Adjustable Monocular Scopes

thingiverse

Here are a few simple adjustable scopes that I've created. Each scope only requires one concave lens (25mm, 38mm, or 50mm) for the eyepiece, and one convex lens (50mm or 75mm) for the objective. Magnification will typically range from 1.5x-10x depending on the focal length of your lenses. I've included a few helpful files for determining the correct focal length and distance between lenses needed to get a desired magnification. The basic assembly is as follows: 1.) The 25mm-to-50mm scope consists of a 25mm parfocal extension (optional) attached to a 25mm eyepiece plus arm, which then attaches to a 50mm objective lens and finally a 75mm adapter (optional). 2.) The 38mm-to-50mm scope also involves attaching a 38mm parfocal extension (optional) to a 38mm eyepiece plus arm, followed by a 50mm objective lens, and ending with a 75mm adapter (optional). 3.) The 50mm-to-75mm scope includes only a 50mm eyepiece attached directly to a 50mm arm, which then attaches to a 75mm objective lens. **Notes** – A parfocal extension is necessary for higher magnification that requires more distance between the eyepiece and objective lens. – I separated the 50mm eyepiece and 50mm arm models to make printing easier. – Higher magnifications will display greater spherical aberration (unless achromatic lenses are used). – Using a powerful concave lens (focal length = -5cm or smaller) makes it easier to achieve higher magnification at shorter distances. – Your convex lens likely needs a focal length between 10cm and 20cm. Let me know if you have any questions.