Two days of Solar Activity, Moonlight and Noctilucent Clouds

June 28–29 offered a wonderful mix of astronomical sights. From impressive sunspot groups on the Sun to the year's lowest full Moon and beautiful noctilucent clouds, there was something to observe both during the day and in the short summer nights.

Giant Sunspots on Display

I had the opportunity to observe and photograph the Sun on both June 28 and June 29. Dominating the solar disk were the impressive active regions AR 4478 and AR 4479. Both sunspot groups were large enough to be seen easily in white light and formed the most striking features on the Sun at the time.

Comparing observations from the two days revealed subtle changes in the shape and position of the sunspot groups as solar rotation carried them across the disk. The largest spots were surrounded by extensive penumbral structure, while numerous smaller spots and pores completed the active regions.

The Sun has been particularly active recently, and these giant sunspots served as a reminder that Solar Cycle 25 is still providing plenty of interesting targets for solar observers.

June 28 solar observation showing the prominent active regions AR 4478 and AR 4479.

June 29 solar observation. The evolution and motion of the sunspot groups can already be noticed from one day to the next.

Closeup of AR 4478 and 4479 on June 29

The Year's Lowest Full Moon

On the evening of June 29, a hike close to home provided a beautiful view of the nearly full Moon. From my location, the Moon climbed to only about 11 degrees above the horizon, making it the lowest full Moon of the year. Its low altitude gave it a warm golden-orange colour as its light passed through the thicker layers of Earth's atmosphere.

The combination of the bright Moon, the deep blue twilight sky and the surrounding landscape created a memorable scene during the walk.

The low full Moon rising above the horizon, glowing orange against the twilight sky.

Noctilucent Clouds After Sunset

Back at home, the astronomical show was not over yet. Despite the bright moonlight, a beautiful display of noctilucent clouds (NLCs) became visible low in the northern sky.

These rare clouds form at the edge of space, around 80 kilometres above Earth's surface in the mesosphere. During summer they can remain illuminated by sunlight long after sunset, appearing as delicate electric-blue structures against the darker sky.

The display featured subtle wave-like patterns and fine filaments stretching across the northern horizon. Even with the bright full Moon nearby, the noctilucent clouds remained clearly visible and added a final highlight to an already rewarding weekend of observing.

Noctilucent clouds shining in the northern twilight sky on the night of June 29.

Two Memorable Summer Astronomy Days

It is not often that a single weekend brings together such a variety of celestial phenomena. The combination of enormous sunspots, the year's lowest full Moon, a pleasant evening hike and a display of noctilucent clouds made June 28–29 an especially enjoyable period for observing.

Even during the shortest nights of the year, nature continues to provide plenty of reasons to look up.