Centaurus A is the nearest strong radio source and is associated with the peculiar galaxy NGC 5128. Special photographic techniques applied to UK Schmidt plates reveal the enormous extent of the optical envelope, which is about 75 arcmin (almost 2.5 times the apparent diameter of the Moon) across its longest dimension. This optical extension does not coincide exactly with the extended radio lobes of the galaxy. Superimposed in register on this deep positive photograph is a negative (black stars) version derived from the same plate without photographic amplification.
This photograph was published in the Journal of Photographic Science . An direct colour image and and unsharp masked view is also available.