of course, although i may have to re calibrate the scales on the AOB finder

Yes I know it is closer to 0.11, thus I wrote in my second post this: So I investigated a bit why that figure was chosen and soon understood that because tan 6.25 = 0,10 it made sense to get range figures. Actually, 5.75 degrees would be even more accurate but apparently the rest of the scale wouldn't then be evenly distributed.

3 marks before the one labelled 10 was what I actually meant. Thus there are 4 in the opposite side but same distance (Before the one labelled "10"), which is certainly puzzling :-?

The only reasonable answer I can think about is that its use is to measure 1/3s or 1/4s of the target apparent length for AOB calculation purposes (I.e. you make a menthal estimation of what the target would subtend in scope marks at 90º AOB and then use the 1/3 or 1/4 divisions to get an approximate figure because approximately 1/4 = 15 AOB, 1/3 = 20 AOB, 1/2 = 30 AOB, 2/3 = 50 AOB, 3/4 = 70 AOB, etc.)

No kidding!! I have given a thought many times to writing a letter to either Reinhard Hardegen or Jürgen Öesten and ask them some questions that have been puzzling me for ages! Only problem is I haven't their mail address :damn:

Observation:

In addition I notice that the upper left quadrant markings of the "real" scope is/are smaller than those in the right hemisphere and lower hemisphere.

The upper left quad appears to be 1/2 a tic shorter, both vertical and horizontal in total length.
(using set of dividers laid upon the screen)

I noticed that too. But it was late and I was tired, so left that for another day to worry about. There must be different uses for these quadrants.

...this makes me wonder about the right & lower hemispheres having anything to do with 36 deg field of view in the 1.5 mag & 9 deg in the 6 mag :hmm:

Last I checked the space between the "10" mark and the central vertical wire of the crosshair was identical on both sides, the only difference being on side is divided in 4 and the other in 5 spaces :hmm: To check this I used a paint program, and copied & pasted one part right below the other to check. Both "10" marks aligned, it was the intermediate space which was distributed differently (4 vs. 5 spaces).

Anyway, the U-Boot commander's Handbook and the scope manuals I have seen state that telemeter scales on the scope are exclusively for 1,5x zoom use. So they are somehow created for providing very quick range estimates (The target is much closer).

If the Devs got it wrong in SH3, that's because they probably didn't go much into technical details with Herr Oesten. I have watched the videos of the interviews, and they talked with him more or less in general terms, not asking specific questions about technical details. They even didn't know that the germans had split prism stadimeters like the americans! and also that the UZO didn't feature any stadimeter inside :damn:, the fixed wire method of speed measuring, and many things more.

Undoubtedly, they didn't ask Oesten about that :shifty: but rather spent the interview time talking about things that could have been easily found elsewhere :cry:

Do you suppose, Hitman, that they are simply "Stadiametric Rangefinding" as in MilDot?

i.e.,

1 mil = 1 milliradian
3.1415926 rads in 180˚
1 mil = 0.05729 degrees or 1/6400 (Nato), 1/6283 standard civilian rifle scope <--(note 2∏=360˚) 2∏ also = 6.283.


then

Range in meters = Mastheight in meters x 100 / # of tic marks in the 1.5x magnification ?

If this is the case, Trigonometry is not needed to guesstimate range through the scope.

My personal binoculars uses the same system with their built-in reticules.

I just checked this out in the "Naval Academy" and measured the C2 mastheight as 2 tics in the "convoy attack".

using the above formula:

24.5m (x100) = 1225m range.
2 tic marks

when I use the NLSR scope the mastheight measures 4 tics as it doubles the objective view with the mods I have and I measure 612.5m (x2 = 1225).

Yes I'm pretty sure it is a simplified form of stadiametric rangefinding, but I can't see the logic behind the current scale divisions. I know the "10" mark is 6.25 degrees, though, and that makes sense for scales divided in 1/16 of a degree (Where the tenth mark would be 6.25º) like this one here (This is from a late war model observation scope):

http://aycu02.webshots.com/image/290...3651716_rs.jpg

In this one the horizontal marks are in degrees. And the 10 has in fact the degree symbol. The vertical ones are however 10/16 of a degree, and serve obviously for stadiametric rangefinding since this periscope model apparently had no split prism stadimeter/rangefinder.

But I find a bit too complicated the other markings placing :hmm:

Anyway, this all might be related to a printed table or a special ruler that the user had to calculate values quickly. But I would like to get the full sense of those marks anyway :up:

BTW I forgot: Here is some good information for those interested in military uses of stadia-rangefinding: http://files.thetallengineer.com/Ran...ation_Rev1.pdf

Hitman:

What is that symbol halve way on the left of the vertical scale in that orange scope drawing? Can you get a better resolution on that?

It reads "/16º"

As I told you, it means that the vertical scale marks are separated by 10/16º of a degree, or 0,625 degrees each.

Judging by your excellent graphics of the manual:

my sense of it is this, caveat, I am not an engineer...


-
-
50-- - - - - - - - - - - - -
-
-
-
-
/16˚____________________________|_____
-
-
-
-
50-
-
-

Given: each tic = 10/16˚ = 0.626˚, then,

If the baseline were @ the waterline and the masthead(25m) were @, say the 50/16 mark--

then it seems reasonable that:

25m (x100) = 800m range
(50/16)

Why the C.Zeiss engineers at Jena chose ( /16˚) could perhaps have been to surmount an engineering variable/obstacle (focal length, calibration, power of magnification, parallax...who knows what?)

What's confusing to me is, does that "/16˚" apply to both scopes?

Hi all
Interesting subject.
Analysing all your data, I see you have solved it.

The Newer version uses /16 for ease of use and greater accuracy (more divisions). But still uses the old horizontal measurements (perhaps accuracy is not so vital).

The old 10 mark=160 on the new scale 160/16 that would probably account why the 160 mark is the last mark above horizontal line and the thick lines centre top bottom are present.

50 marks (50/16) on new scale would be roughly equal to 3 on the old scale.

so if we had a mast of 25m

old scale
(25*100)/3=833.33m

new scale
(25*100)/(50/16)=800m

As stated previously, more marks allow greater accuracy.(unless you add the between mark value).

This would apply to both scopes and UZO (even though the UZO had a different magnification).

I wonder
 

You know, if the subs used the height of the mast to get the range to the target ships, why didn't the allies use differing heights and vary them frequently to confuse the range finder? Or did they?