We have a lot of astronomy lectures - worth using search if there is something specific you're looking for. 

General

Cosmic Concepts series Katherine Blundell

Why Society Needs Astronomy and Cosmology Roberto Trotta

The Nature of Reality series Roberto Trotta

In the Beginning Joe Silk (the early Universe, the Big Bang etc)

How Special is Our Universe? Joe Silk

Are We Alone in the Universe? Joe Silk 

How Common is Life in the Universe? Joe Silk

Dark Matters Joe Silk

Elementary Particles and their Interactions  Joe Silk

Ultra-Compact Objects: Astronomy with Gravitational Waves Joe Silk 

The High-Energy Universe Joe Silk

Issues

Existential Risks in the Solar System Joe Silk

The Moon

50 years of Lunar Exploration Joe Silk 

Great Astronomers/ physicists

Caroline Herschel Discoverer of Comets Sheila Kanani

What has Einstein ever done for you? Roberto Trotta