Hans Seeger, Militaerische Fernglaeser und Fernrohre, 2.6, pages 185-200
Scissor Telescopes. Hans Seeger, Hamburg and Alfred Koenig, Herborn
[page 185] Observation from behind cover or protected from enemy
sight has always been a necessity in the military. The oldest device
for this purpose is the Polemoscope, a stand with two parallel pairs of
mirrors at 45 degrees to the tube. 'Hevelius maintains that he had
invented this Polemoscope in 1637' (Pisko 1869, where on page 51 is a
picture of such an instrument. See bibliography.)
In the ‘Stationary War’ [Stellungskrieg] of the first World War, the
rampart mirror, known for centuries, was revived. We will mention the
simple monocular ‘ditch mirror’, built with and without magnification,
only in passing. Hanns Guenther gives a very good synopsis of trench
periscopes in 'The War - Illustrated Chronicle of the War 1914/15', 3rd
volume (Stuttgart: Franckh’sche Verlagshandlung, 1915). Bombastically
and with the arrogance so common in wartime, it says, after having
talked about the primitive rampart mirror at the English front:
'The German technique, with a superiority that is shown in small
details, was not satisfied with a simple imitation of the rampart
mirror; but, using modern methods, created higher quality instruments,
including the trench periscope introduced by the Austro-Hungarian army
administration, which was constructed by the most important optical firm
in Austria: C.Reichert in Vienna.' [page 186] The pictures from this
work are shown in fig. 103.
At first we will describe a German made supplement to the telescope;
it adds to the field glass the functions of a periscope: namely
observation with a magnified view, from behind cover. Schwarte reports
in 1920, among other things, about this model: 'Half scissors for one
eyed use were frequently used; field glasses were also made usable for
trench observation by adding a set of mirrors to one objective, to raise
the point of view by 360mm.'
The unmistakable scissor telescopes, which in England are often
graphically called 'donkey’s ears', are well-known and belong to these
military models. The advantages are obvious: One can observe from
behind cover, that is to say over a shelter, without being visible or
exposed to fire. Furthermore it is possible to observe from behind a
narrow obstacle (a tree for example), while standing up or lying down,
when the arms of the ‘scissor’ are completely spread apart. [page 188]
In this observation position, because of the wide-spread objectives, an
especially ‘plastic’ image is produced, with a degree of depth in the
image that allows one to distinguish the different distances of various
objects, which could not otherwise be observed. Fig. 105 demonstrates
the different uses of these glasses.
The development of the scissor telescope by Zeiss, Jena happened
simultaneously with the first manufacture of prism binoculars during
1893-94. Both of these forms of the prism binocular were protected by
the same patent (Patent no. 77086 of July 9, 1893). The first models
were smaller and known as ‘relief telescopes’. These have the
appearance of civilian instruments in their inscriptions, their looks
and their cases (see fig. 73). They could be bought on the open market
by non-military persons; but only with military usage did the advantages
of their design become fully clear. There are known examples of early
ten power ‘relief telescopes’ with reticles, so they were produced for
military usage.
Pronouncements about whether the larger models of the early Zeiss
scissor telescopes were ever produced for civilian use or even intended
for it, would be pure speculation, and this question remains unanswered.
See fig. 73b and its text.
The predecessors of the scissor telescopes were at the time called
‘relief telescopes’. They had magnification of 8 or 10 power, two
choices which proved themselves and were used again in the later
military models.
Note: In the Optical Museum of Jena, there is a 6 power relief
telescope; this version was probably produced in a small production run
until circa 1895.
In fig. 106 is the successor of the 10 power ‘relief telescope’ (see
fig. 73a), which was named the 'Teleplast'* (*This name has caused much
confusion and mistaken associations between early Zeiss models. At
first the name ‘Teleplast’ was used for civilian field glasses with
Sprenger prisms, see fig. 64 in 'Feldstecher'. These models have no
resemblance to the ‘mini-scissor telescopes’,which were at first called
‘relief telescopes’. The later 10 power small scissor telescope model,
from the first decade of the 20th century, was named the ‘Teleplast’,
which, as mentioned, was used for another model as well). At first
glance, this model is recognizable as a military field glass. The
author knows of no eight power models in this design, that is, with gray
painted finish; and there probably was no corresponding Zeiss 6 power
model for military use.
Zeiss developed three larger scissor telescopes circa 1905, which
were exclusively for military use, and which are shown from the catalogs
in fig. 107. We can easily imagine that at Zeiss, the strategy was to
use the remaining time until 1908, before the patent expired, to be a
step ahead of the competitors, with several variations of their models.
The basis for all later, larger scissor telescope models, are these
three models: the Hypoplast, the army scissor telescope, and the scissor
telescope for field artillery
The specifications for these models were probably identical (10 x
40). The scissor telescope for field artillery is known to have
contained traditional Porro-I prisms which were cemented together, see
fig. 107, left. The other two models probably have the same prism,
indicated by the similar form of the prism housing. [page 190] This
design did not become obsolete, it is shown in figures 109 and 123. All
three models have a reticle which is not illuminated.
