I post this report since I was asked to write on the binocular by an
Italian binocular enthusiast, Mr. Paolo Morini. The article has
translated into Italian and is posted on http://www.binomania.it/binocoli/15x110/15x110.php
1 The casings and the mounting
2 The whole view
purchased this binocular in 2003 from a Japanese dealer, Kasai Trading, Tokyo, Japan,
for comet hunting (Photo 1, 2). The dealer called this binocular
gSuper-Bino 15x110h, and it costs about 300,000 Japanese Yen (some
1,900 Euro) at that time. The binocular disappeared from the Kasaifs
catalog at present, but they may deal in it. The original mane is
g110x15 Binocular PNB-1h, which is manufactured by Novosibirsk
Instrument-Making Plant (NIMP), Russia, from where you can buy it
directly. It is wonderful we gWestern peopleh can buy such attractive
gEastern productsh as they say in the Web Page; gHigh level of skill in
the optic producing, that was achieved in "cold war" years in USSR, now
serves for the production of first-class telescopesh. The manual states
that you can operate this binocular from plus 50 to minus 50 degrees
Celsius. Just only looking at this specification you know how sturdy
this binocular is! Under such high or low temperature your body is in
trouble before the binocular goes wrong.
15x110 model with different type of mounting that has a 70 degrees
maximum angle of elevation, PNB-2, is also
manufactured by NIMP, but I opted for the present model, PNB-1, because
it has a 90 degrees maximum angle of elevation; more suitable for
astronomical use. As I mention later, this choice may not be correct.
manual of this binocular is available via Internet. Basic optical
and mechanical features are displayed in this manual with the Tables
and the Figures, and please refer to it to read this article. The
instrumental description hereafter is based on the manual and the
catalogue of Kasai Trading issued in 2000.
manual Fig.1. Basic optical train
1, 2, 5, 9 -
lenses; 3, 4, 14 - prisms; 10 - neutral density filter;
11 - light
orange color filter; 12 - blue-green color filter; 13 - reticle.
weight and portability
of the binocular are shown in Table 1. The binocular casings with the
altazimth mounting are stored in a big wood box, and you have to carry
the tripod separately (Photo 3). You cannot detach the casings from the
mounting in the daily use. The total weight of the instrument with the
box is 37 kg. This is too heavy for me to carry for daily observing
session. I never carry the binocular with the box, instead I convey
bare binocular casings with the mounting (21 kg) from the storeroom to
my car leaving the wood box. Another model whose mounting has more
simple structure, PNB-2, weighs only 13 kg (the casings with the
mounting), and it would be preferable from the view point of carriage.
The strap of the tripod is convenient to carry, but you have to be
careful for the keen ferrules.
1 Dimensions and
the 15x110 binocular, PNB-1
of the values that I measured or based on the catalog of Kasai Trading
are different from those of the manual.
Maximum length: 385 (when hood are extended 458)
Maximum width: 570 (including handles)
||640 x 490 x 430
||930 to 1480
3 The instrument in the wood box and the tripod
4 Attachments. Some parts are not unwrapped.
following attachments are wrapped in paper and cotton (Photo 4). Such
non-plastic and classic wrapping is cozy!
kinds of filters:
Orange filter: for fogy weather, low illumination intensity of the
terrain, and low contrast of the objects.
Neutral filter: for bright dazzling light.
Blue-green filter: for protection against radiation of the laser.
these are of daytime use, and are unnecessary for astronomical purpose.
extra pair of desiccators:
mentioned in the next section, the desiccator with silica gel is
installed in each casing. These are replacement parts.
extra round level:
wonder if this replacement parts is necessary since the level would not
brush and napkins for optical cleaning:
brush with wood stem and classic napkins remind me of the good old days.
screwdriver, and pipe connection:
are wrapped in oilpaper with grease (Photo 5). The wrench is for the
desiccator, but I do not know what the pipe connection is for.
material is non-water proof (left in the wood box in Photo 3), and is
not effective for night time use when the dew falls .
online service manual includes 11 pages and some figures of the
original printed service manual that has 51 total pages. However, the
contents of the printed manual that are not displayed on the online one
are details of mechanics and parts replacement. The online manual is
enough for users.
5 Attachments wrapped in oilpaper
6 The binocular viewed from the underside. A pair of round parts is
the binocular is originally designed for air targets as well as the
ground ones, the eyepieces are inclined 30 degrees to the optical axes.
The finish of the casingsf surface looks somewhat rough, but it does
not affect practical use at all. The length of the casing is made
shorter by a prism system that once leads an optical path downward
before entering the eyepiece (Fig. 1 on the online manual). The
objective comprises of two separate lenses (Fig. 1 on the online
manual), and the first lens is an aspherical one. The eyepiece is 8
elements 5 groups with 90 degrees apparent field of view. Lenses are
multicoated, but the field of view looks yellowish in daytime due to
haze-cut coating: the binocular is made for the military purpose and is
haze-cut coated to improve S/N ratio especially during the twilight
use. For the night time use, i.e. astronomical purposes, you cannot
recognize yellowish color at all. Kasaifs catalog states the coating
reduces skyglow and boosts contrast in the field. The manual says light
transmission is 50% that is rather low value I feel, and the haze-cut
coating may be the cause of this.
reticule is inserted at the focal plane of the right optical tube
assembly (Fig. 1, 3 and 7 on the online manual), but you cannot see
during nighttime use. If you are eyeglasses wearers as I am, you can
view almost whole the field with your eyeglasses on, since the eye
relief is 15 mm; as this eye relief is the minimum value for eyeglasses
users, it slightly vignettes near the edge of the field (more than 90%
from the center of the field). Whether or not you are eyeglasses
wearers, you need to keep your face at the steady position relative to
the eyepieces to peer into the field. A good point of this instrument
is that you can do this easily employing a built-in headrest that is
extendable. The diopter setting ranges from minus 3 to 5.
