The things that are important is that the encoder takeoff pulley or gear be accurately centered on the shaft of the DOB centerline otherwise the belt will be tight at one point and loose at 180 degrees and the position won`t be that accurate. As far as the encoder itself, it can have a different axis by a little bit just so long as when you look at it, there is not differential of motion as you move the scope around. Do some experiments on paper or in your head as to what an extreme of what you are thinking of is going to do provided the motion of the scope is properly moved to the encoder. An offset wheel will make the motion uneven and thus bad.
The other thing that you have to remember is that the encoders don`t like a lot of stress on them as they will quickly wear the bearings out and then you will be buying new encoders when that happens. Let the encoders kind of float a bit so that they can find thier own exact postion that they find to be happy. When you make the connection to the scope, also use a low stress method for the same reason. The belts (if that`s what you are using) don`t need to be tight as the friction of the encoder is quite small. Snugging the belt up will be quite sufficient.

• Dob plans: Mirror Cell. - bzrd/">bzrd - November 29, 1999 - 00:01 UTC
  • RE: Dob plans: Mirror Cell. - bobmay - August 22, 2000 - 17:05 UTC