U-Boot Periscope Telemeters

[derstosstrupp]

Originally Posted by Nikdunaev

Sorry for the late reply



Simple millimeter paper and no proper rangefinding device? Sounds like a big "ouch" to me.





U-Jagd is not a purpose made tool? Oh...
I honestly thought it was designed for this specific purpose. Those scales look very much like reasonable ship lengths and speeds...

What is the use for depth charging purposes? What do the scales represent in that case?

I am no expert in German, but the name, does it not stand for "unterwasser jagd" or "unterseeboot jagd"? Submarine hunting. Does it actually say if the hunting in question is for or by the submarine itself? I am curious.

By this point I am afraid to ask further. Does the Silent Hunter community actually use any historical tool correctly?



Was it any different from the US optics?
Cause for the latter, as far as I know, multiply or divide by four was the "officially endorsed" method in real life. Both for the stadimeter and the telemeter scales.

The optical zoom, does it not change the angular field of view by that factor? 4 times in our specific case?

Correct, U-Jagd was the term used for hunting of subs, not by. We have the service manual for German ASW as part of the Crush Depth project (in my sig). The word “Annäherung” means “closure” - it’s for timing closure rate most likely, probably to assist in depth charge pursuits. The concept is the same though, distance in m converted to knots.

To your question about there being anything realistic used by the community, yes, these concepts are all historical, it’s just sometimes the devices that are used to get there are a little different than what they actually used. The recognition manual is overused though, that didn’t have that kind of data that these games have, so that’s probably the biggest diversion. And using the manual assumes that the very good vision we have out of the periscopes in game was how it was, and it certainly was not. Viewing a target with the head of a periscope just at the waterline, with fogging, and waves etc. was apparently very difficult. Hence the emphasis on gathering data on the surface while overtaking.

Multiplied by four is correct for 6x, however, there was something with the optics that made that not so straightforward. To the extent that the commander’s handbook recommends rangefinding only at low power.

I can answer the second part of your question to Pisces, only because I know the answer at the ready about the multiple oculars. So the one on the left, with the wire going out of it, inside of that one there was apparently a depiction of the torpedo triangle in colors. This allowed the user to visualize the lead angle. It was linked, at least by my understanding, to the AOB finder, since AOB is an angle in the torpedo triangle (gamma). The only other critical pieces of information are target and torpedo speed, and I’m not clear on how those were entered exactly. The ocular on the top inside of the RAOBF I believe was how the prisms were viewed for the stadimeter.

These sound like great features, and they are very innovative, but with the TDC it’s easy to see how they are somewhat superfluous.

[diego_gut]

"Multiplied by four is correct for 6x, however, there was something with the optics that made that not so straightforward. To the extent that the commander’s handbook recommends rangefinding only at low power."


The zoom and field of view had different ratios, perhaps that made it impossible to calibrate the graticle for both.

[Nikdunaev]

Originally Posted by diego_gut

The zoom and field of view had different ratios, perhaps that made it impossible to calibrate the graticle for both.

Sorry, I am not sure I understand what you are saying

The optical magnification in telescopes is increasing the apparent angular size of an object by a certain factor, compared to what would be seen by the naked eye.
The decrease in field of view, looking through the same eyepiece, is a direct consequence of that, right?

So, it seems that zoom and field of view are proportionally linked to each other by definition.
If not, than the magnification power number is just meaningless.

[diego_gut]

Originally Posted by Nikdunaev

Sorry, I am not sure I understand what you are saying

The optical magnification in telescopes is increasing the apparent angular size of an object by a certain factor, compared to what would be seen by the naked eye.
The decrease in field of view, looking through the same eyepiece, is a direct consequence of that, right?

So, it seems that zoom and field of view are proportionally linked to each other by definition.
If not, than the magnification power number is just meaningless.

In Sh3 it works like you say, there is a direct and inverse relationship between zoom and field of view. However, it is not like that in real life, it depends on the construction of the optical device.


In this particular case, the zoom ratio was 4 ( 1.5 to 6 ) but the field of view ratio was 4.22 ( 38 to 9 ). Since the graticle is just a 2d overlay it can't be accurate for both.


To give more examples, the field of view for the 7x50 binoculars was 7.1 but some 10x80 binoculars had a field of view of 7.25 even though they had 10x zoom. The field of view was different even between different models of the 10x80 binoculars.


What I did for DGUI was to use a 36 degree field of view for the low power, this way the periscopes can be calibrated at both magnifications. This is not historically accurate but I think it is more useful.


Regards

[derstosstrupp]

Originally Posted by diego_gut

In Sh3 it works like you say, there is a direct and inverse relationship between zoom and field of view. However, it is not like that in real life, it depends on the construction of the optical device.


In this particular case, the zoom ratio was 4 ( 1.5 to 6 ) but the field of view ratio was 4.22 ( 38 to 9 ). Since the graticle is just a 2d overlay it can't be accurate for both.


To give more examples, the field of view for the 7x50 binoculars was 7.1 but some 10x80 binoculars had a field of view of 7.25 even though they had 10x zoom. The field of view was different even between different models of the 10x80 binoculars.


What I did for DGUI was to use a 36 degree field of view for the low power, this way the periscopes can be calibrated at both magnifications. This is not historically accurate but I think it is more useful.


Regards

This makes sense. To be sure I rechecked the C/2 manual I have and it indeed only recommends using the graticle at 1.5x.

[John Pancoast]

Originally Posted by diego_gut

In Sh3 it works like you say, there is a direct and inverse relationship between zoom and field of view. However, it is not like that in real life, it depends on the construction of the optical device.


