A telescope consists of two parts. Part One: A lenses or mirror that forms an image. Part Two: A magnifying lens called an eyepiece.
A decade ago, a strange realization wondered into my brain that a camera lens is the front half of a telescope. The camera lens forms the image at the film plane.
Only question left to answer was "Can I build an adapter to mount eyepiece on to the camera lens?". So, I grab a rear lens cap. I cut the cap so only the ring part was left. I went to the local hardware store and brought a 1 1/2" male to male coupler and thumb screw. I reamed the inside of the coupler just enough to super glue the rear lens cap in to it. I then grab a scrap piece of oak and make a circle that would into the coupler. I cut a 1.25" hole in the center of the circle for my eyepieces. I tapped a hole for the thumb screw and painted the whole thing flat black. It work and for less than 2 dollars.
The camera lens that I was using is 500mm f/6.5 T-mount lens with a Canon FD adaptor. I discover that Edmund Scientific had stuff for T-mount equipment. So I order an 25mm extension tube (Stock No. NT52-295) and an eyepiece holder (Stock No. NT52-303). This way I eliminated the the FD adapter and made it look professional.
All in all, it turn out to be a great little refractor. I use it alot for quick observations or as a finder scope. I usually mount it on my binocular parallelogram mount. It is great at my club star parties.
From left to right: the camera lens, the 25mm extension tube, the eyepiece adaptor, and finally the eyepiece.
There it is mount mount on my Light Duty Parallelogram Binocular Mount.
Over a decade ago, I started to see low power wide field of view
telescopes build by fellow ATMer's that used the lens from an old copier
machine as the objective lens. Hence, the name for scope became known
as a "CopyScope".