Thinking of various explanations (exploding comets or motherships) I swapped the camera from scope to the tripod and briefly captured a few images of the very slowly fading but rising object (against the movement of the planets Saturn and Mars which were also in the same area but falling along the ecliptic plane into the western sky).
After about 15 minutes it faded further and the light from the moon made it difficult to see.
This morning I sent the grainy image to the Sydney Observatory “Lights in the Sky” Website and by midday it was clear that a number of people had seen the object all over Eastern Australia and even in South Australia.
Dr Nick Lomb, the Curator of Sydney Observatory believes it to be from a satellite launch, most likely the staging of a SpaceX Falcon 9 rocket used to launch the AsiaSat 8 satellite from Cape Canaveral at 6:00 pm AEST on 5 August. Condensing of the LOX fuel into the extremely cold atmosphere causing the vapour cloud. Amazing to have seen that here in Australia. A very rare and special moment.