aerial telescope
... that the aerial telescope is a type of very long focal length refracting telescope built in the second half of the 17th century that did not use a tube?
... that the <b id="mwD90"><a href="./Aerial_telescope" id="mwD94" rel="mw:WikiLink" title="Aerial telescope">aerial telescope</a></b> is a type of very long focal length <a href="./Refracting_telescope" id="mwD98" rel="mw:WikiLink" title="Refracting telescope">refracting telescope</a> built in the second half of the 17th century that did not use a tube?