Amateur Astronomers: Sentinels of Jupiter

Thanks to advancements in processing software, imaging techniques, and cameras, amateur astronomers have been able to regularly produce high-resolution images of the planets in the Solar System for about fifteen years. Their efforts are particularly focused on Mars, Saturn, and Jupiter.

They are most often equipped with telescopes ranging from 250 to 400 mm in diameter and are regularly able to obtain images limited by diffraction in the visible part of the spectrum (0.3 to 0.5 arc seconds). These high-resolution images are captured using the Lucky Imaging technique. For example, on Jupiter, the capture rate is typically 50 to 100 images per second, and during processing, the software Autostakkert! 4 helps to correct some of the distortion effects caused by the atmospheric turbulence. Some of these observers use specific filters to produce scientific data. For instance, a filter at 890 nm is used to capture images of Jupiter in the methane absorption band, a UV filter for Venus, or a filter centered at 425 nm to search for Martian auroras.

The most experienced observers share their data across several databases: Junocam, PVOL from the University of Bilbao, the scientific society ALPO Japan, and the Detect program, which aims to detect impacts on Jupiter. Detect has accumulated 74 continuous observation days with 276 contributors, who are spread across the globe. The largest communities are in Europe, North America, and Japan.

The strength of the amateur community lies in its ability to produce daily data and provide almost continuous monitoring of Jupiter. For example, on ALPO Japan, during Jupiter's opposition, new data are added every single day. The number of observers varies greatly depending on the weather; on some days, there are only three contributions, while on others, there are more than thirty.

For amateur astronomers, knowing that their data can serve scientific purposes is an additional source of motivation. It is often very rewarding for them to see their names associated with scientific publications. Additionally, there is a strong sense of community, which has been significantly enhanced by the Juno mission through workshops held in Nice in 2016 and London in 2018, as well as citizen science sessions at the EPSC, supported by financial aid from Europlanet.

It could be valuable to continue fostering this network of observers during the upcoming missions to explore the Jovian system, whether it be JUICE, Europa Clipper or TianWen-4.