Sighting in Cape Town, South Africa

What happened: My mother and I were both reading outside when she pointed to TWO sets of three glowing lights moving slowly and gracefully in the sky. They weren't too high, just above the horizon. One of the two sets soon moved away until it was no longer visible, thought the other stayed in view for maybe a minute or so more. It then disappeared only to reappear approx. a minute later then to disappear again. The 3 lights stayed in a fixed formation, they did not stray away from each other. They were consistent and non - blinking, they also moved incredibly slowly - so I have safely removed the possibility of it being any known aircraft. When they first appeared they seemed to be moving across the sky, then as they came into a clearer view they began, what I believe, to move towards the horizon and out of view. We managed to collect a few images but they are fairly poor I'm afraid, though you are able to make out at least 2 of the lights in one or two of them. They were both quite massive in size.

The event happened over the Eversdal/ Durbanville area.