In1855Mr。CookeobtainedasilvermedalatthefirstParisExhibitionforasix-inchequatorialtelescope。[8]Thiswasthehighestprizeawarded。AfewyearslaterhewasinvitedtoOsbornebythelatePrinceAlbert，todiscusswithhisRoyalHighnesstheparticularsofanequatorialmountingwithaclockmovement，forwhichhesubsequentlyreceivedtheorder。Onitscompletionhesuperintendedtheerectionofthetelescope，andhadthehonourofdirectingittoseveralofthecelestialobjectsfortheQueenandthePrincessAlice，andansweredtheirmanyinterestingquestionsastothestarsandplanetswithinsight。
Mr。Cookewasputtohismettletowardsthecloseofhislife。A
contesthadlongprevailedamongtelescopemakersastowhoshouldturnoutthelargestrefractinginstrument。Thetwotelescopesoffifteeninchesaperture，preparedbyMerzandMahler，ofMunich，werethelargesttheninexistence。Theirsizewasthoughtquiteextraordinary。Butin1846，Mr。AlvanClark，ofCambridgeport，Massachusetts，U。S。，spenthisleisurehour’sinconstructingsmalltelescopes。[9]Hewasnotanoptician，noramathematician，butaportraitpainter。Hepossessed，however，enoughknowledgeofopticsandofmechanics，toenablehimtomakeandjudgeatelescope。Hespentsometenyearsingrindinglenses，andwasatlengthenabledtoproduceobjectivesequalinqualitytoanyevermade。
In1853，theRev。W。E。Dawes——oneofMr。Cooke’scustomers——
purchasedanobject-glassfromMr。Clark。Itwassosatisfactorythatheorderedseveralothers，andfinallyanentiretelescope。