" : No alternate axes will be created for any of the Frames in the supplied
" : Alternate axes will be created for a Frame only if its Ident attribute is
set to a single upper case alphabetical character (A-Z).
This attribute is used only if the Encoding attribute of the FitsChan is set to (or
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.