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Diffraction spike. Diffraction spikes are lines radiating from bright light sources, causing what is known as the starburst effect[1] or sunstars[2] in photographs and in vision. They are artifacts caused by light diffracting around the support vanes of the secondary mirror in reflecting telescopes, or edges of non-circular camera apertures ...
Hertzsprung–Russell diagram. An observational Hertzsprung–Russell diagram with 22,000 stars plotted from the Hipparcos Catalogue and 1,000 from the Gliese Catalogue of nearby stars. Stars tend to fall only into certain regions of the diagram. The most prominent is the diagonal, going from the upper-left (hot and bright) to the lower-right ...
The phrase "fixed star" is technically incorrect, but nonetheless it is used in an historical context, and in classical mechanics. When used as a visual reference for observations, they usually are called background stars or simply distant stars, still retaining the intuitive meaning of they being "fixed" in some practical sense.
Orion's Belt is an asterism in the constellation of Orion.Other names include the Belt of Orion, the Three Kings, and the Three Sisters. [1] The belt consists of three bright and easily identifiable collinear star systems – Alnitak, Alnilam, and Mintaka – nearly equally spaced in a line, spanning an angular size of ~ 140′ (2.3°).
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the rainbow of colors interspersed with spectral lines. Each line indicates a particular chemical element ...
Orion's two brightest stars, Rigel (β) and Betelgeuse (α), are both among the brightest stars in the night sky; both are supergiants and slightly variable. There are a further six stars brighter than magnitude 3.0, including three making the short straight line of the Orion's Belt asterism.
In astronomy, extinction is the absorption and scattering of electromagnetic radiation by dust and gas between an emitting astronomical object and the observer. Interstellar extinction was first documented as such in 1930 by Robert Julius Trumpler. [1][2] However, its effects had been noted in 1847 by Friedrich Georg Wilhelm von Struve, [3] and ...
In astronomy, a syzygy (/ ˈsɪzədʒi / SIZ-ə-jee; from Ancient Greek συζυγία (suzugía) 'union, yoke') [1] is a roughly straight-line configuration of three or more celestial bodies in a gravitational system. [2] The word is often used in reference to the Sun, Earth, and either the Moon or a planet, where the latter is in conjunction ...