Product Description
This is a very nice alignment telescope or collimator. It is manufactured by the German company Moller / Wedel (with an umlaut over the 'o' in Moller). There are three components to this telescope. The first is the objective and tube assembly. The objective has a 300 mm focal length and is 50 mm in diameter - quite large. The tube is highly polished steel and held to extremely tight tolerances with regard to optic axis / parallel to tube diameter. Mechanical and optical axes on a 300 mm focal length objective differ by only plus or minus 0.3 microns The reticle is critically adjusted to the infinity plane using monochromatic light at a wavelength of 546 nm.
This telescope has the simple reticle holder installed. The holder is fitted with a plain single crossline glass reticle. The crossline is positive (dark cross on transparent substrate). I am unsure of the catalog number of the reticle.
On the end of the reticle holder is another thread that will accept one of three different eyepieces or one of at least two different lamphouses. A lamphouse instead of an ocular would convert the assembly into a collimator, but the reticle would probably be replaced with a negative type (bright crossline). This instrument is fitted with the lowest magnification ocular, with a focal length 25 mm. (Other oculars are available from Moller Wedel with focal lengths of 10 mm and 14.7 mm). Net magnification of the telescope is 12x. Image is inverted.
This is a currently manufactured instrument from Moller Wedel, and the catalog description would be FG 300 / 65 / 25. The 'F' denotes telescope system, the 'G' denotes straight view (as opposed to inclined or right-angle). The 300 is the focal length, and the 65 denotes the diameter of the steel tube. Lastly, the 25 is the focal length of the ocular installed. These are among the very finest instruments made, and this one is in fantastic condition. Asking price is a small fraction of current list price. This instrument is in stellar condition. The only evidence of use I could discern are some bright spots on the knurling of the eyepiece diopter adjustment ring and a few bright spots on the edges of the step down flange of the objective tube. The objective itself appears flawless. This is a spectacular piece of glass.
Location MB 26.1
Photoset 207