After hours at the eyepiece, you finally get to view the fruits of your astrophotography labors. The stars in the center of the field pop like brilliant precise points of light. But as you survey the image, you notice the stars at the edge have taken on an unnatural comet-like shape. Your long night has been marred by coma. Coma is a common plague of the Newtonian reflector design, and its annoying presence at the outskirts of an image can be a bane for astronomers of all levels.
Explore Scientific's HR Variable Coma Corrector is a high-performance optical corrector designed by world famous optical designer Harrie Rutten, and it will help you minimize or even eliminate image aberrations caused by this off-axis optical phenomenon even in fast Newtonians. This 2-inch coma corrector with is EMC Coated to reduce internal reflections and its spacer with markings allow you to use the device on almost any Newtonian telescope with a parabolic primary mirror, even fast Newtonians such as the BRESSER N20839 f/3.9 Photo Newtonian. Tightly secured by three thumbscrews, this accessory comes with two adapters (.75" and 1") to secure to your T adapter and a protective cap.