Deluxe Class Solid Brass Captain's Spyglass Telescope 15" w/ Rosewood Box

The basic function of antique brass telescopes is to gather light to create a detailed image. The larger the gathering lens, the more light that is collected, and the more defined the image. From this basic light gathering premise, there are two typical solid brass telescope models. Refracting brass telescopes use a large objective lens to collect and bend light, while the reflecting telescope uses a large concave mirror to achieve this. In the refracting telescope, as the light passes through the glass lens, it is bent inwards at all directions so that at some point in the barrel of the telescope, the focal point, all the points of light converge. As light does not just stop, it continues to spread out again after this point, however, the eyepiece lens gathers this focused light and sends it to your eye. With the primary lens bending light inwards the resulting image appears inverted, though a second set of lenses in the eyepiece right the image before it reaches you. One of the problems with this type of solid brass telescope is that different colors of light have different wavelengths and are bent different amounts by a single lens. The result is that the image can appear blurred or fuzzy around the edges as the light cannot come back into complete focus. Alleviating this issue, the reflecting telescope was invented. In a reflecting solid brass telescope the use of mirrors take the place of glass lenses. A primary mirror is curved at just the right angle to send the light to a tilted secondary mirror, which in turn focuses the light onto the eyepiece.