Day sky
The daytime sky is mainly used astronomical, designation for the sky in days . The daytime sky lies between sunrise and sunset . The transition from the darkness of the night to the brightness of the day and vice versa is called twilight .
If the day sky is cloudless, you can see the blue scattered light of the sunlight. The blue hue is due to the wavelength dependence of Rayleigh scattering .
Even with relatively small telescopes , stars can be seen during the day - about the 50 brightest stars and almost always the inner planets Venus and Mercury . The former often even with the naked eye , if one knows their approximate position relative to the sun. At the turn of the century, such observations contributed greatly to the study of these planets and their suspected line structures. The first two outer planets Mars and Jupiter as well as bright artificial earth satellites can also be observed with precise forecasts. Also particularly bright comets like those that come into the inner solar system every few years.
Also, the Geodesy makes a clear daytime sky sometimes advantage, for example by measurement of Polaris azimuths for accurate orientation of surveying networks.
See also
Individual evidence
- ↑ H. Vogel: Gerthsen Physik , 18th ed., Page 553 10.3.5 Why is the sky blue? ; Springer-Verlag Berlin, ISBN 3-540-59278-4