Variable Barlow Adapter for a Webcam
Changing the distance of an eyepiece or other sensor such as a webcam or DSLR changes the effective power (magnification) Andy Barber has made such a set-up for planetary imaging with a Phillips Toucam.
The effective focal length achieved will depend on the Barlow used and the distance from the Barlow to the imaging surface. These are calculated and displayed in the following graph.
Andy’s set-up including the box that protects the Laptop from the damp.
Image of Jupiter taken with a variable Barlow and Philips ToUcam in 2010