APERTURE
The diameter of a telescope’s light-gathering main lens or mirror. The bigger the aperture, the brighter and more detailed the image.
ASTERISM
A pattern of stars within a constellation.
AVERTED VISION
A technique for observing faint objects through a telescope. It involves viewing slightly to the side of the object, allowing its light to fall on an area of the eye more sensitive to light.
BINARY STAR
A system of two stars that orbit a common centre of gravity. The brighter star is classified as the primary; the dimmer is the secondary.
CELESTIAL EQUATOR
A projection of Earth’s equator into space.
CELESTIAL SPHERE
The projection of the night sky on to an imaginary sphere around Earth. The astronomical coordinates of right ascension and declination are also mapped onto this…
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The Astronomer's Yearbook (Digital) - 1 Issue, Astronomer's Yearbook 2022