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ATLAS – (observing program) Australia Telescope Large Area Survey, a deep radio astronomical sky survey of two SWIRE fields covering a total of about 7 square degrees of sky. ATM – ( person ) hobbyist engaged in Amateur telescope making (may also refer to the book of the same title, Amateur Telescope Making )
The appearance of the Earth's sky at nighttime, when the Sun is below the horizon, and more specifically when clear weather and low levels of ambient light permit visibility of celestial objects such as stars, planets, and the Moon. The night sky remains a fundamental setting for both amateur and professional observational astronomy. non ...
But that same phenomenon can also sometimes make skies look red or orange. Here's a breakdown of how and why it all happens. But the science behind a blue sky isn't that easy.
Purple sky on the La Silla Observatory. [16] The sky can turn a multitude of colors such as red, orange, pink and yellow (especially near sunset or sunrise) and black at night. Scattering effects also partially polarize light from the sky, most pronounced at an angle 90° from the Sun.
The word is often used in reference to the Sun, Earth, and either the Moon or a planet, where the latter is in conjunction or opposition. Solar and lunar eclipses occur at times of syzygy, as do transits and occultations. The term is often applied when the Sun and Moon are in conjunction or in opposition . [4]
The color temperature can also change significantly with altitude, latitude, season, and weather conditions. Near the equinoxes in Chicago the sunsets occur in the middle of east-west streets (an event known as Chicagohenge), creating intriguing golden hour photography opportunities like this diffraction spike in an urban canyon .
The daily arc path of an object on the celestial sphere, including the possible part below the horizon, has a length proportional to the cosine of the declination.Thus, the speed of the diurnal motion of a celestial object equals this cosine times 15° per hour, 15 arcminutes per minute, or 15 arcseconds per second.
Walker's Law has been verified by observation [14] [10] to describe both the measurements of sky brightness at any given point or direction in the sky caused by a light source (such as a city), as well as to integrated measures such as the brightness of the "light dome" over a city, or the integrated brightness of the entire night sky. At very ...