In this particular case, the zoom ratio was 4 ( 1.5 to 6 ) but the field of view ratio was 4.22 ( 38 to 9 ). Since the graticle is just a 2d overlay it can't be accurate for both.


To give more examples, the field of view for the 7x50 binoculars was 7.1 but some 10x80 binoculars had a field of view of 7.25 even though they had 10x zoom. The field of view was different even between different models of the 10x80 binoculars.


What I did for DGUI was to use a 36 degree field of view for the low power, this way the periscopes can be calibrated at both magnifications. This is not historically accurate but I think it is more useful.


Regards

Many times, adding the "historical" figures into a game for most anything causes more problems than it solves.

[Efshapo]

Originally Posted by diego_gut

In this particular case, the zoom ratio was 4 ( 1.5 to 6 ) but the field of view ratio was 4.22 ( 38 to 9 ). Since the graticle is just a 2d overlay it can't be accurate for both.

Hi, sorry to dig up the past but I'm doing some research about periscope fidelity in games.

If the magnification ratio is exactly 4 indeed, I think it's actually possible to get a graticle calibrated for both zoom levels. The field of view wouldn't interfere with the graticle use (it would just mask some ticks that are on the border).

The ratio between fields of view can be different from the ratio between magnification factors. It just means the vignette effect will be different.

Here is an illustration of what I think the observer would see:

Notice that the image disc diameter is smaller at 6x.

What do you guys think?

EDIT:

Originally Posted by diego_gut

What I did for DGUI was to use a 36 degree field of view for the low power, this way the periscopes can be calibrated at both magnifications. This is not historically accurate but I think it is more useful.

What you say is that you used the 6x 2D layout for the 1.5x mode? That would mean the in-game vignette is exaggerated for the 1.5x mode. Did I get this right?

[Efshapo]

Here are my findings so far:

[John Pancoast]

Originally Posted by Efshapo

Here are my findings so far:

Interesting info. to be sure. But I'm not sure a "wrong" this or that is strictly correct.
Real world vs. computer screen, etc.
I'm more of a fan of does something work in the game to simulate it's subject vs. strictly historical specs, etc.
To often, plugging in historical performance specs of equipment, weapons, etc. (which many times are inaccurate anyway, being based on lab specs vs. real world use) causes more problems than it solves in a computer simulation of such. Many times, putting in historical specs for x, breaks function y of some other system, weapon, etc. in a game that was designed to work with the original specs of x.
What is more important is how does it perform in the sim, especially in the "big picture" of the entire sim.
I.e., iirc, GWX's attack scope had a mag of 10x. Historically correct ? No. But a good idea for the limited view of a computer game ? I think so.
Another example is the "pinpoint accuracy" of depth charges originally found in SH3. Historically correct ? No. But it helps make up for the dumb as bricks AI escorts and poor damage modeling. I like it myself, even with the sensor/damage model work since done to the original game, and it's actually not difficult to escape from anyway.

[Efshapo]

Originally Posted by diego_gut

In Sh3 it works like you say, there is a direct and inverse relationship between zoom and field of view. However, it is not like that in real life, it depends on the construction of the optical device.

In this particular case, the zoom ratio was 4 ( 1.5 to 6 ) but the field of view ratio was 4.22 ( 38 to 9 ). Since the graticle is just a 2d overlay it can't be accurate for both.

To give more examples, the field of view for the 7x50 binoculars was 7.1 but some 10x80 binoculars had a field of view of 7.25 even though they had 10x zoom. The field of view was different even between different models of the 10x80 binoculars.

What I did for DGUI was to use a 36 degree field of view for the low power, this way the periscopes can be calibrated at both magnifications. This is not historically accurate but I think it is more useful.

Regards

Kudos to you sir, you win the contest so far:

[John Pancoast]

"This is not historically accurate but I think it is more useful."

[diego_gut]

Thank you!!

[Nikdunaev]

Originally Posted by derstosstrupp

Crush Depth project (in my sig).

That one looks really amazing...

A highly detailed and accurate, historically and physically, submarine simulation, representing the actual particulars of the boat, as they functioned in real life?
Yes, please!

Originally Posted by derstosstrupp

I can answer the second part of your question to Pisces, only because I know the answer at the ready about the multiple oculars. So the one on the left, with the wire going out of it, inside of that one there was apparently a depiction of the torpedo triangle in colors. This allowed the user to visualize the lead angle. It was linked, at least by my understanding, to the AOB finder, since AOB is an angle in the torpedo triangle (gamma). The only other critical pieces of information are target and torpedo speed, and I’m not clear on how those were entered exactly. The ocular on the top inside of the RAOBF I believe was how the prisms were viewed for the stadimeter.

Visualize the lead angle? How was it different from setting the lead angle on top of the bearing ring on the scope tube? The one visible in the "bubble" when looking through the scope?

Or was it automated, with TDC-like functionality?

So, the stadimeter prisms were only visible through one eyepiece, but not through the other, is that right?

Why not just align the ghost image, or move it all the way out of sight, when not being used?

In the scope photo on the first page, the ring sits on the bottom ocular, whereas on the photo above, it sits on the top. Otherwise they seem to be pretty much identical. Is there any significance to that, in terms of functionality?

Originally Posted by Nikdunaev

Originally Posted by Nikdunaev

[Pisces]

@derstosstrupp and Nikdunaev:

You are both talking about this image?
http://www.tvre.org/images/02_fot_07.jpg

[Nikdunaev]

Originally Posted by Pisces

@derstosstrupp and Nikundeav:

You are both talking about this image?
http://www.tvre.org/images/02_fot_07.jpg

Yes, exactly