Binoculars Alhambra 8x30 Enosa (Madrid), Enosa Trophy, 1976
Binoculars 8x30 Alhambra model, produced by Enosa (National Optical Company, S.A.) in Madrid under LTIEMA license (Laboratory and Research Workshop of the Naval General Staff).
The conditions are exceptional and complete.
NATIONAL OPTIC COMPANY, S.A. (ENOSA)
José María Otero Navascués also created the Empresa Nacional de Óptica, S.A. (ENOSA) whose mission would be to manufacture the LYTIEMA prototypes. At the same time he sought collaboration with the company ZEISS of Oberkochen with the purpose of creating a synergy between ZEISS, LYTIEMA and ENOSA to extend its products outside of Spain. He obtained a contract between ENOSA and ZEISS Oberkochen and as a result of this, a team of German experts consisting of five engineers and a carving master moved from Oberkochen to Madrid to organize the work in the different sections and equip them with the necessary machines.
The National Institute of Industry (INI) took charge of the construction and start-up costs of the factory.
The German engineers and the workshop master settled in the LYTIEMA, until the ENOSA works were completed. Among them were Mr. Müller, an engineer specializing in rangefinders, and Mr. Stolenberg, an optics workshop teacher.
Otero Navascués' idea was more ambitious: to convert ENOSA into a subsidiary of ZEISS of Oberkochen. The Technical and Commercial Management would be shared between the two entities. ENOSA would manufacture all the devices ordered from Zeiss. These devices would carry the ENOSA brand adding that they were a Zeiss system. ENOSA would have autonomy to design, calculate, project and manufacture its own devices. Zeiss reserved the manufacture of glasses.
But relations between ENOSA and ZEISS broke down. The Germans left and ENOSA began manufacturing binoculars and sextants with LYTIEMA plans. ENOSA built several models of binoculars, a “Cadete” model microscope, an aneroid barometer and various teaching materials such as binocular magnifying glasses, microscopes and projectors. ENOSA paid royalties to LYTIEMA for manufacturing its prototypes.
ENOSA manufactured, under license from LYTIEMA, the following binoculars:
Minar 4X15, with Sprenger-Leman prisms and central focus.
Medimar 6x30
Medigón 8x30
Alhambra 8x30, with Porro prisms, single-cap housing and central focus
Luremar 7x50, with Porro prisms, single-cap housing and individual focus
These binoculars are an example of a product well manufactured by ENOSA down to the smallest details. The mechanical quality is extraordinary and optically they are comparable with the best binoculars of American or Japanese origin.
An example of its construction quality is its collimation system using eccentric washers: in most models, once the eccentrics are adjusted, they are immobilized by pressure from a third fixing washer that is threaded on the edge of the tube. But it usually happens that when tightening this washer, the system of the two eccentrics is dragged with it, thus falsifying the collimation. In the LUREMAR from ENOSA, the pressure from the fixing washer is transmitted to the eccentrics through another flat washer that is anchored in the tube and cannot rotate. In this way, the rotation of the fixing washer does not influence the position of the eccentrics.
The apparent field of view is estimated at just over 50º and the image is clear and contrasted to the edge. Compared to a Carl Zeiss Jena Jenoptem 7x50W with multi-layer anti-reflective coating, the ENOSA's apparent field and sharpness are similar, although the contrast is somewhat lower. In daytime observations under backlit conditions, diffuse light is not seen in the darkest areas. In nighttime observations with intense lights (the moon, streetlights, etc.), weak reflected images are seen, symmetrically located with respect to the center of the field. Overall, optical performance is very good to excellent.
Another characteristic is that the images are free of distortion, that is, the straight lines of the object are reproduced in the image as straight lines. This is a design feature of older binoculars. Currently, optics are designed with some corset distortion to avoid the so-called “balloon effect” when observing a panorama by panning with the binoculars.
ENOSA also disappeared, although in this case the INI made money from the great revaluation of the land that the factory occupied (several hectares) in the Pinar de Chamartín de la Rosa, road from Fuencarral to Hortaleza, (today Avenida de San Luís).
Taken from:
https://hispanismo.org/ciencia/20303-tecnologia-optica-espanola.html