Interpupillary distance (IPD) is the distance between the pupils of your eyes measured from center to center when your eyes are focused on infinity. IPD
Twilight Factor is a number used to compare the effectiveness of binoculars or spotting scopes used in low light. The larger the twilight factor, the more
Compactness and ruggedness are two major features to consider when looking for a pair of binoculars. Compactness relates to whether roof, porro, or other prisms
The central focus is also called the middle axis handwheel adjustment. From the picture above, you can see that she adjusts the focus through the middle
How to properly maintain and maintain the telescope in the process of using it? In general, as long as the method is right, the maintenance
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