The Askar 203APO is an OTA with a 203mm aperture, 1421mm focal length, and f/7 native focal ratio. The large aperture of 203mm gives it an inherent advantage in terms of light-gathering power, resolution, brightness, and contrast, allowing the photographer to gather more light (20% more than the 185APO!) and present more details and brighter objects in the image. Along with more light coming into the astrograph, the limiting magnitude can reach 13.3. The Askar 203APO adopts a triplet air-spaced APO lens design, including one piece of ED glass. The Askar APO series employs special optical designs and multiple lens elements to correct chromatic aberration, naturally providing higher-quality object details and color accuracy. In the refractor's element structure, increasing the number of lens elements and designing lens combinations can effectively improve chromatic aberration correction. However, this also means increased production costs and design complexity. ED glass, also known as low-dispersion glass, is a type of optical glass specifically designed to reduce chromatic aberration. As a large aperture, long focal ratio OTA, the Askar 203APO was designed with portability in mind. Due to the retractable lens tube design, the shortest overall length is only 1145mm, the net weight is 14.9kg, and the gross weight is 23.5kg (including the handle, tube ring, and dovetail plate). Each piece of Askar 203APO is equipped with a unique name ring for identification.The retractable design of the dew shield, along with the enlarged locking screws, provides convenient usage. The 203APO's tube ring has an enhanced triplet design, which is sturdy. The thumb screws enable easy opening and locking of the tube rings. Meanwhile, the base of the tube rings is heightened, providing more space. The Askar 203APO has an extended 402mm handle with a special slot design, making it also a base for installing a finder scope. The dovetail plate of the Askar 203APO is the standard Losmandy dovetail plate, which is compatible with most equatorial mounts and bases on the market. The dovetail plate is designed with multiple holes, which makes it easy to adjust the position. The length of the dovetail plate has been extended to 500mm, which is more convenient for balancing on the mount. It is worth mentioning that the rear lens tube of the Askar 203APO has an integrated retractable design. We strengthen the overall stability and ensure that the optical axis will not be affected when the lens tube is stretched, thus guaranteeing the quality of the image. The retractable part also features a rudder-type locking ring that makes it easy to loosen or tighten. When the lens tube is stretched, the 203APO can be connected to a diagonal and an eyepiece for observation. When the lens tube is contracted, the Askar 203APO can be used with a binoviewer for visual observation. In terms of the focuser, the Askar 203APO is equipped with a dual-speed rack and pinion large 3.5-inch rigid focuser, which can be compatible with most motorized focusers on the market. There is a high-precision scale printed on the 100mm focusing travel. The entire focuser barrel is CNC machined with an anti-reflective internal design and matting paint, providing extra measures to eliminate stray light. There are two finder bases on both sides of the focuser, which not only eliminates the need for disassembling when changing the position of the finder scope but also provides additional mounting positions for other astronomical accessories. The rear of the focuser features a 360° high-precision big rotator, along with precise scales for convenient adjustment and saving of rotation angles, enabling precise rotation. It is also equipped with an enlarged rotator locking screw that can be easily secured even under high loads. In terms of visual observation, the focuser interface at the rear comes with a 1.25"/2" adapter， so the 203APO can easily achieve focus when connected to 1.25" or 2" diagonals or various eyepieces. Because of the retractable lens tube design, it can also be attached to a binoviewer for visual observation. The entire Askar 203APO tube is crafted using high-quality CNC machining with anodized and surface spray paint treatments. The orange accents on the ivory-white tube add a bright and eye-catching touch, presenting a stylish and elegant overall appearance. Later, the specialized Askar 203APO reducer and flattener will also be launched, giving more possibilities for the Askar 203APO. Specifications Aperture size 203mm Focal length 1421mm Focal ratio f/7 Objective lens Triplet air-spaced APO (including one ED glasses) Total length（ without accessories） 1145mm (when dew shield is contracted) Total Weight 23.5 kg (with tube ring and dovetail) Rear-end adapter type 2" adapter, 1.25" adapter Product Size Diagram Instruction of using the 203APO retractable lens tube (for eyepiece observation, 1.0x flattener, and 0.8x reducer) The Locking Screw Position Diagram 203APO EAF (optional) Installation Optical Path Diagram
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