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Setting the fullstepsize The azimuth drive 1. Calculate the reduction of the azimuth drive 2. Calculate the fullstep size as follows: 360 degrees/reduction/'number of motorsteps per revolution' = stepsize in degrees. Example: reduction = 1: 1400, motor makes 200 steps per revolution. Fullstep size is: 360/1400/200 = 0.001285 degrees. Scope.exe wants it in arcseconds, so multiply by 3600 = 4.626 arcseconds. 3. Enter this stepsize in config.dat. This is only a raw calculation and probably not accurate enough, so it has to be finetuned. Proceed as follows: 4. Attach a laser to the rocker, point it to a wall and mark the spot where the laser hits the wall. Set this azimuth position to zero in scope.exe 5. Let the scope move 360 degrees in azimuth. The laser should arrive exactly at the mark, but most likely, it will not. Make the laser hit the mark by using the azimuth buttons on the handpad and look how many degrees scope.exe says it has moved to arrive at the mark. For our example, let's say 361.4 degrees. This means the stepsize calculated in 2 was too small. The new stepsize is: (361.4/360) * old stepsize. So in the example above, the new stepsize will be (361.4/360)* 4.626 = 4.64399 arcseconds. 6. Enter this new value in config.dat. 7. Repeat the procedure to check. Change the stepsize in scope.exe, untill the laser points exactly at the mark when scope.exe confirms that the scope moved 360 degrees. The altitude drive. 1. Calculate the fullstep size the same
way you did for the azimuth drive (see 2 above) and enter this value in
config.dat. 2. Attach a precision 'bubble level' to the back side of the mirrorbox (or to the tube) when it is in vertical position. 3. Move to the position in which the bubble level says it's exactly vertical and set that position to zero in scope.exe. 4. Let the scope move 90 degrees to the horizon. 5. If the end postion is not exactly horizontal according to the bubble level, make it horizontal by using the altitude buttons of the handpad and write down the number of degrees scope.exe says the scope has moved to arrive at the horizontal position. Now set this position to 0 in scope.exe and do the same procedure back to vertical. 6. Do this 20 times or so and then calculate the mean number of degrees of all values you wrote down. Lets say this calculated mean is 88.954 degrees. This means the stepsize calculated in 1 is too large. 7. The new value to be entered in config.dat is: (88.954/90) x stepsize calculated in 1. |