*Eyepiece diameter measurements are an approximation only. If your optic isn't listed, please provide your measured eyepiece diameter to our support staff for help determining a potential compatible adapter size (see the How to Measure Your Eyepiece instructions at the bottom of this page).
How to Measure Your Eyepiece
We recommend using a caliper as it will provide the most precise measurement. We will need the measurement in thousandths of an inch or tenths of a millimeter. A ruler or measuring tape may also work as long as you are as precise as possible.
The eyepiece needs to be continuous top to bottom, with no flexible sections or foldable lips. If the body of the optic below the eyepiece is larger than the diameter of the eyepiece, note that and provide a picture of it. Clean and remove any dirt or debris to ensure an accurate measurement.
Place the jaws of the caliper around the outer edge of the eyepiece near the top surface. Carefully slide the caliper jaws together until they touch both sides of the eyepiece. Note the measurement. For accuracy, take multiple measurements at slightly different positions around the eyepiece and confirm consistency. If the eyepiece is tapered or conical in shape, provide the measurements for the outer diameter at the largest and smallest cross-sections along with the overall height of the eyepiece.
Email our support staff at support@ollin.co with the make/model of your optic, the measurements you took, and at least one picture showing your optic and its eyepiece. Our support staff will evaluate the information you provide and recommend an adapter to test fit assuming there is one that we think will work.