Small APO refractor telescope comparisons

The telescope market is brimming with small apochromatic (APO) refractors, offering an exciting yet sometimes overwhelming array of choices for visual astronomers and astrophotographers alike. With so many high-quality options available, it can be challenging to determine which one truly stands out. However, a well-designed small APO refractor can deliver exceptional performance—often matching or even surpassing larger telescopes in sharpness, contrast, and portability. This is why it's crucial to examine the finer details of each model to find the perfect fit for your specific needs.

Some of the most popular small APO refractors gaining recognition in the astronomy community include the William Optics RedCat 51, Askar FRA400, Sky-Watcher Evostar 72ED, Stellarvue SVX80T, and Takahashi FS-60CB, among others. Each of these telescopes has unique strengths, making the choice dependent on your particular goals—whether you’re after wide-field imaging, deep-sky astrophotography, or a compact travel-friendly scope.

For those seeking real-world comparisons, Nebula Photos' astrophotographer Nico Carver recently conducted a telescope shootout, testing nine apochromatic refractors to evaluate their performance on the GTi mount, and overall astrophorography performance of the scope. His findings provide good insight into how these telescopes stack up in terms of optical quality, portability, and imaging performance, helping users make an informed decision in an increasingly competitive market.

Which nine small APO refractor telescope comparisons where in the roundup?

This detailed analysis includes optical performance, mechanical features, and suitability for the GTi’s limited weight capacity. The contenders in this ultimate shootout include:

• Takahashi FS-60CB
• Founder Optics Draco 62
• Starfield Gear60 Quad
• William Optics Redcat 51
• Askar SQA55
• Askar 71f
• Svbony SV555
• Apertura 60EDR
• Askar FMA 180 Pro
   

Before diving into telescope performance, Nico lays out the parameters of his testing setup. He used two separate GTi mounts—one purchased personally and another loaned by Sky-Watcher USA. The imaging cameras included a ZWO ASI2600 Air and a 2600 Duo, both on long-term loan from ZWO.

The telescopes were tested under controlled conditions from his Bortle 3 backyard in New Hampshire, ensuring that each scope was imaged with no moonlight interference. The chosen deep-sky target, Van den Bergh 31, was captured when it was at least 50° above the horizon, minimizing atmospheric distortion.

Takahashi FS-60CB ($1,950 configured with reducer)

As one of the most premium options in this shootout, the Takahashi FS-60CB has an established reputation for quality. First introduced in 1999, this fluorite doublet refractor remains a top-tier choice. With the 0.72x reducer, it achieves a 255mm focal length at f/4.2, making it one of the fastest optics in this review.

Pros:

• Superior color correction with fluorite glass
• Lightweight at just 2kg (4.2 lbs)
• Excellent optical quality with minimal aberration
   

Cons:

• Expensive ($1,950 fully configured)
• Non-standard Takahashi thread connections require additional adapters

Nico confirms that the FS-60CB performs well on the GTi, providing excellent results even in moderately windy conditions.

Founder Optics Draco 62 ($1,099)

The Draco 62 is part of Founder Optics’ high-quality refractor lineup, featuring a quintuplet lens system with a built-in field flattener and an included 0.83x reducer. This results in a 250mm focal length at f/3.9, making it the fastest telescope in the test.

Pros:

• High-speed imaging at f/3.9
• Includes multiple accessories
• Premium build quality
   

Cons:

• Heavier at 6.2 lbs (3 kg)
• Slightly softer stars compared to competitors
   

While it offers excellent light-gathering ability, its heavier weight and moment arm make it less than ideal for the GTi unless additional stabilization is used.

Starfield Gear60 Quad ($1,050)

A quadruplet apochromatic refractor, the Gear60 has an FPL-53 glass element, giving it a 300mm focal length at f/5.

