How the discovery of a galaxy inspired a space photo competition

David Malin has spent four decades taking photographs of deep space. His work led to the invention of new imaging techniques and the discovery of the largest-known spiral galaxy - 'Malin-1'.

Now retired, he has held a competition in Sydney, Australia, to inspire the next generation of astrophotographers.

Hear more from Sydney Science Festival with CrowdScience on BBC World Service.