Matsumoto EMS Erecting Mirror Diagonals Sytem-Single Use JAPAN

!!ATTENTION !!

It can only be obtained via trade.

EMS-UMA/UL is Erecting Mirror System-Single use is not EMS-SET for binocular use a Right and Left handed pair.

I received 58 requests to buy Matsumoto EMS and you should be know what's sell does not actually occur only trade.

It's a very high quality diagonal that uses silver coated mirrors to give you an image that is correct left-right and up-down.

It's made in Japan by Mr. Matsumoto. Now it's no longer available.

[Important Notice] Passing of  an Owner, Matsumoto Tatsuro. After a period of medical treatment for an illness,
he passed away on December 8, (2025), at the age of 74.


The Matsumoto image erecting diagonal uses just two mirrors to create a non-reversed upright image with only two reflections and no edge line in the path. As a result, the Matsumoto diagonal produces an image with none of the ghosting or spiking present in Amici or Schmidt image erecting diagonals. A durable protected silver coating is used for high reflectivity and less scatter than dielectric coatings. The EMS-UMA is meant for single eyepiece viewing (some Matsumoto diagonals are designed to be used in binocular telescopes). This unit has a 2" nosepiece, and a 1.25" eyepiece holder with a 2" eyepiece cap and a 1.25" eyepeice plug. 

• Matsumoto 90º EMS-UMA 1.25"  (Correct Image Erecting Mirror Sytem-Single Use)
• Matsumoto 90º EMS-UL 2"/1.25" (Correct Image Erecting Mirror Sytem-Single Use)

The ideal 90° anti-aircraft mirror/The ultimate erecting mirror

EMS (Erecting Mirror System) is an astronomical telescope attachment developed by me (Tatsuro Matsumoto).   EMS is the ideal 90° anti-air option, as it requires only two mirror reflections to obtain an upright image without image quality degradation.   EMS was developed in 1989 and patented in 1994. Since then, various improvements have been repeated to reach the current completed form. (Currently patent open)

The ideal 90° anti-aircraft mirror/The ultimate erecting mirror

EMS (Erecting Mirror System) is an astronomical telescope attachment developed by me (Tatsuro Matsumoto).

EMS is the ideal 90° anti-air option, as it requires only two mirror reflections to obtain an upright image without image quality degradation.

EMS was developed in 1989 and patented in 1994. Since then, various improvements have been repeated to reach the current completed form.

It released the first EMS, Erecting Mirror System, in 1989, and it was patented in Japan in 1994.

EMS is the innovative two-reflections’ erecting system that offers non-reversed upright image at the right angle viewing position, with no unwelcome deterioration of the image. Since then, EMS has evolved into the current products.

EMS is also the most effective option for achieving BINO conversion with refractor telescopes.

Ideally, an astronomical telescope should have nothing between the objective lens and the eyepiece lens. It has been proven in various fields, such as self-made examples of small inverse binoculars.

Spatially arranging the minimum constituent elements based on specific rules, with two reflections without a prism.

① Erect image
② Optical axis shift (corresponding to interpupillary distance)
③ Normal stereoscopic vision
④ 90 degrees anti-air

EMS is an erecting optical system that satisfies at least four of these conditions at the same time.

EMS offers:

• Non-reversed upright image;

• Symmetrical lateral shift of the light axis;

• Normal stereoscopic vision;

• Right angled viewing position; 

EMS-UMA

Eyepiece: 31.7mm
Light path: 122mm
Joint to scope: 50.8mm
The image circle (modest number with much margin): 30mm
lateral shift of the light axis: 26.9mm
Weight(with adapter): 395g

EMS-UL

Eyepiece: 50.8mm and 31.7mm
Light path: 148mm
Joint to scope: 50.8mm
48mm dust filter
The image circle (modest number with much margin):38mm
lateral shift of the light axis: 35.4mm
Weight(with 50.8 sleeve): 500g
42mm or larger field stop of ocular will give no visible trouble. I am using 32mm by 80degrees ocular without any visible vignetting.

It's in as-new condition and a nice padded bag it's been kept in :)

Looking to trade for some of these items

• Masuyama   50mm 53°
• Masuyama   80mm 34°
• Masuyama   80mm 52°
• Masuyama 100mm 46°
• Kokusai Kohki Masuyama 3 inch (76.2mm) barrel size 80mm 52°
• Siebert Optics 3 inch (76.2mm) barrel size 40-80mm

Asking $999.99 includes shipping

Message me for further discussion and questions on e-mail