What have I just bought? It looks like an ADL OMT with a scalar ring but I'm only working from pictures from the web. This one looks similar but with a longer barrel to accommodate the circular polariser: http://adlfeed.com/cat_sec_1_4.htm It's from Australia so I presume it is for linear polarisation. It looks quite rough but I think it will clean up ok. Oh, and if anyone wants it, the seller has a 3m dish for sale/disposal.
View attachment 104111 View attachment 104110
View attachment 104111 View attachment 104110