EMS Product Line | English.

EMS Product Line


EMS is the Erecting Mirror System invented by me,Tatsuro Matsumoto,Japan.
EMS offers non-reversed upright image with only two reflections.

There have been a lot of erecting prisms as the attachment of the astronomical telescops, but EMS is the only one that offer the right image with only two reflections and no edge line in the light path.
Another outstanding advantage is that it is used in the right angled viewing position and its unique lateral shift of the light path that can be symmetrically set up for the binocular use.

It is my pleasure to share my thrilled exprience of EMS with astro-friends.


EMS UM


Direct image of Astronomical Telescope


Reversed image by diagonal prism


Non-reversed upright image by EMS

The Sectional Sample of the Component of EMS

ADAPTERS
(click to enlarge)
The tapered flange(2″ diameter) on top of the EMS enables the adapters to be replaced by each other in a second with a set screw.
31.7AD is included in the EMS-UM/US, and 50.8AD with 2mm-profile 31.7AD in the EMS-UL.

More than 33years have past since the article of my homemade binoculars appeared in November,1982 issue of the Sky & Telescope magazine. Adding the period of my study for the optical system before the article, I have been studying the optical system for more than 36years.
I had succeeded in developing the EMS which offers non-reversed upright image at the right-angle viewing about 26 years ago, and have come to accept the order from amateurs.
The EMS has never betrayed users’ expectation, and every one of them admires the performance that never degrades the image quality.

EMS-ULTIMA

Evolution from aluminum to Silver


from left, EMS-US, UM, and UL

EMS-ULTIMA, equipped with enhanced silver coated mirrors, is now on sale. Now that EMS has achieved not only the diffraction limited resolution but also the practically total reflection of the incoming light, there will be no reason even for the most conservative users to dispense with EMS in their visual observation.
I believe it declares the advent of the new age of visual Telescopes.

The coating maker guarantees durabilities of the new silver coating as passing the tests of high-humidity and high-temprature, over 90 degrees centigrade with 90 percent humidity, soaking in the solt water, and etc.

More details

EMS for the single use;

Shown below are the prices for EMS series of the single use, as a diagonal mirrors with the non-reversed upright image at right angle viewing.  The binocular set is not a mere set of right and left handed EMS, but the special set that includes X-Y collimation device. For the prices of the binocular set, browse the following lists of “EMS for Binoculars”.

(Those who can make the efficient collimation devices by themselves can choose the left and right handed single-use EMS as the material of a binoscpe, as the cheapest choice; but I do not recommend it, becouse the following specialized binocular set will offer far better result.)

EMS-US 38,000yen

Eyepiece: 31.7mm
Light path: 122mm
Joint to scope: 50.8mm
Image circle (modest number with much margin): 26mm
lateral shift of the light axis: 26.9mm
Weight(with adaper): 395g

EMS-UM 54,000yen

Eyepiece: 31.7mm (option 50.8mm)
Light path: 122mm
Joint to scope: 50.8mm
48mm dust filter
Image circle (modest number with much margin): 30mm
lateral shift of the light axis: 26.9mm
Weight(with adaper): 420g

EMS-UL 63,800yen

Eyepiece: 50.8mm
Light path: 148mm
Joint to scope: 50.8mm
48mm dust filter
Image circle (modest number with much margin):38mm
lateral shift of the light axis: 35.4mm
Weight(with 50.8 sleeve): 500g
42mm or lager field stop of ocular will give no visible trouble. I am using 32mm by 80degrees ocular without any visible vignetting.

The above are the specs of the standard single types.

EMS for Binoculars

The EMS-SET for the binocuar use is equipped with the innovative X-Y image shifter on the right unit, that promises you the easiest collimation to merge the two images into one even at the highest magnifications.
So, “Binocular Set” is far from mere “a Rght and Left handed pair” of the EMS for the single use.

X-Y knobs and the image shift

At planning to build your own Bnoscope, your first task is to decide the “D” of your binoscope.
And then, you will have to choose the way of the IPD adjustment among the three choices below.
1: Fix the IPD to your own. (easiest and cheapest plan for the novice)
2: Introduce a sliding mechanism base for IPD adjustment. (DIY or commercial…)
3: Helicoid extension tubes in the EMS. (It will save your effort quite a lot.)
When you decide the above factors, I will advise you of the best choice of the EMS-SET for your plan.
You can calculate the required back-focus of the OTA to accept the light path of
the EMS by the “D”. How to calculate the approximate light path of the EMS is shown  in the linked file.
You will have to choose the OTA of enough back-focus or cut short  your OTA to extend the back-focus for your need.
(Back-focus is the tail of the light cone out of the OTA.)
EMS-UXL Pair
 

EMS is the ultimate solution to form a binoscope in combination with the refractive telescopes.

EMS offers;

  • Non-reversed upright image;
  • Symmetrical lateral shift of the light axis;
  • Normal stereoscopic vision;
  • Right angled viewing position;

With the least possible number ,two, of reflections by the high quality silver mirrors 3-dimensionally placed in the back-focus of a telescope.

X-Y image shifter

EMS-US (R+L pair) 98,000yen

Eyepiece: 31.7mm
Joint to scope: 50.8mm
Equipped X-Y image shifter

EMS-UM (R+L pair) 130,000yen

Eyepiece: 31.7mm (option 50.8mm)
Joint to scope: 50.8mm
48mm dust filter
Equipped X-Y image shifter

EMS-UL (R+L pair) 150,000yen

Eyepiece: 50.8mm
Joint to scope: 50.8mm
48mm dust filter
Equipped X-Y image shifter

Small Helicoid for IPD adjusting option: 40,000yen(pair price)

EMS-ULS (R+L pair) 160,000yen

Eyepiece: 50.8mm
Joint to scope: 65mmφ
48mm dust filter
Equipped X-Y image shifter

Small Helicoid for IPD adjusting option: 40,000yen(R&L pair)
Large Helicoid for IPD adjusting option: 60,000yen( ” pair)

EMS-UXL (R+L pair) 250,000yen

Eyepiece: 50.8mm
Joint to scope: 90mmφ
48mm dust filter
Equipped X-Y image shifter
Equipped Large Helicoid for IPD adjusting
Weight(with 50.8 sleeve): 860g X 2

EMS-UXL-Premium (R+L pair) 380,000yen

Eyepiece: 50.8mm
Joint to scope: 90mmφ
48mm dust filter
Equipped X-Y image shifter
Equipped Large Helicoid for IPD adjusting
Largest Silver mirror 60X120mm

left:EMS-UL, right: EMS-UXL
left:EMS-UL, right: EMS-UXL
EMS-UXL

EMS first mirror size

from left: US,UM,UL; US and UM are in common in the housing sizes.