SVBONY SV503 70mm f/6.78 Quadruplet Telescope Launched

SVBONY has slowly but surely carved a niche in the astrophotography world. Known for budget-friendly optics with surprising quality, svbony continues to impress beginners and seasoned imagers alike. The latest offering, the SV503 70mm f/6.78 Quadruplet ED Flatfield Refractor, represents a significant advancement. It's compact. It's powerful. And it's purpose-built for wide-field imaging on APS-C sensors. This telescope checks several boxes: high optical quality, flat imaging field, built-in field flattener, and ED glass. All of this comes in a manageable size. If you're looking for a travel-friendly deep sky telescope, this one deserves serious attention.

Design and build: Compact and solid

The SV503 70mm f/6.78 sports a sleek design. The telescope features a white aluminum tube with an anodized orange trim. It's striking yet professional. The retractable dew shield keeps things compact while protecting the optics. Fully extended, the scope is just over 300mm in length, making it ideal for travel. It weighs around 2.5 kg, which puts it in a sweet spot for lightweight equatorial mounts like the Sky-Watcher Star Adventurer GTi or iOptron SkyHunter. Build quality is excellent for its class. The CNC-machined tube, metal accessories, and precision-finished focuser give it a premium feel. No plastic here. Just metal where it matters.

Optics: Quadruplet for perfection

This is where the SV503 70mm truly shines. It features a quadruplet optical design, four lens elements in two groups. What sets it apart is the integrated field flattener. You don't need to buy or attach a separate flattener. This alone saves cost, complexity, and potential for alignment errors.

Its 70mm aperture and 474mm focal length give it a focal ratio of f/6.78. That's fast enough to gather significant light yet long enough to avoid heavy distortions in star shapes. The scope uses ED (Extra-low Dispersion) glass in one of its elements. This glass minimizes chromatic aberration, those annoying color fringes you sometimes see around stars. The result is tighter stars and sharper images across the field.

Built-in field flattener

Most budget refractors suffer from edge distortion. Stars stretch, smear, or even appear comet-like, especially when using large sensors. That’s where a field flattener becomes necessary. This telescope solves that problem internally. The built-in 4-element flattener corrects edge distortion for APS-C sensors. You get pinpoint stars from corner to corner. No need for adapters, spacers, or trial-and-error backfocus tuning. This integrated solution is a huge advantage for beginners and anyone wanting a clean, hassle-free setup.

Focuser: Dual-speed precision

Focusing is one of the most critical tasks in astrophotography. Even a slight misfocus can ruin a perfect exposure. SVBONY equips this scope with a 2.4-inch dual-speed rack-and-pinion focuser. You get coarse and 1:10 fine focus knobs. The focuser supports up to 6 kg of imaging payload, which covers most DSLRs, mirrorless cameras, and cooled CMOS cameras. It includes a 360° rotator, letting you frame your shot perfectly without disturbing focus. The focuser also features a built-in tension control and locking mechanism, both essential for maintaining focus through a long imaging session.

Imaging compatibility

SVBONY designed the SV503 70mm f/6.78 specifically for APS-C sensor cameras. These include most DSLR and mirrorless models from Canon, Nikon, Sony, and dedicated astronomy cameras like those from ZWO and QHY. The field is flat enough to ensure stars stay round at the corners. With its short focal length, the scope captures wide swaths of sky, making it ideal for nebulae, open clusters, and large galaxies. Pair it with a cooled monochrome camera and narrowband filters, and you're ready for deep sky imaging, even from light-polluted suburbs.

Who is it for?

This telescope is targeted at beginner to intermediate astrophotographers. It's for people who:

• Want sharp stars across APS-C sensors
  Prefer an integrated flattener over buying one separately
  Need a lightweight, travel-friendly rig
  Want excellent color correction without spending thousands

If you already have a doublet and an external flattener, this might feel redundant. But if you’re starting fresh or looking for an upgrade from an entry-level achromat, this scope delivers major value.

Key specifications

• Aperture: 70mm/2.8″
  Focal length: 474 mm/18.7″
  Focal ratio: f/6.78
  Objective type: 2-Element ED lens with FPL51 and lanthanum special glass
  Corrector: 2-element corrector installed in the tube
  Focuser: 2.5″ RAP focuser with 2″ reduction adapter and M54x0.75 female thread
  Tube length (min): 365mm/14.4″
  Tube diameter: 82mm/3.2″
  Dew shield diameter: 93 mm/3.7″        
  Tube weight incl. accessories: 2685g/5.9lb

Price and availability

The SVBONY SV503 is priced at $399.99. It will be available for pre-sale from June 20, 2025, via the official website.

The SVBONY SV503 70mm f/6.78 Quadruplet is one of the most impressive refractors in its price class. It offers features usually found in scopes costing two or three times as much. The built-in field flattener alone sets it apart from most 70mm scopes. It's small but powerful. Simple but capable. And most importantly, it produces flat, clean astrophotos with minimal effort. If you're venturing into deep sky astrophotography and want a no-fuss experience, this scope is a worthy contender. You don't need an extra glass or trial-and-error setups. You just need clear skies.

Clear skies!