Made using Ohara FPL-53 optical glass, the William Optics 61 mm Guide Star delivers superb optical performance for high contrast images that are all but completely free of false color. Its 360 mm focal length is ideal for use with telescopes that have focal lengths between 700 mm and 1200 mm. In addition, optional accessories are available to make the GS61 suitable for astrophotography applications.

Focus is optimized by adjusting the dew shield, and set via the locking ring. Using the newly designed extension tube included with the GS61 enables ideal focus to be achieved in only a few steps. CNC-machined optical tube rings and bracket with Vixen-style sliding base for compatibility with all William Optics saddle handle bars are also included. Lastly, optional accessories such as the WO Flat 61A can be added for excellent flat field images, enhancing the GS61's astrophotography capabilities.