Where I have been spending my winters lately, I don't have access to full sized mount, so I have been experimenting with my Star Adventurer. I wanted a little more reach than I can get with an older Nikkor 180 I have. I have this Canon 70-300mm f4-/5.8 which I don't remember trying for astrophotography before. (Would love to have a small very lightweight refractor like a William Optics one to use with the Star Adventurer.) This zoom lens did alright, but the field is not flat at all and even the stars toward the center are not very round. Nonetheless, I haven't done any deep space stuff for some time, so I really have been having fun with this. I haven't used StarTools for a very long while to process deep sky images, and realized I had forgotten how to use it to my previous ability, so that has sent me on a bit of a learning adventure. I downloaded a newer version which has significant new features. I need to give kudos to Ivo Jager, the creator of StarTools who is amazingly available and forever improving StarTools.
I used this lens at 300mm f5.6. This is a stack of 80 65second exposures with 12 darks. I have many more frames which I did not use for this image. Turns out my computer could not handle more than this amount using Sequator to stack. Sequator is so fast and simple, but at least for me it has this limitation. I may restack a larger amount using Nebulosity and see if that improves my final image. Cheers, and thanks for looking.