The scissor telescope for field artillery and the army scissor
telescope are similar to the earlier civilian (?) scissor telescope
model by Zeiss. Shown in fig. 73b is a Zeiss export model, and the
first scissor telescopes made in Jena must have been of the same
construction, or at least very similar. All of these models, as well as
the first relief telescopes, have the advantage of permitting
observation at two positions of the telescope arms: parallel and
upright, or out spread. The directions for the scissor telescope for
field artillery explain the advantages:
'Preliminary remark: in one position for use of the S.-F. for field
artillery...the observer views from behind an obstacle (for example, a
trench); and in the other position...around an obstacle (for example, a
tree); consequently he is protected, in either case. The S.-F. for
field artillery, when used with out-spread arms, provides a much higher
plasticity of the image, and the objects consequently appear behind each
other, not next to each other, and strongly distinct from the
background, (corresponding to their natural position) even at large
distances.
The use of the S.-F. for field artillery will consequently be most
frequent with out-spread arms.'
But at the front lines of W.W. I, the reality was different, see
also the remarks for S.F. 17.
[page 191] The Hypoplast purposely abandoned the advantages of
maximum enhanced depth of the image. The Hypoplast has only one ‘work-
position’ of the arms, which can be seen in figures 107 and 108. The
Hypoplast uses a configuration that is in between the two characteristic
positions of a traditional scissor telescope, the first position for
observation from behind cover, and the second for an enhanced depth to
the image (which results from the larger ‘basis’ or wider distance
separating the objectives compared to the interpupillary distance (see
‘Feldstecher’, page 131). For the Hypoplast, this distance is not as
large as for a scissor telescope with fully outspread arms, and its name
indicates this as well: Hypo means lesser or diminished.
In 1911 the old Hypoplast was revived in a new form as 'Hypoplast
1911', with a 10 x 50 configuration. There is only one working position
of the arms, similar to the original Hypoplast, see fig. 108. No
survivor can be shown for this model, and it probably was built in very
small quantities. This note from a Zeiss magazine probably was not
confirmed by reality: [page 192] 'It is superior to the scissor
telescope by its greater simplicity of use. This is achieved by the
fact that the telescope arms have a fixed position to each other, which
results in the observer remaining behind cover, and in addition provides
images with higher plasticity. By the simple turning of a screw, the
interpupillary distance of the observer is adjusted to; while all other
scissor telescopes require several manipulations. This version is
protected by a Zeiss patent. In the right ocular there is a reticle,
which is made with any desired partition.'
The optical construction of an early scissor telescope is visible in
fig. 109. It can be seen that both prism configurations are derived
from the Porro I and Porro II systems. The prisms in American scissor
telescopes, which in the U.S.A are called battery commander’s
telescopes, are described by Jacobs (1943, page 219), and shown in fig.
109.
Some scissor telescopes use roof prisms, as do some hand held
telescopes. Fig. 109 shows the prism of an S.F. 14 in its mounting.
The leading optical firms in Germany produced scissor telescopes
during W.W. I, and probably were already making them in the years before
1914. The starting signal for most of the firms would have been the
expiration of the Zeiss patent in 1908. In 1893, Zeiss patented the
prism binocular with increased distance between objectives, and also
protected the design of the scissor telescope in monocular and binocular
forms.
As with some military glasses, some scissor telescopes signed by a
company were of different manufacture. We shall not dwell on the small
differences betweem scissor telescopes with the same name, but by
different producers.
A model that is not rare even today, is the S.F. 09 (S.F. =
Scherenfernrohr [scissor telescope]). From the number 09, it can be
deduced that this widely used standard model was introduced in 1909 for
the use of the German military. Fig. 110 shows this 10 x 45 model with
bearing circle. In fig. 115, the typical reticle for the S.F. 09 is
shown, which was not yet illuminated. (Nearly all later S.F.s with
reticle have illumination for the reticle). In fig. 110, the
transportation containers for the cavalry can be seen.
[page 193] The S.F. 09 has excellent optics, and it is therefore
not surprising that this model, along with other optics of W.W.I, was
still used by the military during W.W.II. An interesting example of
this is shown in fig. 110. This S.F. 09 was officially rebuilt and re-
engraved, and the grey blue color of W.W.I was painted over with the RAL
regulation Army grey-green. Also, the engraved artillery symbol (the
grenade symbol, a cannon ball with flame), was painted over. The S.F.
received different oculars, a [Gitterplatte, type of reticle with a
grid], and a built-in illumination window for the reticle. The new
engraving: 'Gi H/6400' (=Gitterplatte) indicates this reticle.
Shortly before and during W.W. I, other scissor telescopes were
built. In 1914, before the war, the S.F. 14 was built by Zeiss for the
foot artillery. Its specifications, 10 power and 50 mm objective, were
kept for most of the later models until the end of W.W. II, but the
short design was not retained. The distance from the middle of the
ocular to the middle of the objective is only 220 mm. in the S.F. 14 for
foot artillery. The advantages of this short construction are less
weight and a handier form, but these do not make up for the disadvantage
of an insufficient capacity for the observer to maintain cover. Fig.
