Hello, I'd like to practice various image correction approaches in ENVI, specifically geometric, radiometric, and atmospheric. I have run through the tutorials provided by ENVI online. They are all good and well but I would like to give it a shot on my own. What I would like to do is retrieve imagery for each of these correction processes. Most of the Landsat data I find has already been geometrically corrected. The areas for which non-registered Landsat imagery (L0) is available are those for which I have little high-accuracy data to conduct registration. Does anyone have any recommendations on where to find free, downloadable imagery that would be appropriate for these correction procedures? Thank you.