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Here's another strange coincidence. I own two Jupiter-11 lenses from KOMZ that I acquired separately, but their serial numbers are just 120 units apart! That's not all: my #6502178 is M39 with a distinct purple coating, whereas my #6502298 is L39 with a definitely amber coating. Strange? Yes, but keep in mind that the serial numbers only mean that the two front rings were engraved 120 units after another, not that the glass itself is so contemporary. It might also mean that KOMZ created L39 and M39 lenses in interspersed runs, or that it started counting at #6500000 for both series. Perhaps it also means that multicoating (amber) started around #6502200, which is consistent with my newer lens having the better coating. Or maybe this batch of lenses was contiguously numbered for export to Holland? I guess I don't know what the significance is, but it's cool to find such a coincidence.
The Jupiter-11 is the generic Russian 135mm tele lens, with versions being available in L39, M39, M42, Kiev-10, Kiev-Contax and Exakta bayonet. It doesn't appear to be available today, although you can still buy Russian 135mm lenses, notably KMZ's MC Apo-Telezenitar 135mm f/2.8. The Jupiter-11's optical formula, which can be seen here, shows it has four elements in three groups.
Upon closer examination, my M39 Jupiter-11 has a chipped internal element that either indicates someone dropped it, or that the construction has too much internal tension. Since there are no outer marks, I think it may be the latter.