Pros:

• Well-controlled star shape
• No need for additional flatteners or reducers
• Good build quality
   

Cons:

• Heavier than optimal for the GTi
• Slight tilt issues in some sample images
   

The Gear60 delivers great optical correction, but its weight of nearly 3kg makes balancing on the GTi difficult.

William Optics Redcat 51 ($850)

A favorite among astrophotographers, the Redcat 51 has a quadruplet Petzval design with an FPL-53 element and a 250mm focal length at f/4.9.

Pros:

• Lightweight and GTi-friendly at 1.8kg (4 lbs)
• Sharp optical performance
• Integrated Bahtinov mask
   

Cons:

• Slightly softer stars compared to newer designs
• No space for a camera in its included case
   

Nico concludes that the Redcat 51 remains one of the best options for the GTi, balancing weight, image quality, and ease of use.

Askar SQA55 ($795)

With a quintuplet lens design and both ED and SD glass, the Askar SQA55 delivers the sharpest results among all tested telescopes.

Pros:

• Exceptional optical sharpness
• Very little chromatic aberration
• Compact and lightweight
   

Cons:

• Highly sensitive to guiding errors
• Some mechanical connection concerns
   

Though sharp, its sensitivity to tracking errors makes it challenging on the GTi without upgrades.

After thorough testing, Nico categorizes the telescopes based on their suitability for the GTi:

Best for Beginners & GTi Compatibility:

• Askar FMA 180 Pro - Best lightweight option; perfect for beginners
• William Optics Redcat 51 - Excellent performance, widely recommended
• Svbony SV555 - Affordable, good correction, easy setup
• Apertura 60EDR - Budget-friendly doublet with solid performance

Workable with Heavier Tripod/Stabilization:

• Takahashi FS-60CB - Expensive but premium optics
• Founder Optics Draco 62 - Excellent field of view, slightly soft stars
• Starfield Gear60 Quad - Sharp but heavy

Not Recommended for the GTi:

• Askar 71f with reducer - Too heavy and long for GTi’s limited payload
   

In the search for the best refractor telescope for the Sky-Watcher Star Adventurer GTi, weight and balance are just as important as optical performance. While premium options like the Takahashi FS-60CB and Founder Optics Draco 62 offer excellent image quality, their weight pushes the limits of the GTi.

For beginners, the Askar FMA 180 Pro and William Optics Redcat 51 remain the top choices, offering a blend of affordability, sharpness, and GTi-friendly weight. Advanced users seeking sharper optics can opt for the Askar SQA55, provided they employ a more stable mounting system.

Ultimately, the GTi excels with lightweight, short focal length refractors, making the FMA 180 Pro the best recommendation for newcomers entering the exciting world of deep-space astrophotography.

My Biggest Telescope Shooutout

 

Takahashi FS-60CB specifications

• Aperture: 60 mm
• Focal Length: 355 mm
• Focal Ratio: f/5.9
• Objective Lens: Fluorite doublet
• Coatings: Hard multicoatings
• Optical Tube Length: 440 mm
• Optical Tube Diameter: 80 mm
• Weight: 1.4 kg (3.08 lbs)
• Focuser: Rack-and-pinion
• Price: $1,040
   

Founder Optics Draco 62 specifications 

• Aperture: 62 mm
• Focal Length: 400 mm
• Focal Ratio: f/6.5
• Objective Lens: FPL-53 ED doublet
• Coatings: Fully multi-coated
• Optical Tube Length: 300 mm
• Optical Tube Diameter: 70 mm
• Weight: 2.5 kg (5.5 lbs)
• Focuser: 2.5" dual-speed rack-and-pinion
• Price: $1,099
   

Starfield Gear60 Quad specifications

• Aperture: 60 mm
• Focal Length: 300 mm
• Focal Ratio: f/5
• Objective Lens: Quadruplet design with FPL-53 element
• Coatings: Fully multi-coated
• Optical Tube Length: 285 mm
• Optical Tube Diameter: 80 mm
• Weight: 2.8 kg (6.2 lbs)
• Focuser: 2.5" dual-speed rack-and-pinion
• Price: $1,050
   

