Darren, I'm not surprised that you are not seeing NGC 5128 with your 8" under bright Melbourne skies. I haven't. Stick with the Moon, planets, bright stars and a few brighter globulars and nebulae under such skies - that is plenty. Save the fainter objects (eg. galaxies) for darker skies. I know some persist trying to observe under such bright skies, using filters etc. Seems to me it's a struggle not worth pursuing when even half an hour's drive from Melbourne's outskirts can get you into much better skies. Particularly when you have the portability of an 8". Eric