Panther Fibel Discussion of Range Estimation

[rexford]

Originally posted by Mr. Tittles:

This pic shows that a Hornet (Nashorn) appears to have a Scissor scope.

In Panzer Aces, the crews are described using scissor scopes.

And that pic shows a much shorter baseline between arms than 90cm, so the relative accuracy would be less than ideal (or as originally quoted on this thread).

[rexford]

Originally posted by Mr. Tittles:

Here's an excerpt from '7000 Km in a Sturmgeshutz' (Heinrich Engel -Knights Cross holder)

I let the cross-level settle down and corrected the range "1700 m, Fire when ready!". Observing through the scissors telescope, I followed the 2 second tracer path of the AP round. Closer and Closer it came to the tank-a hit!. The turret flew some distance away and the tank burned!

The author, a StuG TC, is clearly describing using a scissors scopeto measure range. He is the one that orders the corrected range to the gunner.

I'am not so sure that the scissors was used to "measure" range, since the scissors were used to observe fall of shot after "letting the cross-level settle down" (which means what?).

Anyway, if scissors scopes are not used in the fully extended arms manner, which it appears they usually weren't, they would not appear to "measure" range as much as "estimate" range since the accuracy would be less than optimal.

Any idea what the decrease in accuracy would be when scissors scopes are used in the normal, relatively "arms close together" manner that the pictures suggest?

[rexford]

Daniel previously mentioned that a target at 500m with 2.5x gun sight magnification would appear as if it were at 250m. The actual range would be 200m (500m/2.5).

A 3m x 3m vehicle at 500m using 2.5x magnification would appear to be:

3m x 12"/200m, or 0.18" (0.46cm)

on each side.

Using scissors scopes, the same target would appear to be:

3m x 12"/(500m/14), or 1" (2.54cm) on each side.

To see what the above dimensions mean, hold an object the same size as the above calculations 12" (30.5cm) in front of your face. The above calculations are based on the relative size at 12" from the eyeball.

As an aside from the above calcs;

given the relatively small percentage of the general population that is able to make full use of the stereoscopic rangefinder, what are the chances that every StuG III, Nashorn or Panther crew had such a visually capable crewmember able to use the sight in a fluid, combat situation?

[Mr. Tittles]

No one has shown data that these scissor scopes HAD to be at full angle to be used as stereoscopic range finders. In fact, I am starting to suspect that they worked by varying the angle. I have seen them at many different angles. If they had to be at full horizontal to be used as rangefinders, then why vary the angle at all? Why not leave them just vertical?

And its already been shown that they could periscope up and clear the holes on the vehicles. Please, again, try to review the thread and catch up.

These scissor scopes, like mono-gunsights, have a level bubble. Again, look at the pictures closer.

In Panzer Aces, the section on Albert Ernst (Hornet, JagdTiger) also shows he used scissor scopes to guage range. Including some very long range shooting with minimal round expenditure.

I would dare say that to be a StuG TC, you would have to pass some course using these scopes. Perhaps only panzer platoon commanders may have needed to do that. Some people may be able to do it better than others? No kidding. Thats why there are standards of performance to pass a class.

These scissor scopes were multifunction items. They could be used as periscopes and as stereoscopic rangefinders. Its almost certain they are more expensive to make them than a mono periscope. One lens could be replaced with a 20X lens to make a super spotting scope.

[ August 05, 2004, 03:52 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

General Army Communication of June 7, 1941:

'Use of binoculars and scissor telescopes at night. It is to be

noted that at night, the distance of effective observation of the

unaided eye can be doubled with the 6x30 binocular, and about tripled

with a 10 x 50 binocular or a scissor telescope O.K.H. (Ch H Ruest u.

BdE), May 31, 1941. 79 ln4 (IIIb)'

An important part of an S.F. is the reticle, which was mainly needed

for target shooting at sight, for artillery measurements, and for

estimating distance. The reticle is placed in the image plane of the

ocular, so that the scale and the observed image could be seen at the

same time, similar to the cross hairs of a rifle scope.

