Do you have a CCD camera without a mechanical shutter and would like to do dark frames without continually monitoring your equipment? Then the Astronomik Dark Filter could be right for you. 

This opaque substrate filter comes in 1.25-inch and 2-inch sizes, offered in a threaded filter cell. They are designed specifically to aid CCD cameras that do not have a mechanical shutter, such as the interline-CCD based cameras from Atik, Starlight Xpress, Imaging Source, and Lumenera. By installing this dark filter in your filter wheel, you can use it to effectively take a "dark frame" without physically capping off your telescope. While you might lose a position in your filter wheel, it's advantageous to those who image remotely. 

Astronomik Product Number: DARK-2