<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">Cassegrain telescopes</topic></authority><related type="broader"><topic>reflecting telescopes</topic></related><variant type="other"><topic>Cassegrain telescope</topic></variant><variant type="other"><topic>telescopes, Cassegrain</topic></variant> <note xml:lang="en"><![CDATA[ Modified Gregorian telescopes that contain Cassegrain reflectors, designed to reflect and focus light toward their primary light-gathering mirrors. Designed in 1672 by French priest Laurent Cassegrain, the improvement was rediscovered in the late 18th century as it was proven to reduce spherical aberration. ]]></note></mads>