During the first World War, there was a diversity of reticles; but

the later reticles, of the Reichswehr and Wehrmacht, were mostly

standardized. During this time, a new reticle was developed: the

Gitterplatte [grid plate], initially used for special purposes. The

authors cannot give an exact date for the introduction of this. [page

197] In the paper by Kaiser (1918), the 'well known grid-plate' is

mentioned, and therefore some S.F.s were equipped with the grid plate

during the first World War. The S.F.s with ‘existing’ reticles were

known as 'SF 14 Z', and the S.F.s with grid plates were named 'SF 14 Z

Gi'. From the outside, the two models are indistinguishable. The grid

plate, see fig. 115, was of such great benefit that during the second

World War, it was used almost exclusively. The grid plate was the

characteristic mark of the German S.F. of the second World War. From

the Army instruction paper of January 1937, it can be seen (in the most

beautiful language of officials), that the grid plate was generally

built into new instruments only after this point in time.

[ August 05, 2004, 03:09 PM: Message edited by: Mr. Tittles ]

[flamingknives]

Originally posted by Mr. Tittles:

No one has shown data that these scissor scopes HAD to be at full angle to be used as stereoscopic range finders. In fact, I am starting to suspect that they worked by varying the angle. That is, as you adjusted the focus, the arms would swing out. The only real need for having them all the way horizontal is for extreme range.

No, I think that the angle is independent of other functions, but the wider the angle (and hence the baseline) the better the accuracy of the measurement. The mechanism that dealt with the convergence of the images would have been a pivot between the two monocular sections that made up the base binocular.

Regardless of its accuracy, it is still a measurement as opposed to an estimate.

[Mr. Tittles]

Yes I edited my post also. My main point is that photographic evidence shows they are being splayed out. Angling them all the way out may have been overkill for most AFV needs. Measuring range to +/-100m being sufficient for most HV guns out to 2500m or so.

[ August 05, 2004, 04:02 PM: Message edited by: Mr. Tittles ]

[Bogdan]

Originally posted by Mr. Tittles:

I find rexfords claim that...

The Panther 75mm would still miss more often than not at ranges beyond 700m, and it would be expected that the gunner might have as good, if not better, range estimate than the commander if the triangles were used. Two heads are better than one if the driver cannot see the target (a hulldown position would almost automatically limit or rule out a driver range estimate, especially if the tank were hidden in the brush).

..to be somewhat odd. He seems fascinated by this averaging method. I have never heard of anyone using such a method.

Dear ballistic specialists, here is what I found on the TigerFibel :

...and its english translation :

Also :

and the english version :

Then, I really don't know if panzer crews applied this method during combat (which seems to be quite long in an engagement), but they look to have at least learned how to guess a range together... :confused:

[Mr. Tittles]

Its wierd. They make such a big deal about the Strich method and then they claim that you can't approximate range with one eye. In any case, I have read so many accounts and WWII tank warfare is pretty much what Jeff described earlier.

Its apparent that this 'method' is for long range shooting. It would not be used for shorter ranges. The gunner using his Strich method would be better for less than 1000m.

Another thing I find odd is this 'adding to the range'. This adding is needed because you want to hit the enemy tank and not have the AP land at its feet.

Were the guns actually zeroed like that? Seems to me, I would zero a gun so that it would hit a enemy afv sized target in its center.

The drill would be:

1. Rough in boresight at 25 or 50 meters

2. Set up target at 1000 m (2.5m x2m)

3. Shoot/adjust AP so that hits target in a group in its center

This way, if a enemy AFV is seen and its range judged to be 1000m, then fire at 1000m! Its almost as if the guns are zeroed for HE (where you DO want the round to land at the range).

[ August 06, 2004, 07:23 AM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

I have seen these SF being used by artillery units and they are not splayed all the way out either. That Germangoy guy has a website about a relative and his arty experiences in WWII. I believe there is a photo looking through a SF also.

[flamingknives]

Germanboy: AKA Andreas.

ISTM that the advantages of using both eyes is largely negated by the time you get 1000+ metres. The eyes work like stereoscopic rangefinders but have a baseline of 2-3" so at long ranges they cannot use this to discern range any more accurately than one eye. You're reduced to working with "well, it looks this big, and I know it to be this big" or what have you.

