H-alpha and H-beta imaging of the planetary nebula NGC 6302.

NGC 6302 is one of the highest excitation planetary nebulae known. It has an obscured central star with a temperature estimated at 430,000 K. This paper presents CCD images in H-alpha and H-beta of NGC 6302 and interprets the differences between the images as being due to extinction caused by dust within the nebula. The dust appears to be concentrated in the core, as expected from IR observations. There is no evidence of patchy foreground extinction, although there is a slight difference in the average extinction between the eastern and western lobes of the nebula. A comparison between the H-alpha image and a 5-GHz map gives a dust extinction of about 3.5 to the central star. The outer contours of the 5-GHz map are not in good agreement with the optical images, and further observations at this frequency would be useful.