Askar SQA70 Quintuplet Petzval Astrograph 70mm f/4.8

Askar SQA70 Quintuplet Petzval Astrograph — 70mm f/4.8

The Askar SQA70 is a 70mm aperture, 336mm focal length, f/4.8 quintuplet air-spaced Petzval astrograph delivering sharp, flat full-frame star fields across the 44mm image circle. Two pieces of ED glass in the quintuplet optical group control chromatic aberration across the full field, and the Petzval design eliminates the need for an external flattener. With 27% more aperture than the SQA55 and a 336mm focal length that suits both wide-field nebulae and moderately framed galaxies, the SQA70 sits at a versatile middle position in the SQA Series lineup.

The rear adapter accepts M42, M48 (with built-in 2" filter thread), and M54 connections — giving the SQA70 the widest camera compatibility in the SQA Series. The dew shield retracts for transport, and the OTA ships with an Oxford cloth case. The optional SQA Series Handle Bar and Heightening Section are both compatible with the SQA70.

Who Is This Product Best For?

• Intermediate to advanced astrophotographers upgrading from smaller astrographs who want more aperture and slightly longer reach than the SQA55.
• Full-frame imagers who want a versatile focal length that works for both large emission nebulae and framing individual galaxies.
• Astrophotographers on mid-payload mounts — at 3.5kg gross, the SQA70 works well on mounts rated for 6–10kg payload.
• Dual-purpose users wanting a fast Petzval for deep-sky imaging that can also serve as a telephoto for daytime photography (no aperture iris — fixed f/4.8).

Why Choose the Askar SQA70?

• Quintuplet Petzval with 2× ED glass — flat-field, well-corrected across the full 44mm image circle at f/4.8 with no flattener needed.
• Fast f/4.8 — short exposure times for faint nebulae, ideal for narrowband imaging from light-polluted skies.
• Widest camera compatibility in the SQA Series — M42, M48, and M54 rear adapters included.
• Versatile focal length at 336mm — well-suited to large nebulae, galaxy groups, and Milky Way star fields.
• Broad back-focus range (37–68mm) — accommodates OAGs, filter drawers, and other accessories in the imaging train.
• Optional Handle Bar and Heightening Section compatible — easy to add carry handle and OTA clearance accessories.

Recommended Uses

• Wide-field and mid-focal-length deep-sky astrophotography
• Large emission and reflection nebulae, galaxy groups, star clusters
• Narrowband and broadband filter imaging
• Full-frame DSLR, mirrorless, and dedicated astronomy camera imaging
• Guided and unguided portable setups on mid-payload mounts

Compatibility and Accessory Notes

Camera connections: M42, M48 (with built-in M48×0.75 2" filter thread), and M54 adapters included. Recommended back focus 55mm; usable range 37–68mm from the rear adapter base.

Optional accessories: SQA Series Handle Bar, SQA Series Heightening Section (both compatible). An electronic focuser motor can be fitted; contact us for the correct adapter for your focuser brand.

Mount requirements: At 3.5kg gross, a mount with at least 6–8kg payload is recommended for stable imaging.

Important Limitations

• No aperture iris — the SQA70 is fixed at f/4.8. It cannot be stopped down for daytime photography the way the SQA55 can.
• Not for visual observing — no eyepiece holder or visual adapter is included or available.
• Electronic focuser not included — manual focus only; a separate motor adapter is required for automated focusing.
• Not compatible with the SQA55 Quick-Release Handle Bar or SQA55 AF Kit — those are SQA55-specific accessories.

Frequently Asked Questions

Do I need a flattener?
No. The Petzval quintuplet design provides a flat field natively across 44mm.

How does the SQA70 compare to the SQA55?
The SQA70 has more aperture (70mm vs 55mm), a longer focal length (336mm vs 264mm), and wider camera compatibility (M42/M48/M54 vs M48 only). The SQA55 has an aperture iris for daytime use and ships with a military waterproof case. The SQA70 is better for imaging; the SQA55 is more portable and travel-rugged.

What is the back focus?
55mm recommended; 37–68mm usable range from the rear adapter base.

Our Recommendation

At Ontario Telescope and Accessories, we recommend the Askar SQA70 for astrophotographers who want more aperture and focal length than the SQA55 while keeping the system compact and versatile. Its broad camera compatibility, wide back-focus range, and fast f/4.8 Petzval optics make it an excellent choice for a dedicated imaging refractor on a mid-sized mount.

Optical Diagram Reports

The following diagrams cover the mechanical dimensions, camera connection specifications, locking screw positions, and electronic focuser assembly for the Askar SQA70.