"(for Right Ascension and Declination).
If a Symbol value has not been set for a Frame axis, then a suitable default is supplied.
", where n is 1, 2, etc. for successive axes, and Domain is the value of the Frame
’s Domain attribute (truncated if necessary so that the final string does not exceed 15 characters). If no Domain value has been set,
"is used as the Domain value in constructing this default string.
") as appropriate for the particular celestial coordinate system being represented.
When specifying this attribute by name, it should be subscripted with the number of the Frame axis to which it applies.