Askar SQA85 Quintuplet Petzval Astrograph 85mm f/4.8

Askar SQA85 Quintuplet Petzval Astrograph — 85mm f/4.8

The Askar SQA85 is an 85mm aperture, 408mm focal length, f/4.8 quintuplet air-spaced Petzval astrograph incorporating two pieces of SD glass for high-grade chromatic aberration correction across its full-frame image circle. As the mid-range model in the SQA Series, the SQA85 steps up from the SQA70 with a significantly larger 85mm aperture and 408mm focal length — the same focal length as the Askar 60F, but delivered at f/4.8 vs f/6.8, meaning dramatically faster light collection and shorter required exposures.

The Petzval optical design provides a flat field natively, eliminating the need for a separate field flattener. Rear adapter options include M48, M54, and M68, making the SQA85 compatible with medium-format astrocameras. The optional SQA Series Handle Bar and Heightening Section are compatible, and the OTA ships in an Oxford cloth carry case.

Who Is This Product Best For?

• Advanced astrophotographers seeking a large-aperture, flat-field imaging refractor at a fast focal ratio.
• Full-frame and medium-format imagers who want a Petzval astrograph with M68 connection compatibility for larger sensors.
• Deep-sky imagers targeting faint nebulae and galaxies who benefit from the 85mm aperture and f/4.8 speed to shorten total integration time significantly.
• Astrophotographers on medium-to-large payload mounts — at 4.62kg gross, a mount rated for at least 8–10kg is recommended.

Why Choose the Askar SQA85?

• Two pieces of SD glass — superior chromatic aberration correction compared to standard ED glass designs.
• Fast f/4.8 with 85mm aperture — significantly more light-gathering than smaller aperture or slower focal ratio alternatives.
• M48, M54, and M68 rear adapters — compatible with medium-format astrocameras and the widest range of dedicated astronomy cameras.
• No external flattener required — flat-field Petzval design covers the full 44mm image circle natively.
• Broad back-focus range (40–70mm) — accommodates filters, OAGs, and accessory adapters.

Recommended Uses

• Advanced deep-sky astrophotography (faint nebulae, galaxy fields, star-forming regions)
• Narrowband imaging (Hα, OIII, SII) from suburban and light-polluted sites
• Full-frame and medium-format camera imaging
• Long-integration imaging sessions on medium-to-large equatorial mounts

Compatibility and Accessory Notes

Camera connections: M48, M54, and M68 adapters included. Built-in M48×0.75 2" filter thread. Recommended back focus 55mm; usable range 40–70mm.

Optional accessories: SQA Series Handle Bar, SQA Series Heightening Section (both compatible). Electronic focuser motor fitting is possible with appropriate adapter.

Mount requirements: Minimum 8–10kg payload recommended for stable imaging with the SQA85.

Important Limitations

• Not for visual observing — no eyepiece holder or visual adapter is available.
• Electronic focuser not included — manual focus only without a separately purchased motor adapter.
• Requires a capable mount — at 4.62kg gross, lightweight tracking mounts are not suitable for stable long-exposure imaging.

Frequently Asked Questions

How does the SQA85 compare to the SQA70?
The SQA85 has 85mm vs 70mm aperture, 408mm vs 336mm focal length, SD glass vs ED glass, and M68 compatibility for larger sensors. It collects more light per unit time but requires a heavier mount.

Do I need a flattener?
No. The Petzval quintuplet design provides a flat field natively.

What sensors does it cover?
The 44mm image circle covers all full-frame sensors. M68 adapters allow connection to medium-format astrocameras up to 55mm diagonal.

Our Recommendation

At Ontario Telescope and Accessories, the Askar SQA85 is our recommendation for advanced astrophotographers ready to step up to a larger-aperture, faster Petzval system. The two pieces of SD glass, M68 adapter compatibility, and f/4.8 speed make it an excellent choice for serious narrowband and broadband imaging on a mid-to-large equatorial mount.

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