Platform Drive And Telescope Bearings As Requested
Fig 1 The Motor drive to the platform uses ¼ inch whitworth threaded shaft and half nut to transfer the required energy to move the equatorial platform on which the telescope is mounted Fig 2. Owing to belt slip in cold weather I rebuilt the original drive using a 12 pitch worm and worm wheel to drive the threaded shaft. This and the Dick Smith pulse drive controller has proved most satisfactory. One very important modification is the ball joint that connects the half nut to the slotted yoke attached to the top board of the platform. This arrangement provides a smooth friction free drive, which the pin in a simple yoke did not provide. The ball fitting is available at bearing supply stores. The yoke is fabricated with a number of aluminium sections and lubricated to provide the ball attachment with a smooth sliding action. Another modification worth mentioning is rubber dampening to the attachment of the motor drive to the platform base. This dampens out any vibration, which can reflect in the final captured image.
Disappointed with Teflon slides and after numerous methods to over come stiction to the initial movement, both in the elevation and rotation of the scope, I installed bearings and now have a 99% perfect system. Figs 3 and 4 three-part construction of the ball rollers running on Formica glued to the scope’s base. Three of these bearings provide a smooth turning motion whereas the elevation bearings Fig 9 (4 of) are 20 mm dia sealed ball races with metal faced side bearings. These have made elevation movement really smooth, but it requires more precise balance weights to accommodate the change in the angle of elevation. No hardship to change weights for what one receives in a smooth movement.
Figs 5 and 6 show the locking down of the platform for transport and storage. Just a few minutes to return the platform to centre and raise the four supports into the slotted plates that position them while lifting the upper section off the main platform equatorial bearings. The four metal threads are screwed down to finally lock the platform.
Fig 7 The Dick Smith pulse control kit encased. Fig 8 Remote focus control.
Please feel free to ask questions if I haven't provided sufficient information. I'd like to receive your comments. this includes the Remote Focus submission.
