I'm going to be retiring next year. I have an ST10. I would like to get a new camera that closely matches the specs of the ST10. One thing is that it has to be NABG, & the size of the chip should be close to the same. I'm going to use it on a 18" f4.45. I was looking at the STXL6303e, but I'm afraid with the size of the chip, I'm going to get star comas near the edge of the FOV. I also need it to be compatible with an AO unit. I have been away from AP for a while and with cameras changing so fast, I haven't been able to keep up. What model would I be looking for?