first light (astronomy)
{{Short description|Term in astronomy for the first time a telescope is used to look at the Universe}}
{{about|the testing of telescopes|the first light of dawn|Twilight#Nautical twilight|the cosmogonical age|first light (cosmology)}}
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|Description =First light image from the Kepler space telescope{{cite web|last=Atkinson|first=Nancy|title=Kepler's "First Light" Images|date=16 April 2009|url=http://www.universetoday.com/29258/keplers-first-light-images/|publisher=Universe Today|access-date=2012-10-13}}
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In astronomy, first light is the first use of a telescope (or, in general, a new instrument) to take an astronomical image after it has been constructed. This is often not the first viewing using the telescope; optical tests will probably have been performed to adjust the components.
Characteristics
File:Hubble First Light, First Released Image (STScI-1990-04a).png's first light with its impaired WFPC, 1990]]
The first light image is normally of little scientific interest and is of poor quality, since the various telescope elements are yet to be adjusted for optimum efficiency. Despite this, a first light is always a moment of great excitement, both for the people who design and build the telescope and for the astronomical community, who may have anticipated the moment for many years while the telescope was under construction. A well-known and spectacular astronomical object is usually chosen as a subject.{{citation needed|date=July 2019}}
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