<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31443977</termId><termName>Cassegrain telescopes</termName><termType>PT</termType><termNote><![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. ]]></termNote><termCreatedDate>2026-03-30 21:04:11</termCreatedDate><relation><relationType>UF</relationType><termId>31443978</termId><termName>Cassegrain telescope</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31443979</termId><termName>telescopes, Cassegrain</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31444016</termId><termName>reflecting telescopes</termName><termType>PT</termType></relation></term>  </Zthes>