William Optics Redcat 51 specifications

• Aperture: 51 mm
• Focal Length: 250 mm
• Focal Ratio: f/4.9
• Objective Lens: Quadruplet Petzval design with FPL-53 element
• Coatings: Fully multi-coated
• Optical Tube Length: 225 mm
• Optical Tube Diameter: 80 mm
• Weight: 1.47 kg (3.24 lbs)
• Focuser: Helical
• Price: $850
   

Askar SQA55 specifications

• Aperture: 55 mm
• Focal Length: 300 mm
• Focal Ratio: f/5.5
• Objective Lens: Quintuplet design with ED and SD glass
• Coatings: Fully multi-coated
• Optical Tube Length: 290 mm
• Optical Tube Diameter: 70 mm
• Weight: 1.6 kg (3.5 lbs)
• Focuser: 2" dual-speed rack-and-pinion
• Price: $795
   

Askar 71f specifications

• Aperture: 71 mm
• Focal Length: 450 mm
• Focal Ratio: f/6.3
• Objective Lens: Triplet APO with two ED elements
• Coatings: Fully multi-coated
• Optical Tube Length: 420 mm
• Optical Tube Diameter: 90 mm
• Weight: 3.2 kg (7 lbs)
• Focuser: 2.5" dual-speed rack-and-pinion
• Price: $1,295
   

Svbony SV555 specifications

• Aperture: 80 mm
• Focal Length: 560 mm
• Focal Ratio: f/7
• Objective Lens: FPL-51 ED doublet
• Coatings: Fully multi-coated
• Optical Tube Length: 380 mm
• Optical Tube Diameter: 90 mm
• Weight: 2.5 kg (5.5 lbs)
• Focuser: 2" dual-speed rack-and-pinion
• Price: $499
   

Apertura 60EDR specifications

• Aperture: 60 mm
• Focal Length: 360 mm
• Focal Ratio: f/6
• Objective Lens: FPL-53 ED doublet
• Coatings: Fully multi-coated
• Optical Tube Length: 9.5 inches (241 mm) with dew shield retracted; 12.25 inches (311 mm) with dew shield extended
• Weight: 3.25 lbs (1.47 kg)
• Focuser: 2" dual-speed rack-and-pinion with 10:1 micro focusing
• Mounting: Hinged ring with 1/4-20 threaded foot for tripod or mount attachment
• Price: $419.95
   

Askar FMA 180 Pro specifications

• Aperture: 40 mm
• Focal Length: 180 mm
• Focal Ratio: f/4.5
• Objective Lens: Sextuplet air-spaced APO with two ED elements
• Coatings: Fully multi-coated
• Optical Tube Length: 167.5 mm
• Weight: 0.8 kg (1.76 lbs)
• Focuser: Internal helical focusing mechanism
• Back Focus: 55 mm from the base of the rear M48 male thread
• Image Circle: 44 mm, supporting full-frame sensors
• Mounting: Includes Vixen-style dovetail rail and finder mounting base
• Price: $419
   

Richard's pick

From my own experience, I’ve found that the William Optics RedCat 51 is an outstanding choice for wide-field astrophotography. Its Petzval design delivers sharp, pinpoint stars across the entire frame, making it a fantastic option for capturing sprawling nebulae and dense star fields. An Orion Complex photo I took with the RedCat 51 can be seen here - it's still one of my favorite all-time photos.

Another small refractor that has impressed me—though not as widely mentioned—is the Sharpstar 61mm EDPH III combined with the Sharpstar 0.75x reducer. Here is a Pleiades photo I took last year using very little acquisition time. This setup has proven that a compact, budget-friendly telescope can produce breathtaking wide-field astrophotography results. The 61mm aperture and excellent color correction make it a great alternative for those looking to get started without breaking the bank.

 

Buy a small APO refractor