I mean, I´ve seen somewhere there were periscope IR sets that would allow the use of IR from inside the tank ...Why nobody choose this option for their "What if" models and instead keeps using the external sets? Surely, in newly designed tanks, there should be room enough for internal mounting and storage of IR. Is just that it looks "cool"?
Opinions please...

"Active" IR equipement such as that commonly used from the end of WWII to the late 1980's (and still used in some backward places)} requires the target to be illuminated by a large infra-red band searchlight. That is why you see prominent searchlights on tanks of that era like the M48, M60, T55/62, Centurion, etc. From the late 1960's 2nd generation "passive"IR equipment became available which amplified available light. So-called "starlight" scopes. This equipment did not require active illumination of the target which was good since the firer did not have to reveal his position. From the 1980's thermal imaging equipment that detects heat began to supplement or replace active and passive night vision systems. Many early models required fairly large camera's that were often mounted externally such s the British TOGS on the Challenger and Chieftain or the French CASTOR. The technology is now compact enough to include high-quality thermal camera's that are integral to the sighting periscope - examples being the sights used on the M60A3 TTS, M1 Abrams, Bradley, etc.

So its all about technology and timeframe.

I understand the "active" Vs "passive" IR Sights and the Light Intensifier Passive sights. (Not the technical aspect, of course, but indeed the basic principles involved)
German WW2 were active IR so they needed a IR source to illuminate the targets . Hence the need for UHU SdKfz 250/20.
What I meant, and I wans´t obviously able to explain, is that German had already developed a periscopic device that could be fitted to the FG 1253 by 1945. So why should they keep using the extremely fragile IR sights in a so exposed position? And why no one modeling "What If" vehicles has considered that possibility?

I am building a highly modified what-if E100 and came to the same conclusion--combat experience would have resulted in armored night fighting equipment. I am not sure how I will mount the IR gear on my E100, but it will not look like anything done before.

-Doug

Er, because the exposed sights look way cool, man...
That, and the fragile appendages give the late war/Panzer '46 a truly retro/steampunky kind of look.

$0.02

acav out