The lenses of the cameras are removed and then these are attached to telescopes to record images, video, still, or both.
In newer techniques, videos of very faint objects are taken for a couple of seconds and then all the frames of the video are "stacked" together to obtain a still image of respectable contrast.
A webcam is a video camera that feeds or streams its image in real time to or through a computer to a computer network.
When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks via systems such as the internet, and emailed as an attachment.
With very-low-light capability, a few specific models of webcams are very popular to photograph the night sky by astronomers and astro photographers.
Mostly, these are manual-focus cameras and contain an old CCD array instead of comparatively newer CMOS array.
One such function has the webcam act as a "magic mirror" to allow an online shopper to view a virtual item on themselves.
For a more complete list see Comparison of webcam software.
Special software can use the video stream from a webcam to assist or enhance a user's control of applications and games.
making them the lowest-cost form of videotelephony.
Despite the low cost, the resolution offered at present (2015) is rather impressive, with low-end webcams offering resolutions of 320×240, medium webcams offering 640×480 resolution, and high-end webcams offering 1280×720 (aka 720p) or even 1920×1080 (aka 1080p) resolution.