William Optics

William Optics (WO) is a premium telescope brand based in Taiwan, well-known for its high-quality apochromatic refractors that combine beautiful craftsmanship with optical performance. These telescopes are especially popular among amateur astrophotographers and visual observers who want portability, ease of use, and outstanding image clarity.

What is an Apochromatic Refractor?

A refractor telescope uses lenses to gather and focus light. Basic (achromatic) refractors often suffer from chromatic aberration, where different wavelengths of light don’t all focus at the same point — causing purple or blue halos around stars or planets.

Apochromatic (APO) refractors correct this issue using multiple lenses (often a triplet), including special glass like FPL-53, to focus all colors of light more accurately. The result is:

• Sharper, high-contrast images

• No color fringing

• Ideal performance for astrophotography

Key Features of William Optics APO Telescopes

•  FPL-53 or FPL-51 Glass
  High-end ED (extra-low dispersion) glass for true apochromatic performance.

•  Air-Spaced Triplet or Doublet Designs
  Most imaging models use triplets; more affordable models (like ZenithStar) are doublets with excellent correction.

•  CNC-Machined Tubes
  Anodized aluminum tubes in vibrant colors (red, gold, blue) — durable and beautiful.

•  Built-in Bahtinov Mask
  The innovative cap doubles as a focusing mask, perfect for astrophotographers.

•  Rotatable Focusers
  Heavy-duty rack-and-pinion or FeatherTouch-compatible focusers allow precise focusing and easy framing.

•  Field Flatteners & Reducers
  WO offers a wide range of matched flatteners to eliminate edge distortion in images.

Popular Series

RedCat Series

• Small, ultra-portable, wide-field imaging scopes.

• Ideal for Milky Way, large nebulae, and travel.

ZenithStar (ZS) Series

• Compact and affordable doublets or triplets.

• Great balance between portability and performance.

Gran Turismo (GT) Series

• High-quality triplets with better mechanics and focusers.

• Designed for more serious imaging setups.

Fluorostar (FLT) Series

• Large-aperture triplets for deep-sky astrophotography.

• Observatory-level quality.

Who Should Use William Optics APO Refractors?

Astrophotographers: Especially those using DSLR or dedicated astronomy cameras.
Visual Observers: Excellent for planetary, lunar, and wide-field deep sky views.
Traveling Astronomers: Many models are lightweight and airline-carry-on friendly.
Beginners Seeking Quality: Easy to use and maintain compared to reflectors.

Here’s a comparison table of the most popular William Optics APO refractor telescopes, ranging from compact travel scopes to large-aperture astrographs. This includes the RedCat, ZenithStar, Gran Turismo (GT), and Fluorostar (FLT) series.

William Optics APO Refractor Comparison Table