Just got back from the great talk by Prof. Brian Cox (
https://lateralevents.com/public-eve...to-deep-space/).
It was great from an amateur astronomer's perspective. He spoke about how a planets distance can be calculated using parallax. He got one of his amateur mates to image Neptune every night for a month (in Manchester they only got 4 good nights) to demonstrate. He also explained how an amateur can calculate Hubble's constant from redshift via spectroscopy. I learnt a lot that I didn't know about cosmological inflation.