Jupiter’s Great Red Spot (GRS) remains a striking feature in the planet’s southern hemisphere, now measuring approximately 10,250 miles (16,500 km) across. Despite this being its smallest recorded size, the ongoing red color makes it a higher-contrast object that can be discerned visually by skilled observers in instruments as small as 90mm. Recent Hubble and ground-based data reveal a 90-day oscillation cycle, where the GRS subtly expands and contracts. Given the possible conclusion of the Juno mission and competition for time on the Hubble, amateur observations are increasingly valuable in monitoring these fluctuations (along with edge “flaking” and internal vorticity changes).

Expert amateur imager Damian Peach’s latest overview notes the GRS’s strong coloration and its interaction with a weak, patchy South Tropical Band. The South Temperate Belt (STB) is especially active, split into two dark sectors – the most extensive it’s been in decades. Segment A lies south of the GRS and Segment G is centered at approximately System III longitude of 180°). The STB has also had a recent eruption just trailing the GRS that is worth watching. Oval BA remains subtle and low contrast in white light, though its center has gained a little orangish color that may be visible in high-resolution amateur captures.

The North Equatorial Belt (NEB) is beginning its periodic recession, and the North North Temperate Belt (NNTB) shows reddish oblong features of interest. And lets not overlook the South Equatorial Disturbance (SED) within Jupiter’s South Equatorial Belt (SEB), roughly centered near System II longitude ~150°–180°. Observers have noted its persistence and visibility, especially in methane-band imaging, where it appears as a bright plume-like feature.

What you can help document through your sketches and image captures:

• GRS size fluctuations: Crisp images when the GRS is on or near the meridian can help document its size.
• GRS edge activity: Larger instruments can watch for flaking or detachment of cloud fragments.
• GRS Color changes: Capture subtle shifts in hue during expansion phases.
• Oval BA structure: Will it perk back up or continue to languish as a harder to see feature?
• STB and NNTB features: Track belt segmentation and oblong formations as well as the recent eruption there.
• Monitor the SED in methane band: Capturing the SED’s morphology and tracking its drift across longitudes could be a valuable contribution.

With the 2025-2026 Jupiter apparition in full swing, observers using 6–14" scopes and lucky imaging techniques can contribute valuable data. Even 4" scopes can resolve the GRS as a pale reddish oval. ALPO encourages submissions of your image and sketches (following our guidelines to help ensure that they are scientifically useful) to Jupiter@alpo-astronomy.org for review by the section coordinator and posting in our image gallery. Remember – your observations help shape our understanding of Jupiter’s dynamic atmosphere!