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FilterWheelPosition Property

Sets or returns the current filter wheel position

Namespace:  ASCOM.DriverAccess
Assembly:  ASCOM.DriverAccess (in ASCOM.DriverAccess.dll) Version: 3c9121baba46811fe6e53a58a05935662261416d
public short Position { get; set; }

Property Value

Type: Int16


InvalidValueExceptionMust throw an InvalidValueException if an invalid position is set
NotConnectedExceptionMust throw an exception if the Filter Wheel is not connected
Write a position number between 0 and N-1, where N is the number of filter slots (see Names). Starts filter wheel rotation immediately when written. Reading the property gives current slot number (if wheel stationary) or -1 if wheel is moving.

Returning a position of -1 is mandatory while the filter wheel is in motion; valid slot numbers must not be reported back while the filter wheel is rotating past filter positions.


Some filter wheels are built into the camera (one driver, two interfaces). Some cameras may not actually rotate the wheel until the exposure is triggered. In this case, the written value is available immediately as the read value, and -1 is never produced.

See Also