Askar 203APO f/7 Triplet APO Refractor
203mm Aperture Triplet Air-Spaced APO Objective 1421mm Focal Length at f/7 Includes one ED (Extra-Low Dispersion) Glass Element Retractable Tube Design for a 1145mm Minimum Length 23.5kg Gross Weight with Included Rings and Plate Description FAQ Specifications In the Box Downloads Warranty Askar 203APO f/7 Triplet APO Refractor The Askar 203APO refractor combines a massive 203mm aperture with a 1421mm focal length, delivering a native f/7 focal ratio for high-resolution planetary and deep-sky imaging. Its triplet air-spaced APO objective, which includes one ED glass element, is housed in an optical tube that weighs 18.5kg and has a transport length of just 1145mm thanks to its retractable design. 203mm f/7 Triplet APO: Correcting Color with ED Glass The heart of the 203APO is its 203mm triplet air-spaced apochromatic objective. By incorporating a piece of specialized ED (Extra-low Dispersion) glass, the optical system corrects for chromatic aberration, ensuring that stars are sharp, color-pure points of light without distracting purple fringing. This high level of color correction is critical for an instrument with this much light-gathering power, providing true-to-life colors and maximum contrast on everything from lunar craters to faint galactic dust lanes. A 1145mm Transport Length: Retractable Tube for Portability & Binoviewers Despite its large aperture, the Askar 203APO is designed for field use. A retractable dew shield allows the OTA to shrink to a transport length of 1145mm. More significantly, the rear lens tube itself is retractable, a key feature for enabling different observing setups. By contracting the rear assembly, you gain enough inward focus travel to use binoviewers without a Barlow lens, while extending it provides the correct focal point for standard 2" diagonals and eyepieces. Focuser System with 2" and 1.25" Adapters The 203APO is equipped with a large-diameter, dual-speed rack and pinion focuser built to handle the weight of heavy imaging trains without flexure or slippage. The entire focuser assembly rotates a full 360°, allowing you to perfectly frame your target without rotating the entire optical tube. For maximum flexibility, the focuser includes two finder bases and comes standard with both 2" and 1.25" adapters, ensuring compatibility with all your visual and imaging accessories. 23.5kg Mounting System: Triplet Rings and a Losmandy Plate Supporting the 18.5kg optical tube is a robust set of hardware that brings the total weight to 23.5kg. The system includes a unique set of triplet-style tube rings, providing exceptional stability and rigidity. These rings attach to a standard Losmandy-style dovetail plate, which is compatible with most high-capacity equatorial mounts. A long handle is mounted on top of the rings, which not only makes transport easier but also serves as an additional mounting point for guide scopes or other accessories. Askar 203APO vs. 185APO: The Light-Gathering Advantage of 203mm While the Askar 185APO offers excellent imaging in a more portable package, the 203APO represents a significant step up in optical power. The primary trade-off is weight; at 23.5kg, the 203APO demands a higher-capacity mount than its smaller sibling. Askar 185APO Advantage: Lighter weight and smaller physical size make it easier to transport and mount. Askar 203APO Advantage: The larger 203mm aperture gathers substantially more light, resulting in brighter images, shorter exposure times for faint deep-sky objects, and a higher theoretical resolution for splitting close double stars and resolving fine planetary detail. How does the Askar 203APO's retractable rear tube help with binoviewers? Binoviewers require a large amount of inward focus travel that most refractors do not have. The Askar 203APO's retractable rear tube solves this by allowing you to shorten the optical path. By contracting the tube, you can achieve focus with a binoviewer directly, without needing a Barlow or optical corrector that would increase magnification. What kind of mount is required for the Askar 203APO's 23.5kg weight? With a gross weight of 23.5kg (51.8 lbs) for the OTA, rings, and plate, a heavy-duty equatorial mount is essential. For reliable imaging, you should look for a mount with a manufacturer-rated payload capacity of at least 70 lbs (32kg), and preferably in the 100 lb (45kg) class to ensure stability and precise tracking. Is the Askar 203APO suitable for high-resolution planetary imaging of Jupiter or Saturn? Absolutely. The large 203mm aperture provides exceptional resolving power, while the f/7 focal ratio is a good starting point for planetary imaging. When combined with a 2.5x or 3x Barlow lens, the Askar 203APO can achieve the long effective focal lengths needed to capture fine details like the Cassini Division in Saturn's rings or cloud bands on Jupiter. What are the benefits of the 203mm f/7 triplet APO design for deep-sky objects like the Orion Nebula (M42)? The 203mm triplet APO design offers two main advantages for targets like the Orion Nebula (M42). First, the large aperture gathers a tremendous amount of light, revealing fainter, extended nebulosity in shorter exposures. Second, the apochromatic correction ensures that the bright stars of the Trapezium cluster at its core are rendered as sharp, color-pure points without chromatic aberration. Why does the Askar 203APO come with a long Losmandy dovetail plate? A long telescope like the Askar 203APO requires careful balancing on an equatorial mount, especially when adding heavy cameras, filter wheels, and guide scopes. The included long Losmandy plate provides a wide range of adjustment, making it much easier to slide the entire 23.5kg assembly forward or backward to achieve perfect balance in Right Ascension. Can I use standard 2-inch and 1.25-inch accessories with the Askar 203APO? Yes. The Askar 203APO is equipped with a large-diameter focuser that terminates in a standard 2" opening. It also includes a 2"/1.25" adapter, ensuring full compatibility with all standard eyepieces, diagonals, Barlow lenses, and camera nosepieces on the market. Aperture Size 203mm Focal Length 1421mm Focal Ratio f/7 Objective Lens Triplet air-spaced APO (including one ED glass) Total Length 1145mm (dew shield contracted) / 1335mm (dew shield stretched) OTA Weight 18.5kg Gross Weight 23.5kg (including tube rings and dovetail plate) Adapters 2" and 1.25" visual adapters 203APO OTA × 1 Tube Rings × 1 group Handle × 1 Askar 500mm Losmandy Dovetail Plate × 1 Aluminum Box × 1 Download Manual Download Manual Askar 1-Year Warranty