I've been trying to figure out just what the "periscope" looking thing is in front of the commander's hatch is on the 2A6. It appears to be aprox. 1.5 ft. wide, 6 in. high and 6 in. thick, and looks like it might be retractable.
On Tamiya's 1/35 2A6, it's shown in step 18 - part C10, with 2 "D" clear pieces.
Since it looks like it's totally transparent, is it possibly some sort of "head's-up display" for relaying info to the commander while he's up in the hatch?
Just a question that's been bugging me for a while.

It is the gunners primary site, amongst other functions. Does not retract, but does have armoured shutter doors.

I know what you're talking about, but it's not that. The thing I'm talking about is just in front of the commander's hatch, say, only a couple of (scale) inches. Should have specified how close it was - sorry.

Are you talking about the armoured glass vision block in from of the Commander's hatch? It is not retractable. It simply permit the Commander to have a bit of ballistic protecting while observing with his head out of the hatch.

Thanks!
I kind of figured that's all that it was.
Guess that's why the TC's hatch raises up then rotates horizontally rather than flipping back like the gunner's.
Would have been interesting if it HAD been a repeater display for the gunner's thermal sight in a heads-up format or even just a basic "dashboard" done the same way, though.