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June 21, 2006

Continuing the theme.

US Collimator, M1, seen through the howitzer sight

Mr. Pogue can no longer play in this round. He's too good!

MajMike gave me a start, when he started out with "collimating valometer..."

If he'd just substituted sight or instrument for valometer, he'd have been the winnah!

But Pogue got it mostly correct. A collimator. He said an early one, but it's actually the current Russian one (though this particular one was made in the Soviet era.) With guys like Pogue playing, and Frank, you'll understand why I didn't put up this picture. Of a US collimator. That would have been waaaay too easy for US Redlegs to get.

If you haven't figured it out yet, the theme this week (and into the next if it takes that long) is "Indirect Fire, How *Do* They Do That!?!" We're introducing most of the major components to get us there from the perspective of the guns. We've already met the Aiming Circle, used to "establish a common direction" i.e., get everybody pointing in the same direction. There are three components to that at the gun level. The aiming circle, the panoramic telescope (the gun's sight) and the Distant Aiming Point.

Let's face it. Infantry sucks. They have rifles, machine guns, hand grenades, and sometimes they stick sharp pointy things on their rifles (we know my problem with *that*!), and alla time they are wanting to sulkily sit around on terrain you'd just as soon they not squat on. They're uncouth, foul-mouthed, and smelly. And generally pissed off. But, if you want to keep them off your terrain, or get back the terrain they already befoul, you've got to deal with them, like any other pest.

But there's no need to actually get *near* them to do this. That's what your own infantry is for. No, you don't want to get near that many troglodytes all crammed into a small space - but that doesn't mean you can't enjoy some nice target shooting. From a distance. With a terrain feature between you and them. Unlike the other arms (whom we love like brothers, I assure you) we artillerymen can actually hit things we can't see, and generally on purpose, too. Oh, sometimes we miss, but that's usually because a Lieutenant, of almost any branch, is involved. And besides, if they're tankers, who cares? That's what 'open protective' is for, right?

So, lets discuss the bits and pieces of how we Kings of Battle keep the Queen in Drag.

And, if you're still here and not ready to kill yourself - go behind the curtain to the Flash Traffic/Extended Entry, where this edition of Gun Pr0n will continue.

Usetabe, back in the early days, you literally selected a distant aiming point, a readily-identifiable spot that all the guns could see, which was far enough away that all the guns had *effectively* a parallel (to each other) sight line. There are obvious problems to that, not the least of which is night time, not too mention terrain. So, very quickly, aiming posts were developed. Once the guns were laid, crews put out aiming posts, two of them, one behind the other, to act as an aiming reference point.

Again, problems with terrain, vegetation, fog, rain, etc - and especially camouflage nets, made that a problem.

Hence, the collimator. The collimator optically simulates a distant aiming point, but can be put right next to the gun - under the camouflage nets. Some, like the US version, have their own light source to illuminate the collimator so you can read the reticle inside. Others, like the russian one - have the mirror, which saves batteries in daylight by allowing you to use ambient light better. Getting an in-focus picture of the sight picture proved beyond my talents, but here is what the russian collimator looks like through the pantel (artillery-speak for panoramic telescope). The picture at the top of the post is a view of the US collimator - and since my light source doesn't work - you can see why that mirror is useful!

If I were a better photog, you'd see something like this:

Collimator reticle

Without going into excruciating detail (I've been told - as recently as lunch yesterday, that I sometimes provide a mind-numbing who-gives-a-flying-fark amount of detail - tough noogies, that's what the scroll bars are for!) the way this all works is the gunner gets the deflection (direction to point the gun) from the Fire Direction Center, sets that number on his sight, then, looking through the sight, traverses the gun until his sight-picture looks like what you see there - when he's done that, his tube is pointed towards the target (not *at* it, but close - but that's another whole series of posts!). We'll leave it at that. You want more detail, enlist in the artillery.

For that to all be accurate, and *fast* in setup, is the purpose of all those fiddly bits Trias was interested in yesterday. There is a sight, so that the cannoneer can literally aim the collimator at the gun's sight, and a level, so that the collimator is level horizontally though the trunnions - that keeps the reticle pattern vertical. There is a way for the gunner to visually interpolate if he has to - but the whole purpose of crew drill is to get it right the first time, every time, so the gunner doesn't *have* to interpolate the sight picture.

That's enough for the day. Soon, we will be moving to the Castle Inner Bailey and tie it all together.