TAKAHASHI Guide-Only Telescope GT-40

This 40mm-diameter guide mirror is designed to minimize rattling and deflection, which are elements of guide errors.

Since autoguiders are now widely used, focusing is done only the first time the autoguider is used, so focusing is done by turning the objective lens barrel and fixing it with the lock ring, while the light-receiving part is fixed to the built-in 31.7 adapter. Using the GT-40 with a high-sensitivity autoguider such as the new α-SGR3 autoguider or a camera, you can capture stars up to about 9th magnitude. Since the guide star can be found in almost any direction, a guide mount is not necessary, thus ensuring rigidity and reducing the weight and simplicity of the photographic system. Note that a guide mount is required when using a low-sensitivity camera such as a web camera with the GT-40.