[danielh]

I found some interesting info in Schneider's "Panzertaktik"

In Tankerschool (end 1943) the crews had to fulfill the following:

1st Exercise:

Using HE on a target at unknown range but less than 1200 meters. Own tank stationary target stationary (size of AT-Gun)

Criterion to pass: 1 Hit out of 4 rounds

2nd Exercise:

HE on a target at range greater 1200m, six HE rounds authorized (target the same as in 1)

Criterion to pass: 1 Hit

3rd Exercise:

AT round on a (stationary, frontal) tank target at greater than 1200m. 4 rounds authorized

Criterion to pass: 1 Hit

4th Exercise:

AT round on a moving (ca. 20km/h) tank target across the field of vision at 800 - 1200m. 3 (!!!) rounds authorized

Time: 30 sec. Firing time, target moves 150 m

Criterion to pass: 1 Hit

Notice: No Examination on tanktarget stationary below 1200 m !! (Because a first round hit is almost certain)

The book also in detail describes the firing procedures. It notes that for armored targets at ranges less than 1200m no aquisition firing is made (bracketing and the like), but instead immediate fire for effect is done. It starts with a 200m addition to the estimated range. If the first round is over the target (Gunner observes tracer of the AP-round), then 200m are substracted. If the first round is short the aim-point is corrected, if the next is also short then the error is much greater and the target is at a range greater than 1200m, therefore bracketing has to be used (Aquisition firing).

During exercise, firing is normally directed by the commander, however out in the battle the Gunner will engage targets of it's own. As soon as a target is identified by the gunner, he immediately calls out "Panzer", takes aim, warns (Achtung!) the crew and fires.... This is done by the Gunner until the Commander overrides (He can actually order the Gunner after the calling out "Panzer" and "Achtung!"(before actual fire).

So the firing procedures were straight forward and flexible.

Further as a rule always an AP-round was loaded in the gun on entering the battle, and the range set at 800m or 1000m.

Greets

Daniel

[Mr. Tittles]

I would assume that was for 75mmL48 weapon?

[danielh]

Hi Mr. Tittles

(Good and interesting stuff from your side, thx !)

Sadly, nothing is mentioned about the gun, however i also suppose the 75mm L/48. In Jentz's Panzertruppen there's a fieldreport about the Panther D's performance in the field, and there it is mentioned that it could be expected to hit enemy tanks out to 1500m with first round with high probability (Fire for effect immediately i suppose..)

To Rexford,

One should go outside and observe for instance cars on the street to really estimate what size targets seem. Example: A Car 1.5m in Height 100m away when projected 0.3m away:

1.5m x 0.3m/100m = 0.45 cm (seems extremely small, but it isn't for the human eye, rather big instead one can identify every detail...., or do you have trouble seeing a car 100m away ??? (I have no trouble to spot them out to 4km, and can certainly identify them up to 500m). Or if i take my 1/35 scale Panther and put it 20m away (effectively 700m), i have no problem to identify it in the open (Ok, here my stereoscopic sight also comes into play). Tank at 1000m with 5x Magnification (3m x 0.3/1000m x 5 = 0.45cm) is a big target ! Btw. 2.5cm (with the 12x Scissors) is like my 1/35 scale tank on the table, huge !

Greets

Daniel

[flamingknives]

Danielh: if I look at my house (>10m tall) from 100m away, it isn't as high as a 30cm ruler held at arms length. Objects at 1000m (approx) through my 12x rifle scope aren't that big, so I think you've made an error in your calculations.

[Andrew H.]

1. My understanding is that the scissors scope is *not* a stereoscopic rangefinder, but a trigonometric rangefinder. Everything I've read, including the photos of the rangefinders, seems to bear this out. Trigonometric rangefinders are based on the principle that you can determine the distance to the apex of a triangle if you know the distance of the triangle's base and you know the two angles. When you splay out the rangefinder, you know the baseline distance. I believe that the angle of one side of the scope was fixed at 90 degrees, and the other angle was adjustable via a knurled knob. Once you have this angle, you take its tan and multiply it by the baseline to get the distance to the target. For this method to work accurately, you really need to be able to measure the angle to three decimal points. If there is something you read off on the inside of the scope, I suspect that it would be the precise angle measurement - the readings on the knurled knob aren't find enough.

