A Green Cat's Eye Nebula
Just messing around. NGC 6543 is a bright planetary nebula in the constellation of Draco. Previously I have done a blue version of this, but it is probably more appropriate for it to be cyan or green due to the [OIII] emission.
Some notes on the processing: I combined High Resolution Channel (HRC) and Wide Field Channel (WFC) data to create a more detailed image than before, at least in the brightest parts of the nebula. Furthermore, one of the difficulties with these observations I hadn't realized before is that they were made to test Hubble's ramp filters, and the ramp filter info is buried in the image headers where you have to know to look. I've included it in the channel data this time. The ramp follows the pound sign.
Red: ACS/HRC & WFC FR656N#6725
Green: ACS/HRC & WFC FR505N#5007
Blue: ACS/HRC & WFC FR388N#3727
North is NOT up. It is 35° counter-clockwise from up.