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ICameraV3Offset Property

This is a proposed ICameraV3 property.

The camera's offset (OFFSET VALUE MODE) OR the index of the selected camera offset description in the Offsets array (OFFSETS INDEX MODE)

Namespace:  ASCOM.DeviceInterface
Assembly:  ASCOM.DeviceInterfaces (in ASCOM.DeviceInterfaces.dll) Version: 3c9121baba46811fe6e53a58a05935662261416d
Syntax
int Offset { get; set; }

Return Value

Type: Int32

OFFSET VALUE MODE: The current offset value.

OR

OFFSETS INDEX MODE: Index into the Offsets array for the current camera offset
Exceptions
ExceptionCondition
PropertyNotImplementedExceptionWhen neither OFFSETS INDEX mode nor OFFSET VALUE mode are supported.
NotConnectedExceptionWhen the information is not available. (Some drivers may require an active connection in order to retrieve necessary information from the camera.)
InvalidValueExceptionWhen the supplied value is not valid.
Remarks

This is an optional property and can throw a PropertyNotImplementedException if Offset is not supported by the camera.

The Offset property is used to adjust the offset setting of the camera and has two modes of operation:
  • OFFSET VALUE MODE - The Offset property is a direct numeric representation of the camera's offset.
  • OFFSETS INDEX MODE - The Offset property is the selected offset's index within the Offsets array of textual offset descriptions.

A driver can support none, one or both offset modes depending on the camera's capabilities. However, only one mode can be active at any one moment because both modes share the Offset property to return the offset value. Client applications can determine which mode is operational by reading the OffsetMin, OffsetMax and Offset properties. If a property can be read then its associated mode is active, if it throws a PropertyNotImplementedException then the mode is not active.

If a driver supports both modes the astronomer must be able to select the required mode through the driver Setup dialogue.

During driver initialisation the driver must set Offset to a valid value.

Please note that ReadoutMode may in some cases affect the offset of the camera; if so, the driver must be ensure that the two properties do not conflict if both are used.

This is only available in Camera Interface Version 2 and later.

See Also