Now that comet Pan-STARRS has started to move on after a showy appearance in the twilight skies, it’s time to turn our attention to the next comet that could turn out to be a show-stopper: C/2012 S1 (ISON), generally just called ISON.
The comet was discovered in September 2012 by the Russian observatory called International Scientific Optical Network—ISON—using only a 40 centimeter (16”) telescope. Like most comets, it’s a chunk of ice and rock a few kilometers across. As it nears the Sun the ice will turn directly into a gas, and it will shed dust to form a tail. As the dust and gas around it expand and reflect sunlight, the comet will get brighter, though exactly how bright is hard to say.
The basic stuff you want to know is this:
- Its orbit is nearly a perfect parabola, meaning this is probably its first…
View original post 1,360 more words