Good start! I can relate to the time required to process the images from an ASI1600. It takes many hours to get the images through the pre-processing, etc. Currently, if I do just one target in a night and have several hundred images, it will take most of the next day to just get them through that initial phase. And if you need to tweak some settings, it can take days.
I'm currently planning to buy/build a new PC that's going to be optimised for Pixinsight processing of these images. While it was getting to the stage where I'd be looking at a PC upgrade sometime in the next year or so, the ASI1600 is effectively forcing me to consider it earlier. It also means that perhaps the true cost of the ASI1600 camera needs to consider the PC upgrades required. However, in my case I think I'll just let that slide.
