Askar SQA70 Pro f/4.6 70/322 mm is an apochromatic imaging refractor by Askar, designed for wide-field deep-sky astrophotography with astronomy cameras and photographic cameras using sensors up to full-frame format. Its six-element air-spaced Petzval optical system contains one SD glass element and one ED glass element. The design combines chromatic aberration correction with a flat image field measuring 44 mm in diameter.
The rack-and-pinion focuser with coarse and fine adjustment and the graduated rotator make focusing and framing easier. M42, M48 and M54 adapters allow the connection to be matched to the imaging setup. The recommended distance from the end of the adapter to the sensor is 55 mm, while focus can be reached within a range of 36–68 mm.
• six-element Petzval optical system with SD and ED glass, designed for imaging extended nebulae and star fields
• image field covering full-frame sensors and an f/4.6 focal ratio
• 2.5" rack-and-pinion focuser with coarse and fine adjustment, a travel scale, and internal grooves and matte black surfaces to reduce stray light
• 360° rotator with an angular scale and locking screw for adjusting image orientation
• fixed, non-retractable dew shield that reduces off-axis light and protects the objective
• integrated dual tube rings with a hollowed-out structure, hand-operated locking knobs, and M4 and M6 threaded holes for attaching accessories
• dovetail plate in the Vixen style with scales on both sides to help reproduce the tube position when balancing
• two finder or accessory bases on the sides of the focuser and an additional mounting slot at the top of the tube rings
• provision for installing an optional motor focuser; the manufacturer illustrates installation using the ZWO EAF as an example
• provision for adding an optional 85 mm metal handle and a 20 mm riser
• optical tube Askar SQA70 Pro with focuser, rotator and fixed dew shield
• integrated dual tube rings
• 290 mm Vixen-style dovetail plate
• connection adapters: M42, M48 and M54
• carrying case made of Oxford fabric
• manufacturer: Askar
• model: SQA70 Pro
• instrument type: apochromatic imaging refractor
• optical design: six-element air-spaced Petzval, including one SD glass element and one ED glass element
• aperture: 70 mm
• focal length: 322 mm
• focal ratio: f/4.6
• image field diameter: 44 mm; supported sensor format: up to full frame
• spot radius (RMS) according to the manufacturer's optical diagram: 0.747 µm on-axis and 1.236 µm at 22.001 mm from the axis; optical design values, not measurements of star sizes in photographs
• relative illumination at a field radius of 22 mm: over 95% according to the manufacturer's graph at a wavelength of 546 nm
• focuser: 2.5" rack-and-pinion, with coarse and fine adjustment
• focuser travel: 32 mm
• focuser adjustment: bottom load adjustment screw and separate locking screw
• rotator: 360° rotation range, angular scale and screw lock
• rotator-to-adapter connection thread: M76 × 1
• photographic connections: M42, M48 and M54 adapters; M48 adapter output thread: M48 × 0.75
• 2" filter mounting thread inside the M48 adapter: M48 × 0.75
• connection distance to the sensor: 36–68 mm, measured from the end of the installed M42, M48 or M54 adapter; recommended value: 55 mm
• tube mounting: integrated dual tube rings and Vixen-style dovetail plate
• dovetail plate dimensions: length 290 mm, width 43 mm
• accessory mounting holes in the tube rings: M4 and M6 threaded holes
• optional motor focuser mounting: M4 holes on the underside of the focuser; coarse adjustment shaft diameter: 6 mm
• dew shield: fixed, non-retractable
• total length with the focuser retracted: 331 mm
• tube outside diameter: 88 mm
• dew shield body outside diameter: 96 mm
• maximum front section diameter with the cap: 102 mm
• optical tube weight: 3 kg
• weight including tube rings and dovetail plate: 3.8 kg
The short focal length and full-frame image field allow extended objects to fit within a wide frame, while the rotator, fine focuser and several camera connection standards make the imaging setup easier to prepare.
