Adaptation Objectif MC MTO-11CA 1000 mm F/10 au standard µ4/3

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Conversion of a Russian MC MTO-11CA Super Telephoto Lens to Micro 4/3 (MFT) standard for astrophotography purposes. This Maksutov mirror telephoto lens, manufactured in Russia, features a 49 mm diameter exit with a groove. Available T2 adapters include models compatible with μ4 / 3 or M42x1 to μ4 / 3. To connect an adapter in my possession directly to this Telelens, I chose not to use commercial options. The threaded ring T2 (M42x0.75) is secured by three HC M3x4 screws and has a mounting diameter of 52 mm. The space between the adapter and the lens exit collar is significant, making centering difficult to achieve. To address this issue, I designed and printed a small PETG ring that evenly fills this gap, ensuring the adapter's centering with the Telelens's optical axis while allowing for a minimal focus offset at infinity. Additionally, I replaced the original screws with HC M3x6 screws to compensate for the space. The Micro 4/3 format offers a conversion factor of x2 compared to a 24x36 FF collector, without any loss of brightness. As a result, this 1000mm F10 frame behaves like a 2000mm F10 Full Frame, making it suitable for photographing the Moon with interesting results.