The best of the bad seeing (Giuseppe Donatiello)

The best of the bad seeing

This is also astronomy. In astronomy it is indicated as "seeing" the whole set of phenomena that contributes to the deterioration of the quality of the telescopic images, introduced mainly by the lower and dense layers of the atmosphere. The gaseous mass of the atmosphere is, in fact, generally animated by convective thermal movements in a vertical direction, or by laminar flow activated by barometric differences. In any case, the movements of the air easily give rise to turbulence, viscosity, fragmentation and recomposition of gaseous bodies (cells) of very different entities; in other words, that chaotic and unpredictable movement, the index of refraction of the air, is responsible for the deterioration of the telescopic images of the celestial sources.

This deterioration is a function of the wavelength and causes, therefore, variations in color of the observed astronomical source, as well as variations in the brightness and in the apparent position.

In this very instructive image, some of the most unusual deformations in the diffraction figure have been collected.

To get them, I extracted single frames from short videos to stop the weirdest figures. Due to the atmospheric agitation, the star figures slightly out of focus are in continuous random movement. When the atmosphere is calm, the figures are quite regular as in the first and last figure of the series. When the figures are regular, astronomers define this situation as "favorable seeing" and the observations are very fruitful.

With all the evidence, the "best" of the worst seeing was included in this collection. However, these shapes also have their charm.

The images were obtained in the course of instrumental test with the same camera

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