They say there are no such things as ghosts but there sure looks like there is one in Cassiopeia. Located approximately 550 light-years away IC 63, a.k.a. the ghost of Cassiopeia is a a nebula being shaped by radiation from a nearby variable star, Gamma Cassiopeiae (Navi), which is slowly eroding away the ghostly cloud of dust and gas (source: ESA/Hubble).
I was not planning on imaging IC 63 but it was finally clear and an OK size for my 80 mm refractor. I ordered a new larger refractor (115mm) a couple of months ago and have been waiting for to arrive. I imaged over three nights although I was only planning on two, however, the camera moved slightly so I moved it back, quickly checked the focus and imaged. When I looked at the images the next day it looked as if the focus was off a bit so I re-imaged after carefully focusing the following night. Turns out the focus seemed the same so I used all the images, I attributed the difference to better clarity the first night.
Processing was basically trying things to see what looked good. I processed the Ha and OIII and combined them into an HOO image. I then experimented with combining Ha and OIII into the green channel at various percentages. I then did an HaRGB but really just used the Ha in place of the red channel. I then did a normal RGB image. After much trial and error, the final image was a combined HaGB with HOO. The HOO was made with 100% Ha - red, 80% OIII + 20% Ha - green, 100% OIII - blue. I then added RGB for the stars.
I have shown just the Ha and the Final HaGB+HOO(0.2/0.8)+RGB image. If you want to see some of the others along the way goto my website at:
https://astroquest1.blogspot.com/2018/11/the-ghost-of-cassiopeia-ic-63-2018.html.
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