Filming the Great Pit for Return of the Jedi took place in the Yuma Desert in Arizona in April 1982. The French Lucasfilm Magazine (known for it’s rare images not found anywhere else) did a spread on filming this scene in their magazine in 1996.
These rare images have been added to the archives in the rare images section of 1982. I have also uploaded the high-res scans of these images to the forums.