I recently purchased a copy of MIL-HDBK-141 on Optical Design. I've seen it regularly in discussions of the design of optical systems. It's about 750 pages. I scanned it and converted it into PDF files. There are six of them, but they are still large (11 to 17 Meg.) I posted them on my web site at: http://www.azmackes.net/astronomy/mil_hdbk_141 If there is much demand, perhaps we can find someone to make some CDROM copies. If you want to purchase a hard copy, I got mine from the Surplus Shed http://surplusshed.com It was $50.00. Joe -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.