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Published byVerity Allen Modified over 8 years ago
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A (partially) refurbished John Wall 6” Classical Cassegrain Simon Dawes
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William James Observatorywww.itslifejim.btinternet.co.uk
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William James Observatorywww.itslifejim.btinternet.co.uk Assessment A light Breeze wobbles ‘scope Tripod to tall RA slow motion erratic Too heavy (16kg + tripod) OTA not balanced No clock drive Mirrors need re-aluminiumising Secondary mirror cover stiff Allan key needed to change eyepieces Focus completely lost with each eyepiece change Eyepiece is a long way out the back of the ‘scope Inconvenient to view objects
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William James Observatorywww.itslifejim.btinternet.co.uk Assessment A light Breeze wobbles ‘scope Tripod to tall RA slow motion erratic Too heavy (16kg + tripod) OTA not balanced No clock drive Mirrors need re-aluminiumising Secondary mirror cover stiff Allan key needed to change eyepieces Focus completely lost with each eyepiece change Eyepiece is a long way out the back of the ‘scope Inconvenient to view objects } Mount, Wedge, Tripod
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William James Observatorywww.itslifejim.btinternet.co.uk Counter weight doesn’t balance scope fully Slow motion causes huge back lash, so not ‘drivable’ Single unit makes this very top heavy, making mount prone to vibration in a breeze William Standing on Stool! Scope too tall adding to leaver effect
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William James Observatorywww.itslifejim.btinternet.co.uk Wedge added to allow GE Mount
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William James Observatorywww.itslifejim.btinternet.co.uk
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William James Observatorywww.itslifejim.btinternet.co.uk Assessment A light Breeze wobbles ‘scope Tripod to tall RA slow motion erratic Too heavy (16kg + tripod) OTA not balanced No clock drive Mirrors need re-aluminiumising Secondary mirror cover stiff Allan key needed to change eyepieces Focus completely lost with each eyepiece change Eyepiece is a long way out the back of the ‘scope Inconvenient to view objects
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William James Observatorywww.itslifejim.btinternet.co.uk Allan key needed to change eyepieces From micro densitometer The idea is that the leaver aids quick eyepiece changing. Eyepieces are permanently mounted in their own tubes HOWEVER Only have 1 tube! Eyepieces too large to store Unable to use eyepieces with other telescopes Completely loose focus with each change
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William James Observatorywww.itslifejim.btinternet.co.uk Assessment A light Breeze wobbles ‘scope Tripod to tall RA slow motion erratic Too heavy (16kg + tripod) OTA not balanced No clock drive Mirrors need re-aluminiumising Secondary mirror cover stiff Allan key needed to change eyepieces Focus completely lost with each eyepiece change Eyepiece is a long way out the back of the ‘scope Inconvenient to view objects Correcting prism fixes both of these
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William James Observatorywww.itslifejim.btinternet.co.uk Still to do A light Breeze wobbles ‘scope Tripod to tall RA slow motion erratic Too heavy (16kg + tripod) OTA not balanced No clock drive Mirrors need re-aluminiumising Secondary mirror cover stiff Allan key needed to change eyepieces Focus completely lost with each eyepiece change Eyepiece is a long way out the back of the ‘scope Inconvenient to view objects
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