#### Description:

This attribute controls the generation of FITS-WCS alternate axis keywords by the astWrite method. It determines which of the Frames in the FrameSet supplied to astWrite are used to create a set of alternate axis descriptions. It may be set to one of the following values (case insensitive):

- `"` ALL`"` : A set of alternate axes will be created for each Frame in the supplied FrameSet, excluding the Base and Current Frames. This is the default.

- `"` NONE`"` : No alternate axes will be created for any of the Frames in the supplied FrameSet.

- `"` IDENT`"` : Alternate axes will be created for a Frame only if its Ident attribute is set to a single upper case alphabetical character (A-Z).

Type:

  String.

#### Applicability

##### FitsChan

All FitsChans have this attribute.

#### Notes:

- This attribute is used only if the Encoding attribute of the FitsChan is set to (or defaults to) `"` FITS-WCS`"` or `"` FITS-PC`"` .

- The Current Frame in the FrameSet is always used to create the primary axis descriptions in the output FITS header.

- The Base Frame in the FrameSet is never used to create a set of alternate axis descriptions.

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