pair of desiccators filled with silica gel is screwed into the
undersurface of the casings (Photo 6). You can check the condition of
silica gel through glass windows of the desiccators. You can remove the
desiccators with the wrench and dry silica gel using an oven if you
need. I have never done this since I bought this binocular (for more
than four years), because color of silica gel is kept bluish: I usually
store the casings with the mounting in a sealed big plastic bag with
about 300 g of silica gel to avoid mold growth (Japan is a humid
country) and this may be the cause of maintenance-free to date.
extendable tripod is solid and durable. There is a pivot with a
diameter of 22 mm on the tripod head that is inserted into the base of
the altazimth mount.
pair of built-in lens hoods is convenient, but it is sometimes hard to
draw it out (Photo 7). A single bolt works as a stopper and a guider,
and you slide the hood out along the rift in the hood. While you are
pulling the hood out, it is loose and you have the feel of an obstacle.
However, once extended, it is firmly fixed. When you retract the hood
you may have the feel of an obstruction again.
distance can be adjusted by turning a knob on the lower right side of
the right casing (a silver colored knob in Photo 1). It moves the right
side casing smoothly, and you can adjust interpupillary distance with
for both vertical and horizontal motion is changeable by using a knob
on the left side of the altitudinal axis and a one on the azimuthal
rubber shock-absorbers fixed inside of the left fork-arm (Photo 1 and
limit the vertical motion from minus 36 degrees to 90 degrees. The
binocular itself can be trained on 90 degrees in altitude, but you
look into eyepieces at this high altitude since your chin interferes
with the base plate of the mounting: you can observe up to some 80
and altitudinal limb are graduated up to 600 and 160 (100 to minus 60),
respectively. Since one division is 0.6 degrees they correspond to 360
degrees and 60 to minus 36 degrees, respectively. Using the verniers
the minimum readings are 0.2 divisions, i.e. 0.12 degrees. The scales
are clear and easy to read (Photo8, 9). You can rotate azimuthal limb
by loosing a knob beneath the mounting base and fix it at any azimuth;
i.e. you can set any azimuth to zero on the limb.
7 A lens hood viewed from the underside
8 Azimuthal limb with vernier. The
reading is 514.4, i.e. 308.64 degrees.
9 Altitudinal limb with vernier. The reading
is 15.4, i.e. 9.24 degrees.
daytime I aimed the binocular at a distant pylon. The image was brisk
and vivid with high contrast at the center of the field, but I did not
feel that the image was bright due to yellowish color of haze-cut
coating. The overall image was flat and distortion-free, and I did
distortion at a glance. With a careful look the image deteriorated near
the edge of the field. Then, I looked at the top of the distant pylon
and observed changes in the image. It began to deteriorate at about 70%
from the center of the field, and it got worse gradually toward the
edge. Over 90% from the center, it abruptly got worse. Even so, as I
mentioned before, I have an impression that the overall image was flat
enough, and the central image was superb. I have never experienced
false color with this binocular aiming even at bright objects.
image at the center of the field was perfect pinpoint with high
contrast. Distortion near the edge of the field stood out much more
than in daytime. Star image near the upper edge of the field distorts
concave upward, i.e. pincushion distortion. Even the first class
binocular, e.g. Nikon or Zeiss, reveals the same degree of distortion.
Considering the super wide field of this binocular, I must say the
optics is superb. With a magnification of 15 this binocular is not
suitable for detecting small and dark celestial objects, but I have
ever observed some of the10th magnitude galaxies. I read somewhere that
11th magnitude galaxies were observable with this binocular. The true
worth of this instrument lies in rich field with pinpoint star image
and high contrast: the Milky Way or open star clusters were impressive.
for astronomical use
Japan is humid dew or frost tend to condense on the objective lenses
even if you use build-in hoods. In addition to that the handles for
altitudinal axis are too short for smooth motion for comet hunting, and
a light shield for eyepieces is essential to concentrate on viewing
faint objects, e.g. comets and nebulae. To improve these points I
bought a pair of lens hoods, and made extended handles as well as the
light shield for eyepieces (Photo 10). The extended handles are made of
stainless steel pipes and styrene foam. The bases of the original
handles are enlarged by having the rubber band around it so that the
diameter of the bases fit the inner diameter of the pipe (swellings
at the bases of handles in Photo 1 and 6).
extended handles enable smooth sweeping of the sky with a light touch.
The light shield which is made of polyethylene sheet and flocked black
paper, can be attached to the eyepieces by a rubber band. Although the
binocular field is as wide as 6 degrees, since the eyepieces decline 30
degrees from the optical axis a finder scope is convenient accessory: I
attached the Rigel, QuikFinder. As I am eyeglasses wearer an eyepiece
without rubber protector damages the eyeglass lens. The rubber
protector is not equipped in the original eyepieces of the binocular,
and I attached rubber ring sheets to the eyepieces using double-sided
adhesive tape (ring-shaped black colored parts on eyepieces in Photo 1
and 10). Though this binocular is not my main instrument, I can enjoy
comfortable comet searching with these accessories.
10 Accessories for astronomical use: extended handles, hoods, light
shield for eyepieces,
rubber ring sheets on eyepieces and unit-power
binocular is designed uniquely and based on different philosophy from
gthe Westh; a prism system that is made the casings shorter, eyepieces
with super wide angle, the head rest, and the limbs that are easy to
read. On top of that sturdy structure and excellent optics made this
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