Please say more. How does a software engineer with a data engineering background and interest in astronomical phenomena learn about/start contributing to this area?
There is plenty of opportunity to contribute to open-source —-astropy is one of the most active projects, as a starting point.
Deeper (volunteer) engagement probably requires finding a willing scientist to plug you in to a project. That can be tricky get going and to make mutually beneficial.
There are full time research software engineer positions—these will pay less than industry, of course; for some folks the subject matter and environment make that trade worthwhile.
I do remember seeing a website that attempted to connect SW engineers willing to volunteer with scientists but I think that effort died out. Not a bad idea.