Astronomy Photo of the Week - The Best Photo of Jupiter's Great Red Spot Ever Taken

Jupiter reached opposition on September 20th, coming closer to the earth, 368 million miles away, than at any time since 1963. It will not come this close again until 2022. The varying distances at opposition have to do with the fact that Jupiter has an elliptical orbit, which makes its distance at opposition vary. Since Jupiter is at perihelion, its nearest distance to the sun, in March 2011, that makes this apparition particularly close.

In early October Jupiter shines at magnitude ~-2.8 in the eastern sky, just after sunset and is visible all night. Just as nothing beats aperture for fine telescopic views, nothing beats being close to an object for naked eye views. The Voyager I probe was just around 1,149,000 miles from Jupiter when it took this photo of the Great Red Spot on March 4, 1979. That's 320 times closer than the earth was this past September.

This photo is a mosaic compiled and processed by Björn Jónsson.

The Great Red Spot of Jupiter. Photo by the Voyager spacecraft. Processing by Bjorn Jonsson. The Great Red Spot is a giant anti-cyclonic storm (high pressure area rotating counter-clockwise), akin to a hurricane on earth. It is so large that 3 earths could fit within its boundaries and has persisted over 400 years.