FWIW, at ranges between 1000 and 2000 feet, accuracy to three decimal points (with a 1 meter baseline) finds the range to within about 30 meters. Accuracy to two decimal points finds the range to within about 300 meters, which could still be useful.

I suspect that the rangefinder needs to be at full horizontal extension so that it can accurately measure the angle with the proper amount of precision. It's possible that the scopes did this, although it would be quite complicated mechanically. FWIW, halving the baseline doubles the error; quartering it quadruples it, etc.

2. The scissors scope would still be useful for determining range even when not used as a rangefinder. That's because if you increase the distance between the objective lenses of a pair of binoculars, you increase the ability of the user to perceive depth. That's one reason why binoculars are built the way that they are - the eyepieces are where your eyes are, of course, but the objective lenses tend to be further apart from each other. With scissors scopes spread to a half or a third of a meter distance, the user's ability to tell whether the shot landed in front of or behind a target should significantly improve. (More precisely, they should have the ability to see in 3d at ranges where they usually could not).

[danielh]

flamingknives,

I didn't say the targets are big in absolut measure, as shown by the example of the car 100m away, 1.5m Height, projected at ruler distance (0.3m) = 0.45 cm -> which is small absolutely, but still quite big, for one can clearly make out the car and it's detail ok ? One has to imagine that the picture projected on the retina is also very small, even more the area of sharp sight....

What counts is the relative size things have to each other as we are accustomed in everydays live.

And to the objects 1000m away on an unobstructed open plain, objects are certainly easily recognizable atleast if they are 3m tall.

Of course light(hiding in shadow), partial cover by terrain or foliage (masking) makes target recognition certainly difficult at much shorter ranges (-> Normandy hedgerows for instance).

Greets

Daniel

Greets

Daniel

[Mr. Tittles]

http://www.deutscheoptik.com/rangefinderinstruction.htm

In Tiger Tanks-Michael Green, the British report that early Tigers were found with coincidence type rangefinders in them. The coincidence rangefinders were very similar to the ones used by light flak. This book also states that the SF type scissor scopes were used later.

It also mentions that German binoculars had some type of 'strich' type marks in them.

[ August 06, 2004, 09:40 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

An unusual rangefinder in the form of an S.F. is shown in fig. 118.

This model, developed in Germany during W.W. II, served to measure

distance, and to observe at the same time. It is less prone to

misalignment, and can be used from behind cover. Between the two

objectives, there is a ‘waagerechter Kollimationsstrahl’ [balanced

refracting collimation device]. This stereoscopic rangefinder was

produced by Zeiss (blc) and Busch(cxn) until the end of the War. For

details about this 'Disvau' (Zeiss) 'rangefinder of rugged

construction', see Koenig/Koehler 1959, page 411. After the war,

production under the name Em 61 [rangefinder 61] was continued in the

area later known as the Eastern block. It is not clear if only Zeiss

Jena produced them, or if they were also made at different places.

Later models, similar but of larger and smaller construction, were

added. These instruments are modified from the wartime models, for

example some were supplied with light amplification, see fig. 119.

[flamingknives]

Originally posted by danielh:

flamingknives,

I didn't say the targets are big in absolut measure, as shown by the example of the car 100m away, 1.5m Height, projected at ruler distance (0.3m) = 0.45 cm -> which is small absolutely, but still quite big, for one can clearly make out the car and it's detail ok ? One has to imagine that the picture projected on the retina is also very small, even more the area of sharp sight....

What counts is the relative size things have to each other as we are accustomed in everydays live.

And to the objects 1000m away on an unobstructed open plain, objects are certainly easily recognizable atleast if they are 3m tall.

Of course light(hiding in shadow), partial cover by terrain or foliage (masking) makes target recognition certainly difficult at much shorter ranges (-> Normandy hedgerows for instance).

