Askar 151PHQ f/7 Quadruplet Astrograph
151mm Aperture Quadruplet APO Optics 1057mm Focal Length at f/7 Integrated Flattener for a 60mm Image Circle Includes Two ED Glass Elements for Color Correction 13.7kg Total Weight with Rings and 300mm Dovetail Plate Four-Piece Adapter Set for Direct Camera Connection Description FAQ Specifications In the Box Downloads Warranty Askar 151PHQ f/7 Quadruplet Astrograph The Askar 151PHQ combines a massive 151mm aperture with an integrated flat-field quadruplet optical design, delivering a 1057mm focal length at a native f/7. This astrograph is engineered to illuminate a 60mm image circle without requiring an external flattener, eliminating complex backfocus calculations. With two ED glass elements for superior color correction and a total weight of 13.7kg, the 151PHQ provides the light-gathering power and image scale for capturing detailed, wide-field views of deep-sky objects. 151mm f/7 Quadruplet APO Optics with 2 ED Elements The heart of the 151PHQ is its air-spaced quadruplet objective, which uses two extra-low dispersion (ED) glass elements to achieve apochromatic correction. This design aggressively suppresses chromatic aberration, ensuring stars are rendered as sharp, color-pure points without distracting halos. At 151mm of aperture and a 1057mm focal length, this instrument captures faint details on galaxies and nebulae with high resolution, making it ideal for serious deep-sky imagers. A 60mm Flat Field: No External Flattener Required Unlike traditional refractors, the 151PHQ features a built-in field flattener as part of its core optical design. This Petzval-like configuration produces a corrected, flat 60mm image circle, fully illuminating large full-frame and medium-format sensors without any additional hardware. You can attach your camera directly via the included adapters and start imaging, confident that stars will remain round and sharp from the center to the corners of your frame. Imaging-Ready Mechanics: 13.7kg OTA with a 3.4" Focuser Engineered for stability, the 151PHQ weighs 11.6kg as an OTA and 13.7kg fully equipped with its tube rings and 300mm Losmandy-style dovetail plate. This substantial build requires a high-capacity mount but rewards you with a rigid imaging platform. The heavy-duty 3.4-inch rack-and-pinion focuser provides precise, no-slip control over focus, even with heavy camera payloads, and includes a 360° rotator for effortless image framing. Telescopic Dew Shield: Contracts the OTA length to 930.3mm for transport and extends to 1117.8mm to block stray light and prevent dew formation. CNC-Machined Tube: The entire optical tube is built for rigidity and thermal stability, ensuring focus remains consistent throughout an imaging session. Finder Base: A standard finder shoe is included for attaching your preferred guide scope or finder. Complete Mounting & Connection System: 300mm Plate and 4 Adapters The 151PHQ arrives ready to integrate into your setup. It includes a pair of robust tube rings, a multi-function carrying handle, and a 300mm Losmandy-style dovetail plate for secure attachment to your mount. To connect your camera, a set of four threaded adapters is provided, stepping down from the focuser's native M86x1 thread to the universal M48x0.75 thread used by most cameras and filter wheels. Askar 151PHQ vs. 130PHQ: Aperture and Portability As the largest instrument in Askar's PHQ line, the 151PHQ is the direct successor to the popular 130PHQ for imagers seeking more resolving power and light grasp. Askar 130PHQ Advantage: The 130PHQ is significantly lighter and more compact. Its lower weight makes it compatible with a wider range of medium-payload mounts, offering greater portability. Askar 151PHQ Advantage: With a 151mm objective, the 151PHQ gathers 34% more light than the 130mm model, allowing you to capture fainter details or reduce exposure times. Its longer 1057mm focal length also provides greater image scale, making it better suited for resolving details in smaller galaxies and planetary nebulae. Does the Askar 151PHQ require a separate field flattener? No. The Askar 151PHQ has a built-in flattener as part of its quadruplet optical design. It produces a flat 60mm image circle natively, so you do not need to purchase or calculate backfocus for an external flattener. What kind of astronomical mount is needed for the Askar 151PHQ? With a total weight of 13.7kg (30.2 lbs) plus the weight of your camera and guide scope, a heavy-duty mount is essential. Look for mounts with an instrumental capacity of at least 50-60 lbs (22-27 kg) to ensure stable, precise tracking for long-exposure astrophotography. How will the Askar 151PHQ frame large targets like the Andromeda Galaxy (M31)? The 1057mm focal length provides an ideal image scale for large galaxies and nebulae when paired with a full-frame sensor. On a typical full-frame camera, M31 will be tightly framed, showcasing its core, dust lanes, and outer arms in a single, high-resolution shot. What does the 60mm image circle of the 151PHQ mean for my camera choice? The large 60mm image circle fully illuminates sensors up to medium format size without vignetting. This makes the 151PHQ compatible with: Full-Frame (36x24mm) DSLR/Mirrorless and Astro Cameras: These will be fully covered with excellent corner-to-corner star quality. Medium-Format (e.g., 55mm diagonal) Astro Cameras: Even the largest consumer sensors will be illuminated, allowing you to capture immense fields of view. Is the 151PHQ's 1057mm focal length good for smaller galaxies like the Whirlpool Galaxy (M51)? Yes, the 1057mm focal length provides excellent image scale for resolving details in medium-to-small deep-sky objects. With the 151mm aperture, you can capture the spiral structure of M51, the bridge connecting it to its companion galaxy NGC 5195, and individual HII regions with impressive clarity. What is the advantage of the quadruplet design in the Askar 151PHQ? The four-element (quadruplet) design with two ED glass elements allows for a higher degree of optical correction than simpler doublet or triplet designs. It corrects for chromatic aberration (color fringing), spherical aberration, and field curvature simultaneously, resulting in a sharp, flat, color-pure image across the entire 60mm field without needing extra accessories. Aperture 151mm Focal Length 1057mm Focal Ratio f/7 Objective Design Quadruplet Air-Spaced APO (with 2 ED elements) Image Circle 60mm OTA Weight 11.6 kg Total Weight 13.7 kg (including tube rings & dovetail plate) Total Length (Observing) 930.3mm (dew shield contracted) to 1117.8mm (dew shield stretched) Total Length (Imaging) 976.8mm (dew shield contracted) to 1164.3mm (dew shield stretched) Included Adapters M86×1 to M68×1M68×1 to M54×0.75M54×0.75 to M54×0.75M54×0.75 to M48×0.75 (with M48 filter thread) 151PHQ OTA × 1 Tube Rings × 1 Pair Carrying Handle × 1 Askar Losmandy 300mm Dovetail Plate × 1 4-Piece Photographic Adapter Set × 1 Aluminum Hard Case × 1 Download Manual Download Manual Askar 1-Year Warranty