Left: H. Right: [OIII] with its central "spider-shape". Nitrogen is not detected along the ring, but only in the centre (see below)

The almost perfectly spherical structure seen in H image would suggest a uniform shell, except the four enhanced emissions, however, along the ring. In addition, the [OIII] image displays a filamentary network around the condensations of the inner regions, with much more details than the previous image by Jacoby 1979. This inner ``ansae'' region is surrounded by a fragmented ring of 20". The [NII] emission consists simply of two or three small knots near the central star and the ring shape is no longer present in [NII].

Monochromatic images of A30´s centre in H,[NII],[OIII]

Credit: C.T. Hua and S. Kwok (1999)