... About ATNF overview . ... Australia Telescope Steering Committee . ... Murchison Radio-astronomy Observatory . ... Helium abundances and the N/O ratio in the outer envelope of this nebula are very high, therefore indicating that it corresponds to the evolution of an intermediate-mass stars. ... Some stars show multiple periodicities, e.g. the semi-regular variables R Scl and GM CMa; others, particularly the Miras with moderately thick dust-shells, show more erratic long-term changes. ...