One of the great targets for backyard astronomers is Jupiter, and spotting its moons, the cloud bands and the Great Red Spot is always a treat. Observations over a few days provides a good view into the dynamic nature of the clouds and the orbits of the Moon. I haven’t yet managed to capture the Great Red Spot on photo, but maybe this fall as Jupiter comes back into view in the evening sky, I should make the effort to spot the GRS. This is because ever since it’s discovery in the 1800s, it has been shrinking in size. And at the current rate, it could be gone all together in as little as 20 years!
Jupiter’s Great Red Spot (1995 and 2014) – NASA
In the last 10 years it has shrunk by 3000km, taken a more circular form and increased its rotational speed. Amateur observations since 2012 have revealed that this phenomenon is even accelerating, shrinking by as much as 930km per year. Current measurements have the GSR now pegged at under 15,000km in diameter.
As we head into the fall, Jupiter will become easier to observe. By December Jupiter will be high in the sky around midnight. On February 6th, Jupiter will be at Opposition, fully illuminated by the Sun and at its closest to the Earth.
The photo in the title bar was taken by me back in September 17th, 2010, only 4 days before its closest approach, which shows that even with a small 80mm scope, quite a bit of detail can be captured when the conditions are right.
Ben Backyard Astronomy 