The Sun today - 07_09_2025

 

The Solar photosphere captured in white light
using - the JPO's 66mm.Altair Lightwave ED refractor, A Baader safety film objective mounted filter, a QHY5lll462c video camera with stacked UV-IR filter and green light filter. All on a Star Adventurer EQ mount.

"The JPO team was all out today getting kit organised for imaging the eclipsed Moon tonight as it rises above the North Sea horizon from Pakefield Cliffs. Sadly, as the day has gone by the clouds have rolled in and the chances of seeing anything of the eclipse tonight appears to be remote. 

Anyway the clouds did stay away long enough  for Kurt to capture some photons of our nearest and dearest star, 'The Sun'.

We certainly captured a lot of sunspots in the two x 1 minute video clips we took on the day.

We tried, for the first time, using a green filter stacked with our usual UV-IR filter as we had been advised that this can help to resolve more sunspot detail. We think this was the case but a red filter similarly stacked is better for 'show-casing' faculae.

Just take a moment to look at the above image and take in that the Sun's diameter (at the level of the photosphere) is 1.39 million km. By comparison the Earth's diameter measured at the Equator is just 12,760 km. The Sunspots appear tiny in the image but in reality could swallow the Earth whole"

The Solar Photosphere and current Solar Activity

• The photosphere is the Sun’s visible surface—the layer that emits most of the light we see—spanning just 100–400 km thick, with an effective temperature near 5,772 K 
• In this layer, convection emerges as a granular texture - if you look carefully at the above image you can see the granulation:
• Granules—tiny, boiling convection cells—are around 1,500 km in diameter, lasting up to 15–20 minutes 
• .Larger supergranules span up to 30,000 km and last about 24 hours, driving magnetic field flows 
• The photosphere’s granulation drives the movement and emergence of magnetic fields that define sunspots and active regions.

Sunspots & Magnetic Suppression

• Sunspots are cooler (~3,500 K vs. ~6,000 K of surrounding photosphere) due to intense magnetic fields that inhibit convection, appearing dark 
• These strong magnetic structures form the roots of magnetic loops that extend into the chromosphere and corona, often associated with solar flares and energetic events 

Current Solar Activity (Summer 2025)

• As of now, the Sun is in Solar Cycle 25, which reached its maximum sunspot activity around late 2024, with numbers around 160 for smoothed monthly peaks 
• .Recent measurement show sunspot number around 108, with new active regions emerging and moderately elevated 10.7 cm radio flux (~146 sfu) 
• However, activity is gradually declining from the peak, with solar flux levels about half of the cycle’s peak by mid-2025 
• .Daily sunspot counts have varied—ranging between ~130–154 in early August 2025"

-Karl Segin outreach coordinator at the Jodrell Plank Observatory.