publications that have appeared since the publisher's inception in 1842. With this archive, the publisher provides sources for both historical and disciplinary research, each of which must be viewed in a historical context. This chapter is from a book that was published before 1945 and is therefore not advertised by the publisher in its political-ideological orientation typical of the time.

Copyright information

© Verlag Von J. F. Bergmann 1924

Authors and Affiliations

  1. 1.A. D. University of WürƶburgGermany