Askar SQA85 85mm f/4.8 Quintuplet APO
- 85mm Aperture
- 408mm Focal Length (f/4.8)
- Quintuplet Petzval APO Optical Design
- Supports Full-Frame (44mm) Image Circle
- 3.64kg OTA Weight
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.
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.
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.
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.
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.
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.
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.
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.
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.
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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