The Sirius IR Block Filter 2 inch blocks infrared light from reaching the sensor of your CCD or CMOS camera or your expensive H-alpha filter. When imaging, the addition of this simple and inexpensive accessory will result in sharper images, and when doing solar work, the IR Block Filter will your protect H-alpha filter from the damaging effects of infrared radiation.
Infrared or IR light is invisible to the human eye, and so even though most telescopes are not designed to focus IR light, it does not matter when you are using your telescope visually. However, when you add a camera to the mix, its a whole other story! Unlike the human eye, a silicon sensor is very sensitive to light in the infrared portion of the spectrum, and that is a problem because infrared images are blurry as all get out. That means your nice, sharp visual light image is degraded by the addition of the infrared layer. This problem can easily be solved by blocking the infrared, and the Sirius IR Block filter 2 inch will do just that.
The Sirius IR Block filter is housed in a 2″ cell, and has internal threads so that you can stack filters together. The filter comes with a protective plastic case.