Most imagers know that the more data the less noisy images are, but for some of us acquiring a lot of data is not so easy, with weather etc.
So combining images done over different years can sometimes be a solution.
Following my recent Soul Nebula I decided to see what i would get if I combined with data from 2019 and when I went to find it I found it itself has been combined with data taken in 2016.
All with different equipment and all imaged from my garden in Bromley:
2016 ED80 and Atik314L (3 hours Ha, 45m Oiii and 1hour Sii) = 4 hours 45mins
2019 SW130PDS and Atik460EX (3 hours 20mins Ha, 1 hour Oiii, 1 hour Sii) = 5 hours 20mins
2022 Atik 460EX and SWED72 Ha 30 x 600, Oiii 15 x 300 binned x2, Sii 15 x 300 binned x 2 = 7 hours 30mins
Total imaging time 17 hours 35 minutes
(https://cdn.astrobin.com/thumbs/3o_2crLGoIhU_2560x0_n1wMX-gx.jpg)
For your info, this is the image from 2019/2016
(https://cdn.astrobin.com/thumbs/TqJzB2hy7RKL_2560x0_n1wMX-gx.jpg)