Zeiss have just announced that from March this year the Diascope will have LotuTec coating:
http://www.zeiss.de/C12567A80033D63E/Contents-Frame/66132FC8B8415E23C12573B700584E06
http://www.zeiss.de/C12567A80033D63E/Contents-Frame/66132FC8B8415E23C12573B700584E06