Greets

Daniel

Greets

Daniel

I see, my mistake. I read through with consistant units, so when you switched to cm, I didn't pick up on that and thought that you meant 0.45m. Which is silly.

[rexford]

Originally posted by danielh:

Hi Mr. Tittles

(Good and interesting stuff from your side, thx !)

To Rexford,

One should go outside and observe for instance cars on the street to really estimate what size targets seem. Example: A Car 1.5m in Height 100m away when projected 0.3m away:

1.5m x 0.3m/100m = 0.45 cm (seems extremely small, but it isn't for the human eye, rather big instead one can identify every detail...., or do you have trouble seeing a car 100m away ??? (I have no trouble to spot them out to 4km, and can certainly identify them up to 500m). Or if i take my 1/35 scale Panther and put it 20m away (effectively 700m), i have no problem to identify it in the open (Ok, here my stereoscopic sight also comes into play). Tank at 1000m with 5x Magnification (3m x 0.3/1000m x 5 = 0.45cm) is a big target ! Btw. 2.5cm (with the 12x Scissors) is like my 1/35 scale tank on the table, huge !

Greets

Daniel

Sir, I have written some papers on the relative size of targets and objects when they are various ranges based on theory and experiments. Also did studies on visual range estimation curve shape and probabilities, based in part on estimating range to cars on street using eyes alone (no comparison to what it should look like).

Your figures in an earlier post appear to be incorrect, although the recent calculations look right.

If 3m high target at 1000m is associated with 3 mils, the same height at 800m would look like 3.75 mils (you said 4.5 mils in an earlier post). At 1200m, the 3m height would appear to be 2.5 mils (you said 2.25 mils).

The math for 3m height at 1000m and 800m (measured 12" in front of eyeball) would result in:

3m x 12"/800m = 36"/800, or 0.45"

3m x 12"/1000m = 36"/1000, or 0.36"

A 25% difference in observed height (3 mils vs 3.75 mils is 25% difference), whereas you had 3m mils versus 4.5 mils (50% difference).

You appear to have it right now but earlier post looks like something went haywire. Maybe you should go back and correct your earlier post on this thread.

Lorrin

[rexford]

Daniel previously brought up the issue of how gunners could estimate an 800m or 1200m range for a tank target that was 3m high when it would look 3 mils high on the gunsight (and when compared to the 4 mil high triangle).

Typical target heights follow, and few are exactly 3m high:

IS-2, 2.7m hi x 3.1m wide

KV-Is, 2.8m hi x 3.3m wide

T34 M43, 2.7m x 3.0m

T34/85, 2.7m x 3.0m

M4A3 Sherman, 2.9m x 2.7m

The above heights include any narrow protruding objects like periscopes, which might not be very visible at 1000m range with 2.5x magnification.

None of the above potential panzer targets is 3m high, and if one limits the height to solid and wide areas the real observed height might be somewhat less.

There is also the possibility of small ground curls and folds blocking out some of the tracks or lower front hull.

Assuming a 3m target height comes with built-in errors, and would seem to result in high range estimates by the gunner.

If one assumes a 3m width, and the vehicle hull is angled to the firer, the observed width will be greater than actual due to the angle and the estimated range will be low.

Regarding the assumption that Panthers used the scissors scopes on more than a rare occasion, the 1945 report to Gen. Eisenhower does not seem to mention German tank use of the scissors unless I missed the discussion. It would seem that German use of such a highly accurate rangefinder in Panther tanks would have been a major point to bring out.

A 3m x 3m target at 1000m with 2.5x magnification would appear to be 0.09" (0.23cm) to an observer (same size as a 0.09' object height held twelve inches, about 0.3m, in front of the eyes). Under the pressure of combat and in the rush to get in a killing hit, placing the gun sight cross hairs on the middle of an observed object that small could pose some problems for non-German guns during WW II.

With regard to Mr. Tittles' comment about the German practice of adding to the range estimate (Daniel should revise his earlier post on this issue as his explanation is not consistent with the Tiger and Panther Fibels), the gun sight would be set at the final adjusted estimated range and the effective cross-hairs would be placed at the bottom of the target.

