You probably didn’t need me to tell you this – but our worlds are moving!
I was working on some images of Saturn that I collected on September 19th and noticed its rings were in partial shadow, whereas the next most recent image showed no shadow at all.
We know that the orbit of Saturn is huge compared with that of Earth. Saturn is about 9.6 earth distances from the sun and it takes about 29.5 earth years to orbit the sun. All the while our little planet is whirling around the sun in just 365 days.
So our view of Saturn changes throughout the year and it’s apparent not only in the position of Saturn in our sky.
Saturn reached “opposition” – opposite the earth from the sun on August 2nd. As we looked towards Saturn that night, the Sun was behind us and shining straight onto the face of Saturn from our vantage point. The left image was taken around that time.
Fast forward to mid September – one and a half months later. We had scurried around our orbit to a new position – one in which we see Saturn from a slightly different angle. So in the right image above, we get to see a little bit of Saturn’s shadow cast on the rings behind the planet. It’s pretty cool to see the changing solar system from a home telescope!
And I thought those rings were only in books!
Both of the images are the result of collecting thousands of frames of data into a short movie and then combining a few percent of the best single frames from the movie. The frame rate was about 30 frames per second. The August image was taken in Vermont at the Stellafane amateur telescope makers convention, while the September image was on a rare night of “decent” seeing here at Norton Cemetery in Keene, NY.