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Askar SQA85 85mm f/4.8 Quintuplet APO
Askar SQA85 85mm f/4.8 Quintuplet APO
Askar SQA85 85mm f/4.8 Quintuplet APO
Askar SQA85 85mm f/4.8 Quintuplet APO
Askar SQA85 85mm f/4.8 Quintuplet APO

Askar SQA85 85mm f/4.8 Quintuplet APO

par Askar
UGC ASK-SQA85
CA$3,353.00 - CA$3,353.00
CA$3,353.00
CA$3,353.00 - CA$3,353.00
CA$3,353.00
Égalisation de prix!
  • 85mm Aperture
  • 408mm Focal Length (f/4.8)
  • Quintuplet Petzval APO Optical Design
  • Supports Full-Frame (44mm) Image Circle
  • 3.64kg OTA Weight
1 en stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Askar SQA85 85mm f/4.8 Quintuplet APO

    The Askar SQA85 is a dedicated astrograph designed around a 5-element Petzval optical system, delivering a natively flat field at a fast f/4.8 focal ratio from its 85mm objective. This 408mm focal length instrument incorporates two SD glass elements for superior color correction and illuminates a full-frame image circle without requiring a separate flattener. Weighing just 3.64kg and measuring a compact 403mm with its dew shield retracted, the SQA85 provides a powerful, portable imaging platform for capturing expansive celestial targets.

    Native f/4.8 Petzval Optics: A Flat Field for Full-Frame Sensors

    The core of the SQA85 is its quintuplet Petzval APO objective, an integrated design that eliminates the need for a separate field flattener. This f/4.8 system provides sharp, pinpoint stars across a full-frame sensor right out of the box. The 408mm focal length is ideal for framing large deep-sky objects like the Andromeda Galaxy (M31) or the entire Veil Nebula complex.

    To ensure high-contrast images free of false color, the optical train includes two pieces of SD (Super ED) glass. This corrects for chromatic aberration, rendering stars as neutral white points against a dark sky background, which is critical for both broadband and narrowband imaging.

    Imaging-Ready Mechanics: 3.64kg OTA with Versatile M48/M54/M68 Adapters

    With a bare optical tube assembly weight of 3.64kg, the SQA85 is light enough for a wide range of portable tracking mounts, minimizing payload demands while maximizing stability. The physical design is compact, with a total length of just 403mm when the dew shield is contracted, making it easy to transport and store.

    For secure imaging train connections, the SQA85 includes M48, M54, and M68 adapters, allowing you to directly thread your filter wheel, off-axis guider, or camera. The system supports a back focus distance from 40mm to 70mm, with the standard 55mm being the recommended distance for use with most DSLR and dedicated astronomy cameras.

    SQA85 Petzval vs. Triplet + Flattener: The Simplicity of an Integrated System

    While a traditional triplet refractor combined with a separate field flattener offers modularity, it also introduces complexity and potential sources of error. The primary advantage of the SQA85's integrated quintuplet Petzval design is the elimination of spacing guesswork and potential optical tilt between the objective and the corrector.

    • Triplet + Flattener Trade-off: The main advantage of a modular system is the ability to use the telescope visually without the flattener. However, achieving a perfectly flat field for imaging requires precise, calculated spacing that can be difficult to dial in.
    • Askar SQA85 Advantage: As a single, factory-optimized system, the SQA85 guarantees flat-field performance. There is only one connection point to worry about—setting your camera sensor at the recommended 55mm back focus. This reduces potential flexure points and simplifies your setup, letting you spend more time imaging and less time troubleshooting star shapes.

  • What does the Quintuplet Petzval design of the Askar SQA85 mean for imaging?

    The Quintuplet Petzval design means the Askar SQA85 has a built-in field flattener. You do not need to purchase a separate corrector to get sharp, pinpoint stars across a full-frame sensor. It is an integrated imaging system designed to work perfectly right out of the box.

    What kind of mount do I need for the Askar SQA85?

    The SQA85 has an optical tube weight of 3.64kg and a gross weight of 4.62kg (including tube rings and a dovetail plate). A mid-sized equatorial mount with a payload capacity of 25-30 lbs (11-13 kg) or more, such as a Sky-Watcher HEQ5 or iOptron CEM26, would be an excellent match for stable, long-exposure astrophotography.

    How does the Askar SQA85's 408mm focal length perform on large targets like the Andromeda Galaxy (M31) with a full-frame camera?

    The 408mm focal length is perfectly suited for this scenario. On a full-frame sensor, the Askar SQA85 will frame the entire Andromeda Galaxy (M31), including its satellite galaxies M32 and M110, with ample room to spare. This makes it an ideal instrument for capturing the full extent of large nebulae and galaxies.

    How do I connect my camera to the Askar SQA85?

    The SQA85 includes M48, M54, and M68 threaded adapters at the rear. The most common connection is the M48x0.75 thread. You simply add the necessary extension tubes to place your camera's sensor at the recommended 55mm back focus distance from the adapter's flange.

    Is the Askar SQA85's f/4.8 focal ratio fast enough for narrowband imaging of the Cygnus Loop?

    Absolutely. The f/4.8 focal ratio is considered very fast for astrophotography. This speed allows you to gather significant signal in a shorter amount of time, which is a major advantage for narrowband imaging of faint targets like the Cygnus Loop. You can capture deep data with shorter sub-exposures compared to a slower f/6 or f/7 refractor.

    What is the benefit of the two SD glass elements in the Askar SQA85 objective?

    The two SD (Super ED) glass elements provide excellent chromatic aberration correction. This means that different colors of light are brought to the same focal point, resulting in sharp, high-contrast images without distracting purple or blue halos around bright stars.

  • Aperture 85mm
    Focal Length 408mm
    Focal Ratio f/4.8
    Objective Lens Quintuplet Petzval APO (with 2 SD glass elements)
    Format / Image Circle Full-frame (44mm)
    OTA Weight 3.64kg
    Gross Weight 4.62kg (including tube ring and dovetail plate)
    Total Length 403mm (dew shield contracted) | 439mm (dew shield stretched)
    Rear-End Thread Adapters M48, M54, M68
    Back Focus 40mm - 70mm (55mm recommended)

    • Askar SQA85 OTA

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    • Oxford Cloth Case

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  • Askar 1-Year Warranty