A supernova remnant at an estimated 5000 light years, this is big. It subtends an angle larger than the full moon and so needs a wide field of view.. With the CLS filter in place over the sensor  it takes a lot of exposure to get any detail. The first time I'd tried 7 minute frames...
supernova ic443 la medusa in gemini
700d on 130p    2 1/2hours in 6 and 7 minute expouses @ ISO800