For the visual observation of celestial objects you need eyepieces. We offer a broad range of eyepieces – starting from a beginners choice up to hyper wide field reference eyepieces, like our 9mm 120°. Eyepieces do not only differ in prices – the important factors are focal length, comfort of viewing, sharpness and contrast in the middle and at the edge of the field and the apparent field of view. The focal length of a eyepiece determines the magnification that the telescope has on the sky. The focal length of the telescope divided by the focal length of the eyepiece equals the magnification.
As an example: our 127mm apochromat has a focal length of 952mm. Using a eyepiece with a focal length of 9mm will create a magnification of 106-times. For this telescope nearly all our eyepieces work well – you will have a pleasant and sharp image with high contrast. For our f/3,9 PhotoNewtons it is not that easy – here you will get the optimal sharpness with the best (and most expensive) eyepieces only. If you are looking through three different eyepieces with the same focal length (but with different apparent fields) with your telescope you will notice that the diameter of the field of view on the sky is different. Let us try our 8,8mm 82° ultrawidefield eyepiece, a 9mm 100° hyperwidefield eyepiece and our 120° “edgeless” reference eyepiece. All three eyepieces deliver a sharp image with high contrast. The diameter of the part of the sky that you are observing will differ – with the 120° reference eyepiece you see a much larger part of the sky than in the 82°-eyepiece. Roughly speaking you are watching the sky through the 82° eyepiece as you were watching it through a short barrel. When you look through the 120° eyepiece the barrel vanishes and the view becomes borderless.