If the estimated range was used as initially obtained or measured without adjustment, the hit percentage for a perfect range setting would be 50% since the mean trajectory would place the average shot on the bottom edge of the target. Half the shots would scatter off the mean point of impact.

The Germans countered the above problem by setting the gunsight on the target bottom but added to the range estimation so the shot would land about halfway up the target height. The procedure was to add one half the perceived height of the target in mils times 100m to the initial range estimate (Daniel in his earlier post multiplied 100m by the full perceived height, which places the shot at the top of the target).

When the target is at 500m, a 2m high target would appear to be 4 mils high, so half of 4 times 100m adds 200m to the initial range estimate. Final adjusted range estimate is 700m, which is what the Tiger Fibel shows (Elvira is 2m high in the Tiger Fibel example).

Lorrin

[rexford]

With regard to the three man range estimation procedure, the Tiger Fibel mentions it and has quite a bit of write-up. Perhaps it was limited to Tiger crews under ideal circumstances?

As was noted on the AFV News forum, when crews reach the front they sometimes experiment and find that what is in the manuals is not practicable, or there are better ways to do things.

Having more than one set of eyes certainly makes for a better estimate.

[ August 07, 2004, 09:18 AM: Message edited by: rexford ]

[Mr. Tittles]

The Zeiss prism binoculars of 1894 were the first commercially successful, the

first mass produced, and the first high quality binoculars. At the same time, Zeiss

offered 2 prism binoculars with objectives 12 inches apart (8 power,) and 16 inches

apart (10 power.) A hinge between the oculars allows them to fold in half, leading to

the generic term 'Scherenfernrohr' or scissors telescope. These were called by Zeiss,

"Relieffernrohre," and were not successful. The 8 x 20 model was offered from 1894

to 1906, and the 10 x 25 from 1895 to 1908 and through 1918 for military use. They

give spectacular views of terrestrial objects, greatly magnifying the perception of depth

in a scene and the appearance of modeled relief in an object. Here there is no

exaggerating the effect. They were used as rangefinders in both World Wars, by

several service branches of most of the participants in the conflict. Hand held

instruments were about 6 x 30, with objectives 18 inches apart, and a folding hinge to

reduce the length for transport. Tripod mounted instruments could have 50mm

objectives, for use at dawn and dusk. These were used by artillery forces to

approximately judge distances. The smaller sizes were needed for quick judgments

on shell bursts, when a large instrument or more complicated rangefinder could not

work quickly enough. These 'battery commander's rangefinders' can occasionally be

found at gun shows or military collectors' meetings, and there are a few optical repair

shops remaining that can correct their typical out of collimation condition.

[danielh]

Rexford,

I wrote in first post:

"A Tank 3m tall at 1000m will show as 3mils in the sight, correct "Nabelvisier" would be 1300m to hit him squarely in the middle. My "error-range" to still hit the tank with high probability is 800 - 1200m (In the first case a target 3m tall would show as nearly 4.5 mils, in the second at around 2 1/4 mils. One must have quite bad eyesight to make such an error when target is not in cover. First round hits will be the norm here"

I don't see any error in my initial calculation of the "Nabelvisier" (aiming at the bottom then adding range to hit in the middle). From Pantherfibel:

Their the formula is (pg 22 of Pantherfibel):

Estimated range + Targetheight in Strich ( or mils) x 100 = Nabelvisier for Armor piercing rounds.

For HE rounds: Estimated range + Targetheight/2 in Mils x 100 = Nabelvisier for Explosive shells. (pg. 21 Pantherfibel)

So my 1000m + 300m for a 3m tall tank (AP) is correct.

The Fibel also mentions that shot "climbs" only 1/2 Strich (or Mils) for every 100m range added on the ladder.

The figures for 800 + 1200m were estimates and the first one really being an error on my side, the second is only 10% off (i was in a hurry...,sorry)

In 1944 Tiger and Panther had 2.5 x and 5 x Magnification as you surely knows, so why do you calculate all in 2.5 Magnification ? (2.5 x was used to aquire target, 5 x was used to aim and determine range for "small" targets (= far away).

What do you think ?

Greets

Daniel