112 shows an example of this rather rare model.
[page 194] Because of the disadvantages of the foot artillery model,
shortly after the start of the war (1914), the S.F. 14 with elongated
arms was introduced in Jena. It resembles its predecessor in the
markings and optical specifications, but the arms are elongated by
110mm.
Goerz, Berlin, also developed an S.F., which distinguished itself
from the Zeiss models by a characteristic form. The specifications were
also 10 x 50, see fig. 113. Fig 115 shows the reticle of this S.F.
Another producer of this variety of S.F. is the company A.-G. Hahn,
Cassel.
In the course of the first world war, from about 1916 on, a larger
version of the Goerz S.F. was built, the 'M 16' (M= model?), see fig.
113. The M 16 was produced in low numbers, with specifications of 15 x
60. In Jena, Zeiss made a 15 x 60 S.F., produced in a small production
run (f.o.v. 58m/1000m).
Zeiss modified its own S.F. 14 (with elongated arms) during the
first World War. Using the same optics, the telescope bearing and the
height device were changed, and thus the Zeiss S.F. 14 Z was born, which
in nearly unchanged form was made until the end of the second World War
by the leading German optical firms.
Even in the modern German military, this model was used; because
S.F. 14 Z Gi examples, with the color of paint used by the Bundeswehr,
and with coated optics are known. [page 195] It is not clear, when and
how these S.F., which were the property of the Wehrmacht, entered the
Bundeswehr, and where they were overhauled. In the beginning of the
Bundeswehr, it probably wasn’t S.F.14 Zs that were used, but rather the
American BC65 (see fig. 123). But this battery commander’s telescope did
not meet the expectations of the German military. Many of them were
modified by Zeiss in Oberkochen, so that they fulfilled minimum optical
requirements. Understandably, this procedure was not publicized (from
the communication of a Zeiss colleague).
A slightly modified S.F. 14 Z Gi was built in the second World War
for use in tanks. It had a small, removable forehead support and did
not have a spirit level for measuring the angle of the terrain. In the
interior of the tank, there were movable arms with pegs to install the
scissor telescope (we will not describe the successor to this
instrument, the RWDF 10 x 50 developed by Zeiss Oberkochen in 1956/58
and delivered after about 1960.)
With a relatively small field of view, (87 m/1000m), an S.F. 14 Z
delivered a precise and sharp image. One can recognize details and is
given the impression of looking through a higher power telescope. This
excellent optical quality explains their frequent use, especially during
the second World War. Therefore the following official communication
from the war years is astonishing, and possibly the high command of the
Army may have been afraid that the German soldiers had not made
sufficient use of their optics at night during the war.
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)'
A major problem for the S.F. 14, as for all scissor telescopes, was
that of collimation: the length of the arms and the fact that they are
freely movable (as the long arms of a lever), permits an exertion of
very little force to slightly tilt the arms and therefore move the
optical axes from parallel to each other. Because of the relatively
high magnification, a fused image, (with no double image), can only be
seen after a precise collimation. The rough treatment which a scissor
telescope has to endure during its ‘life’ means that a perfectly
adjusted specimen is rather rare. Those which are aligned in both
positions of use, (with upright arms and with outstretched arms), are
indeed rarities. (The alignment of an S.F. is an unloved and thankless
task even for the experts.)
The S.F.s of the first World War, along with those of the Imperial
Army, and those which were built at the beginning of the second World
War, made use of brass and show careful workmanship. Specimens from
circa 1944 are ‘simpler’, but retain the same optical quality.
All military S.Fs were painted, and during W.W. I, field grey was
the only color used. In the mid-twenties, new instruments for the
Reichswehr were delivered with a camouflage paint (official name:
multicolor paint); but this was not extended to all older instruments.
In the Army instruction pamphlet of the Reichs ministry of March 1927 it
says:
'Painting of the scissor telescopes: A replacement by the troops of
the field grey paint with the multicolor paint on the existing scissor
telescopes is not intended. The multicolor paint is only intended for
the scissor telescopes from the new production.... S.F. 14 Z on hand
will keep the field-grey paint.'
A short time later, the perceived need for camouflage paint on the
existing supplies must have become greater, and the ‘nit picking’
attitude was officially abandoned. It says in the Army instruction
paper of August 1928 under 'paint for observation and measuring
instruments': 'The troops can acquire the special paints for the
observation and measuring instrument on the open market.' Obviously the
troops were able to individualize ‘their’ instruments from that point.
Today we find old German scissor telescopes in grey, grey-green, olive
green and so on. In addition to the Reichswehr, the Wehrmacht must have
used the tricolor camouflage paint. During the second World War, blue-
grey, green-grey, sand, and clay colored paints were frequently used.
The S.F.s that were produced at the end of the war were without the red
primer undercoat.
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.
...
Dozymetry