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 Please click on the “Calibration” button:

... and let's assume you have a properly wired, stepper-based filter wheel hooked to the Seletek. In this window we'll define the position, in motor steps, for all available slots.

The first field, where the mouse pointer lies in the image, is an entry box; you can type in any position and, pressing “Go To”, the motor will move to that position. If instead you press “Set pos”, the actual position will be set equal to the number just entered. The current position can be seen in the other box (with the number centered) just to the left and a bit lower; it will be updated as soon as “Go To” (gradually as the motor moves) or “Set pos” (instantly).

The four buttons to the left will move the motor, step by step ( “<” and “>” ) or 10 steps at a time ( “<<” and “>>” ).

Our goal here is to move the motor until filter “1” is centered in the optical window; I suggest then setting the position to “0” (enter “0” in the upper right field and pressing “Set pos”), and clicking “Copy pos to slot” for the filter “1” (first row). The check box for the first filter will be marked, and the button “Move to slot” will be enabled.

Once the position for the first filter has been set, lets move the motor until filter 2 is centered, then press “Copy pos to slot” for filter 2, same for filter 3, etc., until up to 8 positions have been defined:

The buttons “Move To slot” allow us to check the alignment, and the position for each filter can be fine tuned.


Unchecking any checkbox will disable that filter position and all higher filters (unchecking the checkbox for filter 5 will disable 5, 6, 7 and 8).

Once the calibration is done, we can close this window (click the upper right, “X” button) and the changes will be reflected on the main one, with the buttons for the defined filters enabled.

From now on, pressing any button 1 to 8 will move the filter wheel to the defined position – of course this will be mostly done from imaging programs using the ASCOM standard.

Please note!

Stepper motors do not offer any way to check if they are powered or hooked or not – operating the filter wheel control with the filter wheel not properly connected will not result in any warning, but the position shown will not be physically correct.

The last position will be saved between executions of the program – just make sure you do not operate the filter wheel by hand (if at all possible).

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