The lens is very modest, simply a double convex plastic lens with a focal length of 25 mm and an aperture of 1.5 mm (f/16). It is mounted in a metal housing with a T-thread on the outside that threads into the front of any CCD camera using a T-thread to hold its 1.25” or 2” nosepiece. To use the lens, simply remove the nosepiece from the camera and thread in the lens in its place. The flat surface of the lens should be outward (away from the CCD). Screw the lens into the camera about an eighth of an inch (3 mm), start the FOCUS MODE on the camera, and frame and focus on some convenient object. Focus by screwing the lens in or out. The depth of field is large, so objects in the room will easily be in focus. When focused, you can then GRAB an image, and adjust the background and range of the displayed result to optimize the image appearance. The lens forms an image that is good over an area about 7 mm in diameter, and deteriorates gradually outside of that.

If you set the camera/lens combination outside on the ground looking up, images of the constellations can be taken in exposures up to 10 seconds long before the earth’s rotation elongates the image. Stars down to 6th magnitude will be recorded.

This lens is not a substitute for a quality imaging lens. The images are only intended to be used for the purpose of testing the functions of the camera. The lens cannot be used to image a daylit scene – the camera will saturate in the shortest exposures. Also, do not try to image the sun during the day – the CCD may be damaged. The lens is intended for indoor use, for practice in using the camera before attempting imaging at the telescope.

The lens is provided as standard equipment with many SBIG CCD cameras, but is available as an option for other brands of cameras and those SBIG cameras not already provided with the lens.