COPIER LENS (surplus lens) TELESCOPE
In order to construct a Copier Lens Telescope for about $50.00, you will need the following:
30-45 minutes of free time
1" and 2" masking tape
2 1/2" diameter PVC--7" long (5 1/2" if you plan to use a "Star Diagonal")
* 1 - Bausch & Lomb main objective lens,
8 1/4" (focal length) at f 4.5 or...
f 4.5 Taylor-Hobson or Rank Precision Optics lenses
* 1 - 25 mm Kellner eyepiece
2" to 1" PVC bushing for focuser
Contact paper / trim, if desired
Wrap the base of the main objective Bausch & Lomb lens with the 1" masking tape until it fits tightly into the PVC tube, making sure that it is snug and secure. The thickness of PVC pipe will vary, so the number of rounds of tape that you will use will vary. Keep the tape tight and smooth. Wrap more and cut back, rather than wrapping too little and having to add more tape. When you feel that you have enough (test by trying to fit the end of the taped end into the tube--if it goes in easily, you have too little tape...if it won't go in, you have too much) , cut the tape in a deep diagonal with the long point up next to the flange. The idea is to have more tape tapered toward the lens so that the farther in you screw the eyepiece holder, the tighter it gets. You want the main objective to tighten very snugly into place as you use a screwing motion to fit it into the PVC pipe.
Wrap the 2" tape around the PVC bushing behind the flange. Try not to get wrinkles...keep it smooth and tight. Wrap until the bushing fits into the main tube...not too snugly. Test by angling the masking tape up toward the flange, and use the masking tape overhang to fit into the tube. You may want to press the overhang edges of the masking tape inward to create a smooth fit. When you have a rather smooth push-pull action (for focusing), cut the masking tape in a diagonal cut that is shorter at the base end, and which gradually gets longer toward the flange end. This will give a tighter fit the farther you twist the focuser into the tube.
Using the 1" tape, wrap about two rounds of tape around the base of the eyepiece, STICKY SIDE OUT. Then, begin wrapping tape around the slip bushing (STICKY SIDE DOWN) onto the bushing that you have just created, and continue until the eyepiece fits into the PVC bushing, and can be moved in and out in a smooth push-pull motion. This provides fine tuning for your focusing mechanism. Again....when you cut the tape, cut it in a long diagonal that increases towards the eyepiece lens, so that when you push the eyepiece in, it gets tighter.
NOTE: The push-pull focusing shouldn't be a drastic change from loose to extremely snug. There should be only a slight change in resistance. You don't want either the bushing or the eyepiece to be loose enough to fall out if the telescope were held in an upright position with the main objective pointing upward. Neither do you want them to be so tight that you can't easily push or pull them for focusing. The key here is trial and error. You are going to have to experiment a bit to get the tape wrapped at the ideal length. Cutting long gives you something to work with, so that you can cut inches or portions of inches off to fine tune the mechanism.
After getting the focusing mechanisms operational, you are through...unless you want to decorate the PVC tubing a bit and make it look nicer. White contact paper gives a smooth, finished look to your telescope, but any kind of contact paper will do...you may personalize the 'scope to your own taste. Burled wood contact paper with gold diffraction grating trim is particularly nice. You may want to consider using metallic trims or contrasting colored contact paper for the edges of the 'scope to give it a more "finished" look. If you want to use metallic shim stock, use thin stock. Brass or aluminum are flexible enough in a lightweight sheet. If children will be involved in the construction process, however, it is better to use contact paper. Thin, metallic sheets can deliver nasty cuts, and they are slightly difficult to work with.
If you want to mount your telescope onto a camera tripod, find the balance point of the completely assembled telescope by placing it on a table with a pencil underneath the tube. Move the pencil around until the telescope is well balanced on top of the pencil. Mark this point. Drill at this point with a 3/16" inch drill bit and tap with a 1/4" X 20 (threads to match the camera tripod screw) tap. The telescope may then be screwed directly onto your camera tripod platform.
* Sources for main objectives and Kellner eyepieces:
Apogee Inc.--(Specializing in Optical Surplus)
E-Mail them at: firstname.lastname@example.org
Visit their web site at: http://www.apogeeinc.com/
Phone/FAX: (815) 923-1602
Call or write for a free catalog.
Postal Address: P.O. Box 136 / Union, IL 60180-0136
* The originator of the Copier Lens 'Scope and source for Copier Lens Telescope Kits or pre-made telescopes, inexpensive 25 mm Kellner Eyepieces, Erect Image Eyepieces, Baader Solar Filter material, and more is Draco Productions.
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