Astrographe Super Apo Askar SQA55

SQA55 - Super Quintuplet Astrograph

The SQA55 is an air-spaced quintuplet astrograph, designed to offer exceptional image quality and versatility for everyday astronomical photography. It's the perfect choice for anyone looking for a versatile, competition-quality lens they can take anywhere! The quality of its manufacture and optics make this little spotting scope a powerful ally for wide-field photography.

Examples of use

• Photographing comets in detail
• Imaging the sky's great nebulae in their starry field
• Detail certain conjunctions (e.g. Venus, Jupiter and Mars)
• Ideal for creative framing
• Lightweight for spontaneous use in the evening or at unexpected events

Optical design and data

• Lens system : The SQA55 uses a Petzval quintuplet optical design with SD and ED lenses to reduce chromatic aberrations and deliver image precision. This design achieves high resolution and contrast with low light loss, guaranteeing sharp, precise stars.
• MTF (Modulation Transfer Function) : The modulation transfer function (MTF) measures the sharpness of a lens by analyzing the clarity of even fine details in the image. The SQA55 maintains an MTF greater than 0.9, even at low frequencies (10 LP/mm), even at the edge of the frame, ensuring clear, sharp stars without loss of contrast.
• Relative Illumination (IR) : The SQA55 maintains a high illumination of around 90 % right to the edges of the frame, minimizing vignetting effects by ensuring that light is evenly distributed from the center to the corners of the image.
• Spot Diagram : The precision of the SQA55 is demonstrated by a central impact point with an RMS radius of less than 2.5 µm, and less than 4 µm at the edges, offering fine, detailed star imaging.
• ZYGO Objective Chart : Tested with a ZYGO interferometer, the SQA55 demonstrated high-quality results in terms of image sharpness.

Structure and mechanical characteristics

• Petzval structure: Self-plane design, without the need to calculate a specific back focus, with a connection distance between 50 mm and 60 mm for direct use in photography.
• Double-speed focuser: Allows independent fine and coarse adjustments, with imperial and metric graduations. For astrophotography, an infinity marker and additional play space offer great flexibility.
• Double rotator : The lens barrel and 360° rotator feature independent locking screws for easy adjustment and memorization of angles when shooting.

Accessories and connectivity

• Thread for M67 filter : Located on the front of the lens, it can be used to connect filters for everyday photography.
• Filter thread : Equipped with an M48 adapter with integral thread for 2" filters.
• Quick-release base : Four multi-functional bases allow you to connect various accessories for photography and astrophotography.
• Reversible lens hood : Special design with storage space on the lens tube to save space.
• Handle : The handle, with a slot for a finder base, allows various astronomical accessories to be connected and can be quickly removed without tools.

Installation structure

• Dovetail plate : 200 mm Vixen-style plate with hand screws and quick-release button for easy tripod mounting.
• Support: The bottom bracket is equipped with 1/4 and 3/8 screw holes for mounting the SQA55 on a tripod.

Diversified use cases

• Photograph of comets with details
• Deep-sky astrophotography (nebulae, galaxies, clusters)
• Capture conjunctions (e.g. Venus, Jupiter and Mars) and create original framings
• Lightweight for spontaneous use in the evening or at unexpected events
• Compatible with astronomical cameras or SLR/hybrid cameras for dual use in astrophotography and everyday photography

Carrying case

• Robust carrying case : Supplied with the SQA55, this two-tiered, waterproof, military-grade case with EVA interior provides extra space for astronomical or photographic accessories.