Prominences, Sunspots and Stamina: Solar Viewing at the ROG - 31 May 2025

We had a fantastic solar viewing session at the Royal Observatory Greenwich on Saturday 31 May, rounding off the season’s meteorological spring events in fine style.

Early cloud cleared by lunchtime, leaving us with relatively clear skies until around 3.45pm, when high haze began to interfere with the view – prompting us to pack up slightly early. But as we’d got started ahead of schedule at 10.15am, we managed to welcome an impressive 600 visitors over the course of the day!

Big queues waiting for their turn at the H-Alpha scope. Picture by Mike Meynell

Temperatures reached around 26°C with high humidity, making it feel more like high summer than late spring – so it took real stamina and dedication from our volunteer team to keep things running smoothly throughout. Thankfully, we also had the gazebo set up, offering visitors some welcome shade while waiting in the queue.

A huge thank you goes to our brilliant team of volunteers: Eddie, Tej, John, Simon, Clive, Alec, Mike, Tony, Margaret, Hayden, and Richard.

Tej has everything under control at the scope. Picture by Simon Hurst.

We’d also like to give a special shout-out to Hayden and Margaret, who joined us for the first time today and really threw themselves into the action – fantastic to have you both with us!

The Sun itself was wonderfully active, showing off plenty of sunspots and some truly enormous prominences – with the vast rail prominence on the north-east limb proving a real highlight for visitors.

And of course, everything stopped at 1pm for the daily ritual of watching the time ball on top of Flamsteed House ascend and descend – even if, truth be told, it’s always a slightly underwhelming display!

The time ball descends. Video by Mike Meynell

This marks the sixth successful solar event out of six planned so far this season – with another nine events still to come before the end of the programme. We’ve already welcomed nearly 2,500 people to our sessions – and it’s not even officially summer yet!

Our next public solar viewing session is planned for Friday 13 June (main date) or Saturday 14 June (as a weather back-up). We look forward to seeing you there!

Pictures from the event (by Simon Hurst, Mike Meynell and Tej Dyal):