Product Description
The lens elements of this massive optical assembly appear to be made of zinc selenide - they are somewhat transmissive in the visible, strongly orange tinted. They are also coated, but no optimal wavelength range is specified. ZnSe is fairly uniformly transmissive from about 0.6 microns to around 16 microns. Because of the high index of refraction coatings are used to optimize transmission in the wavelwngth range of interest.
This lens assembly is in a massive rigid mount without aperture or focus ability.
The front element (larger element) has a clear aperture of 2.625 inches, the rear element 2.08 inches. The mounting flange has a diameter of 6.625 inches and the mount length is 3.965 inches. The rear focal plane (infinity collimator using visible light) is approximately 24mm behind the rear element. The front focal plane (same setup) lies approximately 75mm in front of the element.
This system has no engraving as to manufacturer, however there are some numbers printed on the mounting cell. The first number is 226814G1, and underneath that, the serial number SN001. Condition of the external surfaces is very good - I could see a couple of very slight blemishes on the front element coating near the margin, but did not attempt to clean them.
Photo set 1519