|The above image--cropped to get a closer view: Jupiter and three of its moons|
Monday, January 26, 2015
Jupiter and three of its largest moons
I've been using my telescope during January to watch Jupiter and to follow the orbital positions of its four largest moons--Io, Europa, Ganymede and Callisto. These four moons are called the Galilean moons because they were first discovered by Galileo Galilei around 1610. Io is the moon closest to Jupiter, while Callisto is the farthest from Jupiter. Regarding the length of the orbital periods for each moon, Io takes 1.769 days to orbit Jupiter, Europa 3.551 days, Ganymede 7.155 days, and Callisto 16.69 days. This makes it interesting to watch them, because it is possible to see the changes in their positions relative to Jupiter. I've been drawing their positions and at the same time trying to get a decent photo of them and of Jupiter with my digital SLR camera. Despite what I've read online, it's a tricky business to get a good photo, even when I follow the advice given. I plan on taking photos as often as I can; it's not each night that one can do that, due to clouds, fog, precipitation or other interferences that block the view. Some nights, I have been able to see all four moons, but not get a good photo. If I get a good photo of all four of them, I'll post the pic. Tonight I managed for the first time since I got my telescope to get a good photo of Jupiter and three of its moons. I'm posting the original photo and a cropped version to get a better view (a good suggestion from my husband). Enjoy.