Hi Cosmic & all; Just piggybacking off your post as I did my first Eta Carinae this week also. Used a 500D with a 200mm lens piggybacked on my CPC1100 (not polar aligned yet but hope to be there soon) and was able to stack them in DSS. I have had problems with DSS also in some cases but I think it has been an exposure issue and rejects them if underexposed. For objects where I had good exposures, they stacked fine as RAW files but underexposed would not stack unless I used the JPEG files I saved at the same time (very underexposed Sombrero Galaxy - being a little too ambitious
). I am finding the processing a daunting task in Photoshop CS5, any tips? Thx. Peter