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Message: <blockquote data-quote="Binastro" data-source="post: 3278163" data-attributes="member: 111403">I hope that your taking the binocular apart won't invalidate any long-term warranty?Pencil marks on optics are very common. They are marked by the optical worker either to know which optic goes where, or as alignment marks. These are common on astronomical telescopes, where the best position is marked on both optical elements so when these are disassembled they can be put back correctly.With my old refractor, I found that the elements had rotated by themselves after decades of use, and I put them back where they should be. The best position was found by the old fashioned worker just by eyesight alone.When the elements are not marked it is often the case that repairers who do not know the optical instrument reassemble them incorrectly.I had this with half a dozen Leica Colorplan lenses and also with eyepieces for a Questar telescope. This meant that they were sold very cheaply as they didn't work, i.e. they didn't produce a sharp image. With the five element, I think, Leica lenses I guessed the correct positions by rotating the elements and assembling them in the correct order. And once I had reassembled the eyepieces in the correct order and the correct position the Questar telescope worked well.On the back of a 10 inch reflecting mirror there were Greek letters and Greek words. I took this to the local Greek church and the person in charge told me that it was a biblical passage that the mirror maker had put on the back of the mirror. I found out who the mirror maker was. He also apparently sometimes used to write Latin inscriptions on the back or sides of his mirrors.Sometimes one finds that optics were made by the very best makers, who have left their initials on the optics.When disassembling optics it is actually important to mark where the lens elements should go.</blockquote>

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