Seven Needles, 800,000 Haystacks
A quasar is a supermassive black hole in the act of feeding, and it’s so bright that it drowns out the galaxy it sits in. That is a nuisance if you want to weigh the galaxy and weighing it is exactly what you need to do to understand how black holes and the host galaxies grew up together. There is a way round it however, catch a quasar whose galaxy happens to be bending the light of something…
We haven't written up this one. Universe Today has the full story — the link below goes straight to it.