Archive for the 'Instruments'

Achromatic Lens

Achromatic Lens – getting the colours under...
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Airy Disc

Airy Disc – limiting what you can see...
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Alidade

An alidade is a sighting device that is used to...
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Altazimuth Mount

A type of telescope mount, which allows the...
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Aperture

Aperture is the diameter of the main lens or...
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