IC 443, communally known as the Jellyfish Nebula, is located in the constellation Gemini at an approximate distance of 5,000 light-years. The nebula is classed as a shell type supernova remnant created by the explosion of a massive star about 30,000 years ago. The nebula is expanding and currently it is about 300 light years in diameter and extends over an area of sky almost twice the size of the full moon. The bright star to the right of the nebula is Eta Geminorum. It is a naked eye foreground star approximately 380 light-years from the Earth and is not associated with the Jellyfish Nebula.
The image above is known as a mapped, or false, color image and was acquired using narrowband filters. It was assembled using the standard Hubble palette with SII mapped to red, Ha mapped to green and OIII mapped to blue.