Fraunhofer and his spectral lines

On the Suggested Mutual Repulsion of Fraunhofer Lines.

Fraunhofer Lidar Prototype in the Green Spectral Region for Atmospheric Boundary Layer Observations

A lidar detects atmospheric parameters by transmitting laser pulse to the atmosphere and receiving the backscattering signals from molecules and aerosol particles. Because of the small backscattering cross section, a lidar usually uses the high sensitive photomultiplier and avalanche photodiode as detector and uses photon counting technology for collection of weak backscatter signals. Photon Co...

Supermassive black holes and spectral emission lines

It is widely accepted that active galactic nuclei (AGN) are hosting a supermassive black hole in their center. The supermassive black hole is actively fueled by surrounding gas through an accretion disk, which produces a broad band continuum (from X-ray to radio emission). The hard photons from the accretion disk create the photoionized plasma around the central black hole, which emits a number...

Fraunhofer effect atomic absorption spectrometry.

The dark lines in the solar spectrum were discovered by Wollaston and cataloged by Fraunhofer in the early days of the 19th century. Some years later, Kirchhoff explained the appearance of the dark lines: the sun was acting as a continuum light source and metals in the ground state in its atmosphere were absorbing characteristic narrow regions of the spectrum. This discovery eventually spawned ...

Avicenna and his literary

Abu Ali Hossein Ebn Abdullah Ben Ali Ben Sinna entitled as Shayhk-o-Rayeis in the East and well known in the west by the name of Avicenna was born in a place called Afsharneh near the city of Bokhara in 980 AD but resided in the city of Balkh. He was five years old when his father took him to the city of Bokhara to study Holy Quran where his extraordinary memory became apparent and he memorized...