You can find astronomy courses on the larger distance learning websites. These sites like The Great Courses, edX, Coursera and OpenLearn generally have several introductory to intermediate level astronomy courses from various universities, which include both the video lectures and other class content such as quizes, worksheets and problem sets. With the exception of The Great Courses these sites offer most of their astronomy courses free of charge if you want only to monitor the course. A “verified” certificate of completion however will cost you typically $50. All of the Great Courses however are pay for courses, though many times, individual courses are put “on sale” for a deep discount. I have taken courses from both Coursera and The Great Courses that have been quite good. However that has not kept me from scouring the internet for truly free courses that are just “out there”...